This page shows what was measured, who it was measured in, and what that does not settle.
What Verapamil does in the body
In circuits that loop through that relay, blocking it stops the loop and the rhythm reverts.
The electrical relay between the top and bottom chambers of the heart runs on calcium rather than sodium, unlike most heart tissue. Verapamil sits inside the calcium channel and blocks it, so the relay slows and a racing pulse comes down. The same block relaxes artery muscle, which lowers blood pressure and eases angina, and it also weakens the squeeze of the heart itself — which is helpful in some conditions and dangerous in a heart that is already failing.
Why people take it. Chest pain, a racing or irregular heartbeat, and high blood pressure
What happened in people
Eighteen-month mortality after infarction 11.1% against 13.8%, not statistically significant at p=0.11
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
The recorded finding that sits closest to something a person would notice. Written into the record, not signed off, and it carries no population or interval.
Mortality 11.1% against 13.8%, p=0.11 (HR 0.80, 95% CI 0.61 to 1.05); major events 18.0% against 21.6%, p=0.03 (HR 0.80, 95% CI 0.64 to 0.99)
Repeated elsewhere
Partially Replicated
What this does not prove. A study that did not show an effect does not show that no effect exists anywhere.
The limits of this study, and where it came from
Main limit. The benefit was confined to the subgroup without heart failure in the coronary care unit: mortality HR 0.64 (0.44 to 0.94) without heart failure against 1.05 (0.72 to 1.54) with it.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Immediate-release tablet, sustained-release tablet and capsule, chronotherapeutic overnight-release formats, and an intravenous bolus
Interval reported. 95% CI 0
Written into the record, not signed off as a reviewed claim.
CLVer: verapamil and intensive diabetes management in newly diagnosed type 1 diabetes (NCT04233034) · a recorded source, not a stored snapshot
First occurrence of all-cause death, non-fatal myocardial infarction or non-fatal stroke
✓ The study showed what it set out to show
Who was studied
INVEST (JAMA 2003;290:2805-2816)
How many people
22576
Study design
Phase 4, randomised, open label, blinded endpoint
Compared against
Not recorded for this study
Kind of result
Living longer, or avoiding a major event
What was found
9.93% against 10.17%; relative risk 0.98 (95% CI 0.90 to 1.06) over a mean 2.7 years
Repeated elsewhere
Unreplicated
What this does not prove. Meeting one endpoint in one population does not carry to other goals or other people.
The limits of this study, and where it came from
Main limit. A comparison of strategies rather than of molecules: by 24 months, 81.5% of the calcium antagonist arm was still on verapamil and 77.5% of the comparator arm still on atenolol, with trandolapril and hydrochlorothiazide layered onto both. Open-label design with blinded endpoint adjudication.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Immediate-release tablet, sustained-release tablet and capsule, chronotherapeutic overnight-release formats, and an intravenous bolus
Interval reported. 95% CI 0
Written into the record, not signed off as a reviewed claim.
Adjusted between-group difference 0.14 pmol/mL (95% CI 0.01 to 0.27), p=0.04, equating to a 30% higher C-peptide level at 52 weeks
Repeated elsewhere
Partially Replicated
What this does not prove. Meeting one endpoint in one population does not carry to other goals or other people.
The limits of this study, and where it came from
Main limit. HbA1c did not differ: 6.6% against 6.9%, adjusted difference -0.3% (95% CI -1.0 to 0.4). The endpoint is a mechanistic surrogate in 88 children, and durability beyond 52 weeks is unknown.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Immediate-release tablet, sustained-release tablet and capsule, chronotherapeutic overnight-release formats, and an intravenous bolus
Interval reported. 95% CI 0
Written into the record, not signed off as a reviewed claim.
CLVer: verapamil and intensive diabetes management in newly diagnosed type 1 diabetes (NCT04233034) · a recorded source, not a stored snapshot
What we know
RNAWiki holds 3 written-up human studies for this substance, each with the question it asked.
How we know it
Each card names the study, the number of people and what the study set out to measure.
What this does not prove
These summaries were written by a person and have not been signed off as reviewed claims.
Why it matters
A study that failed is as informative as one that worked, and both are here.
What we still do not know
No reviewed claim exists, so no exact population, effect size or interval is published yet.
What it changes in the body◇Read from sources, not yet reviewed
The path through the body
From what a person takes to what changes. A solid line is a step measured in people. A dashed line is a step nobody has measured that way.
Where a source records it acting
Heart: Dilates the main coronary arteries and coronary arterioles and inhibits coronary artery spasm, increasing myocardial oxygen delivery
US prescribing information · 006cf920-04ae-0b53-cb91-85481972abc2 · read 2026-08-27
Blood and vessels: Exerts antihypertensive effects by decreasing systemic vascular resistance
US prescribing information · 006cf920-04ae-0b53-cb91-85481972abc2 · read 2026-08-27
Start
Verapamil
What a person takes: Immediate-release tablet, sustained-release tablet and capsule, chronotherapeutic overnight-release formats, and an intravenous bolus.
The measurement behind this step
The intravenous route exists for immediate termination of supraventricular tachycardia and acute rate control, and delivers a different enantiomer ratio than the oral route because the more cardioactive S-enantiomer is preferentially removed on first pass. The chronotherapeutic formulations were designed to release drug in the early morning, when cardiovascular events cluster; the outcome hypothesis behind that design was not confirmed.
Reaching the cell
It reaches the channel from the inside
Unlike the calcium blockers used for blood pressure, verapamil has to get into the cell first and then blocks the channel from within, and only while the channel is open.
╌╌Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.
The measurement behind this step
Verapamil binds the phenylalkylamine site within the pore of Cav1.2, accessible from the cytoplasmic face and only in the open state. Block is therefore strongly use-dependent: the faster the tissue is depolarising, the more of it is blocked.
Two small regions of the heart run on calcium rather than sodium. Blocking calcium slows both, so the pulse falls and a rhythm that loops through the relay is interrupted.
──Measured in people. Written by a person from the study named beside the step. Not signed off as a reviewed claim.
The measurement behind this step
Sinoatrial automaticity and atrioventricular nodal conduction depend on L-type calcium current. Verapamil prolongs AV nodal refractoriness and terminates reentrant supraventricular tachycardias whose circuit includes the node. In digitalised atrial fibrillation trials, resting ventricular rates below 50 occurred in 15% of patients.
The same channel in artery muscle is blocked too, so vessels widen. That lowers blood pressure and eases angina by cutting the work the heart has to do.
──Measured in people. Written by a person from the study named beside the step. Not signed off as a reviewed claim.
The measurement behind this step
Reduced calcium influx into vascular smooth muscle lowers systemic vascular resistance, which partially offsets the negative inotropic effect. The label states that in most patients the negative inotropy is compensated by afterload reduction without net impairment of ventricular performance.
Blocking calcium in heart muscle means each beat is less forceful. In a healthy heart that does not matter. In a failing one it can be the difference between compensated and not.
──Measured in people. Written by a person from the study named beside the step. Not signed off as a reviewed claim.
The measurement behind this step
Congestive heart failure or pulmonary oedema developed in 87 of 4,954 trial patients, 1.8%. The label contraindicates severe left ventricular dysfunction, directs avoidance below 30% ejection fraction, and directs avoidance at any degree of ventricular dysfunction if a beta-blocker is co-prescribed.
Bowel muscle contracts using the same calcium channel as artery muscle. Blocking it slows the bowel, which is why constipation is the most common complaint by a wide margin.
──Measured in people. Written by a person from the study named beside the step. Not signed off as a reviewed claim.
The measurement behind this step
Constipation occurred in 7.3% of 4,954 patients, more than twice the rate of the next most common adverse effect. Reversible non-obstructive paralytic ileus has been reported infrequently. The effect is dose-related and is the leading reason for discontinuation.
Two large trials looked for a survival benefit. After a heart attack, deaths fell but not convincingly. Against a beta-blocker strategy in coronary disease, the two were identical.
──Measured in people. Written by a person from the study named beside the step. Not signed off as a reviewed claim.
The measurement behind this step
DAVIT-II: 18-month mortality 11.1% against 13.8%, p=0.11; major events 18.0% against 21.6%, p=0.03. INVEST: primary outcome 9.93% against 10.17%, relative risk 0.98 (95% CI 0.90 to 1.06), in 22,576 patients over a mean 2.7 years.
No suggested links are held for this record, so nothing is hidden from this path.
What we know
The record describes 6 steps from taking it to an effect in a person.
How we know it
Each step names the study behind it in the technical detail beside it.
What this does not prove
A change inside the body is a reason to look. It is not a result in a person.
Why it matters
A reader can see exactly where the chain stops being measured in people.
What we still do not know
No reviewed claim binds any of these steps to a named population.
What is missing or unclear◇Read from sources, not yet reviewed
Were people like you studied?
RNAWiki cannot tell whether a study fits you. It can show who was in it, and where the result stops carrying.
Who was studied
People similar to this profile were included.
Adults with angina including the vasospastic form, adults needing ventricular rate control in atrial fibrillation or flutter, adults with recurrent supraventricular tachycardia, and adults with high blood pressure. Not people with severe left ventricular dysfunction, and not people with pre-excited atrial fibrillation.
Who is missing from the studies
Which groups were under-represented in the studies has not been recorded for this substance. Pregnancy, breastfeeding, children, older adults, and people with liver or kidney conditions are commonly excluded from trials; nothing here says whether they were.
What the label states about particular groups
On pediatric, the label states: “Safety and effectiveness in pediatric patients have not been established.”
US prescribing information · 5f665d08-e1e4-422a-88c2-d8834abf9e1a · read 2026-08-30
On older people, the label states: “Clinical studies of Verapamil Hydrochloride Extended-release Capsules (PM) were not adequate to determine if subjects aged 65 or over respond differently from younger patients.”
US prescribing information · 5f665d08-e1e4-422a-88c2-d8834abf9e1a · read 2026-08-30
On people who are pregnant, the label states: “Reproduction studies have been performed in rabbits and rats at oral doses up to 1.9 (15 mg/kg/day) and 7.5 (60 mg/kg/day) times the human oral daily dose, respectively, and have revealed no evidence of teratogenicity.”
US prescribing information · 5f665d08-e1e4-422a-88c2-d8834abf9e1a · read 2026-08-30
On people who are breastfeeding, the label states: “In case studies where verapamil concentration in human milk was calculated, the nursing infant doses ranged from less than 0.01% to 0.1% of the mother's verapamil dose.”
US prescribing information · 5f665d08-e1e4-422a-88c2-d8834abf9e1a · read 2026-08-30
Where the result stopped carrying
DAVIT-II missed all-cause mortality at p=0.11 and reported the composite as its positive result
The post-infarction benefit disappeared entirely in patients who had heart failure at admission (HR 1.05)
INVEST found no advantage over a beta-blocker strategy in 22,576 patients with coronary disease
Constipation, at 7.3%, is the dominant reason the drug is stopped and is not a cardiac effect at all
This is a scope explorer, not a diagnosis engine.
It shows who was studied so you can see whether people similar to you were included.
RNAWiki cannot tell whether a study fits you. It can show who was in it.
What it would be like to take◇Read from sources, not yet reviewed
Why it might seem to do nothing
A real effect and a noticed effect are different things. These are the recorded reasons the two come apart.
It was studied in different people
The people in the studies were not much like the reader.
On this record: Which groups were under-represented in the studies has not been recorded for this substance. Pregnancy, breastfeeding, children, older adults, and people with liver or kidney conditions are commonly excluded from trials; nothing here says whether they were.
The evidence may simply be wrong
Small early studies often do not hold up.
On this record: RNAWiki has not yet published a reviewed conclusion for this use.
Other reasons RNAWiki checked and found nothing for (11)
It was studied for a different goal
The studies measured something else entirely. Nothing in this record points to this reason.
A different form was studied
The studied form is not the form on the shelf. Nothing in this record points to this reason.
There was nothing to correct
Where a level is already normal, topping it up may change nothing. Nothing in this record points to this reason.
Something else had to happen too
In the studies it was paired with training, a diet or another treatment. Nothing in this record points to this reason.
The change is too small to feel
A real change can still sit below what a person notices. Nothing in this record points to this reason.
Day-to-day swing hides it
Sleep, food, stress and time of day move most numbers more than this would. Nothing in this record points to this reason.
Not enough time yet
The studies ran longer than the person has waited. Nothing in this record points to this reason.
It was not taken as studied
Missed days change the result, and studies count them. Nothing in this record points to this reason.
Something else changed at the same time
Two changes at once cannot be told apart afterwards. Nothing in this record points to this reason.
The product may not be what it says
Contents of a sold product are not always what the label states. Nothing in this record points to this reason.
No recorded reason
RNAWiki has nothing stored that would explain it. Nothing in this record points to this reason.
None of these is a reason to take more. Taking more is not a step this page ever suggests.
What it would be like to take◇Read from sources, not yet reviewed
What taking it involves
The recorded facts about getting hold of it and using it. Nothing here is a suggestion about what you should do.
How it is supplied
Given by a clinician
❝ Quoted from a source
Where this came from
Copied from a source RNAWiki stored, with the source named.
Read from the recorded approval status.
No source is stored against this line.
Form and route
Immediate-release tablet, sustained-release tablet and capsule, chronotherapeutic overnight-release formats, and an intravenous bolus
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
The form and route recorded on this substance.
No source is stored against this line.
Who oversees it
RNAWiki has not recorded a supervision or regulatory status for this substance.
❝ Quoted from a source
Where this came from
Copied from a source RNAWiki stored, with the source named.
No register row and no identity class settled the question.
No source is stored against this line.
What is in the pack
The intravenous route exists for immediate termination of supraventricular tachycardia and acute rate control, and delivers a different enantiomer ratio than the oral route because the more cardioactive S-enantiomer is preferentially removed on first pass.
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
Recorded notes on how this is sold. The rest of the recorded wording: The chronotherapeutic formulations were designed to release drug in the early morning, when cardiovascular events cluster; the outcome hypothesis behind that design was not confirmed.
No source is stored against this line.
Where it is registered
Regulatory records are listed in the technical disclosure at the foot of this page.
# Counted from records
Where this came from
A count of rows RNAWiki holds. It describes our records, not your body.
Register entries are stored per jurisdiction and shown with their dates.
No source is stored against this line.
Why people stop
Not recorded.
∅ Nothing recorded
Where this came from
RNAWiki holds nothing here and says so rather than guessing.
No record of why people stopped taking it is stored for this substance.
No source is stored against this line.
What it would be like to take◇Read from sources, not yet reviewed
What can go wrong
Sorted by where each line came from. A regulator's label and a report somebody sent in are not the same kind of fact.
·Worth asking a clinician aboutWritten into the record from the studies named on this page
Contraindicated in severe left ventricular dysfunction, systolic pressure below 90 mmHg or cardiogenic shock, sick sinus syndrome or high-grade AV block without a pacemaker, and atrial flutter or fibrillation with an accessory bypass tract. Avoid below 30% ejection fraction and in any ventricular dysfunction when a beta-blocker is co-prescribed. Constipation affects 7.3% and paralytic ileus has been reported. Transaminase elevations occur, occasionally with hepatocellular injury. It raises digoxin levels and inhibits CYP3A4.
Nobody counted how many people took this and were fine, so this cannot be turned into a rate.
Over a long time. No completed tested study window is recorded, so long-term effects are not established by the registry record.
Groups the studies covered thinly. Which groups were under-represented in the studies has not been recorded for this substance. Pregnancy, breastfeeding, children, older adults, and people with liver or kidney conditions are commonly excluded from trials; nothing here says whether they were.
What is missing or unclear◇Read from sources, not yet reviewed
Does the exact form matter?
Evidence belongs to the exact thing that was tested. A different salt, a different mixture or a different preparation is a different question.
The form that was studied
Immediate-release tablet, sustained-release tablet and capsule, chronotherapeutic overnight-release formats, and an intravenous bolus
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
The form used in the studies cited on this page.
No source is stored against this line.
What is sold
The chronotherapeutic formulations were designed to release drug in the early morning, when cardiovascular events cluster; the outcome hypothesis behind that design was not confirmed.
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
Recorded notes on which forms are sold and how they compare.
No source is stored against this line.
What is recorded as being sold
166 products list this as an active ingredient in the United States drug directory. 162 of them contain it and nothing else.
FDA National Drug Code directory · 71872-7291 · read 2026-08-29
They are sold as capsule, capsule, delayed release, capsule, delayed release pellets, capsule, extended release, injection and injection, solution, taken intravenous and oral.
FDA National Drug Code directory · 71872-7291 · read 2026-08-29
The regulator's established pharmacologic class for it is calcium channel antagonists [moa], calcium channel blocker [epc] and cytochrome p450 3a inhibitors [moa].
FDA National Drug Code directory · 71872-7291 · read 2026-08-29
99 published labels name it as an active ingredient. 98 of them describe this substance alone, which is where its own label text on this page comes from.
US prescribing information · df77b8d1-1d2b-4fea-a1e9-153bd25008a6 · read 2026-08-29
Those labels are classed as human prescription drug.
US prescribing information · df77b8d1-1d2b-4fea-a1e9-153bd25008a6 · read 2026-08-29
Recorded price in US: 0.07108–0.11742 USD per one unit as the pricing file counts it — a tablet, capsule, patch or single item, across 13 priced products whose strengths and pack forms differ, as of 2026-08-26, paid by retail pharmacies buying the product, as surveyed by the Centers for Medicare & Medicaid Services. It is not a list price, an insurance price, or what anyone pays at a counter..
Recorded source · 2026-08-26 · read 2026-08-28
Evidence carries across two names for one substance. It does not carry across a salt, a mirror form or a mixture.
What it would be like to take◇Read from sources, not yet reviewed
What you could measure
This one is decided with a clinician, so this section holds questions to ask rather than a plan to run.
RNAWiki could not confidently classify this substance, so no self-experiment plan is offered.
Questions worth asking
Which of the trials of Verapamil studied people like me?
What was measured, and for how long?
Was the result a laboratory value or a health outcome?
What would we watch for, and when would we stop?
Tracking can show whether something changed for you. It cannot show what caused it.
RNAWiki records evidence. It does not say whether this substance is right for you.
What is missing or unclear◇Read from sources, not yet reviewed
Claims that go past the evidence
Things said about this substance that sound reasonable, and the exact step that is missing between the evidence and the claim.
✗Goes past the evidence
That verapamil reduces mortality after myocardial infarction — the trial that looked missed its mortality endpoint
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
✗Goes past the evidence
That INVEST showed the verapamil strategy superior, when the published conclusion is that it was as clinically effective as the comparator
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
✗Goes past the evidence
That preserved C-peptide in newly diagnosed type 1 diabetes will produce better long-term control, when HbA1c did not differ at 52 weeks
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
✗Goes past the evidence
That the rate-control effect is interchangeable with diltiazem — verapamil depresses contractility substantially more at equivalent nodal effect
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
What is missing or unclear◇Read from sources, not yet reviewed
What nobody knows yet
Open questions, each with why it is open and what would close it.
Missing populations
Which groups were under-represented in the studies has not been recorded.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Missing long-term data
No completed tested study window is recorded.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
No reviewed conclusion
RNAWiki has not yet published a reviewed conclusion for this use.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Missing interaction studies
No interaction was found in the registers checked. Not finding one is not the same as showing there is none.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Formulation uncertainty
Several salts, forms or products of Verapamil are recorded. Results from one form may not transfer to another.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Mechanism not reviewed
No reviewed mechanism story exists for this substance.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
What happened in people◇Read from sources, not yet reviewed
Check any of this yourself
Every line above traced back to the study it came from. This is the technical layer, and the vocabulary changes here.
Every line above can be traced to the study named beside it. Follow the link and read it.
DAVIT-II: mortality missed at p=0.11, events met at p=0.03
In plain words
Nearly eighteen hundred patients were given verapamil or a dummy tablet from the second week after a heart attack. Deaths fell from 13.8% to 11.1%, which was not statistically convincing. The combined count of deaths and repeat heart attacks did reach significance.
What was measured
Eighteen-month mortality and major event rate after myocardial infarction, with a prespecified split by heart failure at admission
Effect estimate
No reviewed effect estimate exists for this record.
Limits
This entry records a failure.
From the source
The Danish Verapamil Infarction Trial II randomised 878 patients to verapamil 360 mg daily and 897 to placebo, starting in the second week after admission and continuing up to 18 months, mean 16. There were 95 deaths and 146 major events on verapamil against 119 deaths and 180 major events on placebo. Eighteen-month mortality was 11.1% against 13.8% (p=0.11, hazard ratio 0.80, 95% CI 0.61 to 1.05) — not significant. Major event rate, defined as death or reinfarction, was 18.0% against 21.6% (p=0.03, hazard ratio 0.80, 95% CI 0.64 to 0.99). The benefit was confined to patients without heart failure in the coronary care unit: mortality 7.7% against 11.8% (p=0.02, HR 0.64, 95% CI 0.44 to 0.94) without heart failure, and 17.9% against 17.5% (p=0.79, HR 1.05, 95% CI 0.72 to 1.54) with it. The same split found in the diltiazem trial appeared here in a different drug and a different country.
Written into the record, not signed off as a reviewed claim
INVEST: identical to an atenolol strategy in 22,576 patients
In plain words
The largest verapamil trial compared a verapamil-based plan against a beta-blocker-based plan in twenty-two thousand people with both high blood pressure and coronary disease. The rates of death, heart attack and stroke came out the same.
What was measured
First occurrence of all-cause death, non-fatal myocardial infarction or non-fatal stroke
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
INVEST randomised 22,576 hypertensive patients aged 50 or over with coronary artery disease, at 862 sites in 14 countries, to a calcium antagonist strategy based on sustained-release verapamil or a non-calcium-antagonist strategy based on atenolol, each with trandolapril and hydrochlorothiazide added to reach blood pressure goals. After 61,835 patient-years, mean 2.7 per patient, 2,269 patients had a primary outcome of death from any cause, non-fatal myocardial infarction or non-fatal stroke: 9.93% on the verapamil strategy and 10.17% on the atenolol strategy, relative risk 0.98 (95% CI 0.90 to 1.06). Two-year blood pressure control was similar, with 71.7% and 70.7% reaching below 140/90 mmHg. The conclusion is that the verapamil-trandolapril strategy was as clinically effective as the atenolol-hydrochlorothiazide strategy. As clinically effective is not more effective, and this trial was designed and reported as a comparison of strategies rather than of molecules — by 24 months only 81.5% of the verapamil arm was still on verapamil.
Written into the record, not signed off as a reviewed claim
Constipation in 7.3%, heart failure in 1.8%, from a database of 4,954 patients
In plain words
The commonest problem with verapamil is not cardiac. Seven in a hundred become constipated, because the gut muscle uses the same calcium channel as artery muscle. Nearly two in a hundred developed heart failure or fluid on the lungs.
What was measured
Adverse reaction rates from a pooled clinical trial population of 4,954 patients
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
From the clinical trial database of 4,954 patients: constipation 7.3%, dizziness 3.3%, nausea 2.7%, hypotension 2.5%, headache 2.2%, oedema 1.9%, congestive heart failure or pulmonary oedema 1.8% (87 patients), fatigue 1.7%, dyspnoea 1.4%, bradycardia below 50 beats per minute 1.4%, total AV block of any degree 1.2% with second- and third-degree at 0.8%, rash 1.2%, flushing 0.6%. Reversible non-obstructive paralytic ileus has been reported infrequently. In the subset treated for rate control in digitalised atrial fibrillation or flutter, ventricular rates below 50 at rest occurred in 15% and asymptomatic hypotension in 5%. The label also records elevations of transaminases, sometimes transient and sometimes persisting, with several cases of hepatocellular injury.
Source
Verapamil hydrochloride United States prescribing information, Warnings and Adverse Reactions sections
Role in the trial
Not matched to a registered study
Identity check
no open identity hold
Audit mark
verified
Review state
Written into the record, not signed off as a reviewed claim
Two contraindications that describe the drug own mechanism turning on the patient
In plain words
Verapamil weakens the heart squeeze, so it must not be used in a heart that is already failing badly. And it blocks the normal electrical relay, so in people with an extra pathway it can push the impulse down that pathway instead and make the rhythm faster, not slower.
What was measured
Not recorded
Effect estimate
No reviewed effect estimate exists for this record.
Limits
This entry records a failure.
From the source
Contraindications are severe left ventricular dysfunction; hypotension below 90 mmHg systolic or cardiogenic shock; sick sinus syndrome or second- or third-degree AV block without a functioning pacemaker; atrial flutter or fibrillation with an accessory bypass tract such as Wolff-Parkinson-White or Lown-Ganong-Levine; and hypersensitivity. The Warnings section directs avoiding the drug at ejection fraction below 30% or with moderate to severe cardiac failure symptoms, and in any degree of ventricular dysfunction if a beta-adrenergic blocker is also being given, because the negative inotropic effects are additive. Both contraindications are the therapeutic mechanism applied to the wrong heart: negative inotropy where contractile reserve is already exhausted, and AV nodal block where an alternative conduction route exists.
Source
Verapamil hydrochloride United States prescribing information, Contraindications and Warnings sections
Role in the trial
Not matched to a registered study
Identity check
no open identity hold
Audit mark
caution
Review state
Written into the record, not signed off as a reviewed claim
A beta-cell result in type 1 diabetes, on a surrogate, in 88 children
In plain words
Verapamil is being investigated for something with no connection to the heart: preserving the insulin-producing cells in newly diagnosed type 1 diabetes. A randomised trial in eighty-eight children found more insulin production after a year. Blood sugar control was not measurably better.
What was measured
That preserved C-peptide secretion at one year will translate into better long-term glycaemic control or fewer complications — the trial measured the surrogate, found no HbA1c difference, and says longitudinal durability is unknown
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
The CLVer trial randomised 88 children and adolescents aged 7 to 17 within a month of type 1 diabetes diagnosis to once-daily oral verapamil (n=47) or placebo (n=41), within a factorial design also testing intensive diabetes management. The primary endpoint was area under the curve for C-peptide stimulated by a mixed-meal tolerance test at 52 weeks. Mean C-peptide AUC went from 0.66 to 0.65 pmol/mL on verapamil and from 0.60 to 0.44 on placebo, an adjusted between-group difference of 0.14 pmol/mL (95% CI 0.01 to 0.27, p=0.04), equating to a 30% higher C-peptide level at 52 weeks. HbA1c at 52 weeks was 6.6% against 6.9%, adjusted difference -0.3% (95% CI -1.0 to 0.4) — not significant. Treatment-related non-serious adverse events occurred in 17% against 20%. The rationale is that calcium blockade reduces thioredoxin-interacting protein overexpression, which drives beta-cell apoptosis in preclinical models. This is a genuine randomised result on a mechanistic surrogate, in 88 children, with a confidence interval whose lower bound is 0.01, and with no measurable difference in the outcome patients experience.
Written into the record, not signed off as a reviewed claim
Two calcium blockers, two countries, the same subgroup
In plain words
The Danish verapamil trial and the American diltiazem trial were run separately with different drugs. Both found the same thing: benefit in patients whose hearts were coping, harm or nothing in patients whose hearts were failing.
What was measured
That either trial subgroup result stands alone — each is a subgroup analysis, and what makes them credible is that they replicate each other across drugs, countries and endpoints
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
DAVIT-II found post-infarction mortality of 7.7% against 11.8% (HR 0.64, 95% CI 0.44 to 0.94) in patients without heart failure in the coronary care unit, and 17.9% against 17.5% (HR 1.05, 95% CI 0.72 to 1.54) in those with it. MDPIT, published two years earlier with diltiazem in 2,466 patients, found cardiac event hazard ratios of 0.77 (0.61 to 0.98) without radiographic pulmonary congestion and 1.41 (1.01 to 1.96) with it, interaction p=0.0042. Two independently designed trials of two different molecules binding two different sites on the same channel converged on the same modifier. That convergence is the strongest evidence either trial provides, and it is a class-level physiological finding — negative inotropy is tolerable when there is contractile reserve and not when there is none — rather than a property of either drug.
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What is not here
7 questions this page could not answer
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What was measured, goal by goal — found nothing in the sources checked.
How close this is to real life — found nothing in the sources checked.
Felt, measured, or meaningful — found nothing in the sources checked.
How long anything takes — found nothing in the sources checked.
What it may clash with — found nothing in the sources checked.
Other ways to the same goal — found nothing in the sources checked.
What changed on this page — found nothing in the sources checked.
The record as stored
The full record, for auditing
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The older medicine-wide conclusion held in this record
Written for a clinical reader, and about the medicine as a whole rather than about one indication, population and set of trials. RNAWiki does not treat it as a programme conclusion and no reviewer has signed it off in that form. It is here word for word because it is what the record holds.
A phenylalkylamine calcium blocker that slows the AV node harder than any other oral drug in its class, whose post-infarction trial in 1,775 patients missed mortality at p=0.11 while cutting major events by 20% (p=0.03), and which in 22,576 hypertensive patients with coronary disease matched an atenolol strategy exactly (RR 0.98) rather than beating it.
Recorded evidence blocks (11)
Q1
On the Verapamil label: indicated for what?
"Verapamil hydrochloride extended-release tablets are indicated for the treatment of hypertension, to lower blood pressure. Lowering blood pressure reduces the risk of fatal and nonfatal cardiovascular events, primarily strokes and myocardial infarctions.": indications and usage on Verapamil's label. DailyMed label · ce9ab27a-e03b-4e40-a0e0-b586cd75dead · 2026-06-29
Q2
82 registered trials of Verapamil — at which phases?
Registered studies posting no result
64 of 82
82 registered studies of Verapamil: 29 phase1, 18 phase4, 15 phase2, 9 na, 9 phase3, 4 early phase1, 4 na or unstated. CLINICALTRIALS_SNAPSHOT · 2026-09-01
2.8 to 7.4 hours; The mean elimination half-life in single-dose studies ranged from 2.8 to 7.4 hours.
tmaxpharmacokinetics
2 hours; Peak plasma concentrations are reached between 1 and 2 hours after oral administration.
bioavailabilitypharmacokinetics
20 %; Because of rapid biotransformation of verapamil during its first pass through the portal circulation, bioavailability ranges from 20% to 35%.
metabolismpharmacokinetics
and metabolism: With the immediate-release formulation, more than 90% of the orally administered dose of verapamil hydrochloride is absorbed.
recorded 2026-06-29 · last checked 2026-09-04
Q6
Which running trial of Verapamil could settle vo2max?
NCT05569382 measures Maximal oxygen consumption (VO2 max), reading out 2027-12-31.
1 open trial; n 100; "Treatment Effects of Bisoprolol and Verapamil in Symptomatic Patients With Non-obstructive Hypertrophic Cardiomyopathy"
Show the evidence
TrialNCT05569382
"Treatment Effects of Bisoprolol and Verapamil in Symptomatic Patients With Non-obstructive Hypertrophic Cardiomyopathy"; n 100; "Maximal oxygen consumption (VO2 max)"; 2027-12-31
Q7
Which 34 trials of Verapamil posted no result?
Posted no result
34 of 34 completed trials
Registrations
NCT00518947, NCT00000556, NCT01467687, NCT00668967, NCT00707551 and NCT01295047, and 28 more
Completion dates
oldest 1999-06; newest 2024-05-20
Show the evidence
Trial
NCT00518947
1999-06
NCT00000556
2002-09
NCT01467687
2007-08
NCT00668967
2008-07
NCT00707551
2008-11
NCT01295047
2008-12
14 further recorded trials
NCT00712894
2009-08
NCT00804895
2009-10
NCT01943487
2009-12
NCT00593463
2010-05
NCT00313157
2010-09
NCT01197781
2010-10
NCT01655316
2011-08
NCT01471704
2011-11
NCT01655303
2011-12
NCT02111317
2013-11
NCT01669304
2014-10
NCT01675362
2014-10
NCT03033537
2016-01-20
NCT02235558
2016-03-21
Q8
At the median, Verapamil's trials enrolled 59 people — anything larger?
Median enrolment
59
Largest enrolment
22213
Registered trials counted
80
Q9
What do 1256 spontaneous reports say about Verapamil — and not say?
These are reports people sent to a regulator. They do not show the medicine caused the reaction. Nobody counted how many people took the medicine and reported nothing. The same event can be reported more than once, and many reports are incomplete. News coverage, lawsuits and new warnings change how often people report. A count is not a rate and not a risk.
Verapamil appears in spontaneous reports to regulators. Across the 10 most-reported reaction terms, 1256 reaction mentions were counted: drug hypersensitivity 247; hypotension 247; bradycardia 170; drug interaction 137. FAERS via Open Targets · CHEMBL1280 · 2026-06-24
Show the evidence
drug hypersensitivity
247
hypotension
247
bradycardia
170
drug interaction
137
toxicity to various agents
100
suicide attempt
87
4 more recorded rows
cardiogenic shock
82
atrioventricular block complete
81
hyperkalaemia
57
atrial fibrillation
48
recorded 2026-06-24 · last checked 2026-09-04
Q10
Which 10 reactions does Verapamil's label not list?
Cytochrome inducers/inhibitors: In vitro metabolic studies indicate that verapamil is metabolized by cytochrome P450 CYP3A4, CYPIA2, CYP2C8, CYP2C9, and CYP2CI8.
drug_interactions
Clinically significant interactions have been reported with inhibitors of CYP3A4 (e.g., erythromycin, ritonavir) causing elevation of plasma levels of verapamil while inducers of CYP3A4 ( e.g., rifampin) have caused a lowering of plasma levels of verapamil.
drug_interactions
HMG-CoA reductase inhibitors: The use of HMG-CoA reductase inhibitors that are CYP3A4 substrates in combination with verapamil has been associated with reports of myopathy/rhabdomyolysis.
drug_interactions
Lower starting and maintenance doses of other CYP3A4 substrates (e.g., atorvastatin) may be required as verapamil may increase the plasma concentration of these drugs.
ChEMBL 37 — CC BY-SA 3.0 Unported · ClinicalTrials.gov — US Government work · Open Targets 26.06 — CC0 · mixed register set; per-register licences in docs/specs/corpus-20k-sources.md · openFDA / DailyMed — US Government work
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✓ public claims reviewed: 0 reviewed claim(s); drafts are never rendered
✓ source coverage passed: 7 source rows
✓ no critical contamination: no quarantine open
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