What is amlodipine?
Amlodipine is a calcium channel blocker of the dihydropyridine type. It blocks calcium entry into the smooth muscle of the arterial wall. Without calcium the muscle cannot contract, the vessels widen, peripheral resistance falls and blood pressure with it.
The point that makes it interesting in a training context: amlodipine acts almost exclusively on the vessels and barely on the heart itself. It does not lower heart rate. A beta blocker caps your maximum heart rate and with it, measurably, your endurance performance. A calcium channel blocker does not.
This information is for research and educational purposes only. No medical advice.
Comparison
Blood pressure drugs compared
Blood pressure drugs from the TPD lexicon, as described there. Tap a card to open its entry.
Simplified: each class acts at a different point. Amlodipine widens the arteries and does not lower heart rate, beta blockers slow the heart. 71
How it works
The half-life of 30 to 50 hours is unusually long for a blood pressure agent and explains three things at once. First, one dose per day is enough. Second, it takes seven to ten days for the full effect to appear, because the level has to build. Third, it keeps working for days after stopping.
In practice: anyone measuring after three days and finding the target range unmet measured too early. Increasing at that point regularly drives pressure unnecessarily low once the build-up finishes. Conversely, a missed dose does not need catching up, the buffer is too large for that.
Where it acts
Where amlodipine acted in studies
Tap a point or a card. Colour = L-type calcium channel, grey = observed in studies.
- Arteries
Less calcium entry into the vessel muscle, the arteries widen and blood pressure falls7
CaV1.2 - Heart
More heart failure than with chlorthalidone, yet not harmful in severe heart failure1
Observed in trials - Brain
Fewer strokes than with the atenolol regimen2
Observed in trials - Glucose metabolism
New diabetes less often than with the atenolol regimen2
Observed in trials - Liver
About 90 percent is broken down in the liver, 40 to 60 percent higher levels in liver impairment5
Observed in trials
Targets in the ChEMBL database7
Compound CHEMBL1491 (Amlodipin): one recorded mechanism, Blocker, direct binding.
- Gene
- CACNA1C
- UniProt
- Q13936, Q13698, Q01668, O60840
- ChEMBL
- CHEMBL2095229
- Action
- Blocker, direct binding
Use and dosing
Dosing
Dosing, titration and syringe
Loading the dosing information …
- Getting started and stepping up, drawn as a staircase
- Units on the U-100 syringe for every step
- How long one vial lasts
What the research shows
The evidence is unusually dense for a blood pressure agent, but not uniformly flattering. ALLHAT (JAMA 2002) compared over 33,000 high-risk patients and found no difference in the primary endpoint between amlodipine and the diuretic chlorthalidone. But heart failure occurred 38 percent more often under amlodipine. That is the single most important caveat about the substance and belongs, honestly, on every page about it.
ASCOT-BPLA (Lancet 2005) came out clearly in amlodipine's favour: an amlodipine-based regimen beat an atenolol-based one on strokes and all-cause mortality. VALUE (Lancet 2004) showed faster pressure reduction in the first months and fewer heart attacks under amlodipine than under valsartan.
PRAISE (NEJM 1996) is the reason amlodipine may be used at all in existing heart failure: it proved safe, while older calcium channel blockers caused harm in that setting.
Study results
What the trials measured
Interactive: switch tabs, tap points, show or hide arms. Arms are named relative to each other, no dosing advice.
Amlodipine versus chlorthalidone in high-risk hypertension1
Share with an event after 6 years, in percent
Values from the abstract, mean follow-up 4.9 years. No difference in the primary endpoint or all-cause mortality, heart failure more common with amlodipine (relative risk 1.38).
Amlodipine regimen versus atenolol regimen2
Share with an event over the whole trial, in percent (calculated)
Percentages calculated from the events in the abstract and the group size (9,639 versus 9,618). Perindopril could be added to amlodipine, bendroflumethiazide to atenolol. The trial was stopped early.
Amlodipine regimen versus valsartan regimen3
Cardiac events and cardiac death, in percent
No difference in the primary endpoint. Blood pressure with amlodipine was 4.0/2.1 mmHg lower after one month and still 1.5/1.3 mmHg lower after one year.
Severe chronic heart failure, 6 to 33 months4
Share with an event, in percent
1,153 patients with an ejection fraction below 30 percent. Neither difference was significant: amlodipine did not make things worse, unlike older calcium channel blockers.
Research status
Where the research stands
Amlodipine has been approved since 1992. On ClinicalTrials.gov 728 trials list amlodipine among their interventions, often as a comparator or in combination. Shown are the two large outcome trials from this entry that are listed there. ASCOT and PRAISE ran outside the registry. As of 26 Oct 2026. 8
- Preclinical Development as a long-acting calcium channel blocker
- Phase 1 no registered trial
- Phase 2 no registered trial
- Phase 3 2 trials, 2 completed
- Approval in the USA since 1992
Show all 2 phase 3 trials on a timelineHide timeline
ALLHAT · NCT00000542 · 33,357 participants, started Aug 1993, primary endpoint reached Mar 2002. Tests several agents.
Registry entry ↗ · Results: ALLHAT Officers and Coordinators, JAMA, 2002
VALUE · NCT06395194 · 15,313 participants, started Sept 1997, primary endpoint reached Sept 2003. Tests several agents.
Registry entry ↗ · Results: Julius et al., The Lancet, 2004
Bar: start to primary endpoint (planned for running trials). Green = completed, blue = progress until 26 Oct 2026.
Side effects
- Swollen ankles: by far the most common report, mostly in the evening and mostly at 10mg. Important to understand: this is not fluid retention in the sense of an excess, it is a local shift of fluid into tissue, because the small arteries widen more than the veins do. Diuretics do not help against it. Anyone affected usually does better on a lower dose plus a second agent than on 10mg alone.
- Headache and flushing: typical in the first days, usually settles on its own.
- Dizziness on standing: a sign that pressure sits too low.
- Gum overgrowth: rare, but documented and relevant with long-term use.
Tolerability
Side effects by dose
From the US label: these side effects rose with the dose. The study arms are named relative to each other.
| Event | Placebo | Lowest study dose | Middle study dose | Highest study dose (10 mg) |
|---|---|---|---|---|
| Oedema (swollen ankles)5 | 1% | 2% | 3% | 11% |
| Palpitations5 | 1% | 1% | 1% | 5% |
| Dizziness5 | 2% | 1% | 3% | 3% |
| Flushing5 | 0% | 1% | 1% | 3% |
Discontinuation because of side effects about 1.5 percent versus 1 percent with placebo. Oedema was more common in women than in men (14.6 versus 5.6 percent).5
Storage
Store dry, at room temperature and protected from light. Keep out of reach of children.
