| Indication | For the treatment of hypertension, angina, and cluster headache prophylaxis. |
| Pharmacodynamics | Verapamil is an L-type calcium channel blocker that also has antiarrythmic activity. The R-enantiomer is more effective at reducing blood pressure compared to the S-enantiomer. However, the S-enantiomer is 20 times more potent than the R-enantiomer at prolonging the PR interval in treating arrhythmias. |
| Mechanism of action | Verapamil inhibits voltage-dependent calcium channels. Specifically, its effect on L-type calcium channels in the heart causes a reduction in ionotropy and chronotropy, thuis reducing heart rate and blood pressure. Verapamil's mechanism of effect in cluster headache is thought to be linked to its calcium-channel blocker effect, but which channel subtypes are involved is presently not known. |
| Absorption | 90% |
| Volume of distribution | Not Available |
| Protein binding | 90% |
| Metabolism | Not Available |
| Route of elimination | Approximately 70% of an administered dose is excreted as metabolites in the urine and 16% or more in the feces within 5 days. About 3% to 4% is excreted in the urine as unchanged drug. |
| Half life | 2.8-7.4 hours |
| Clearance | Not Available |
| Toxicity | LD50=8 mg/kg (i.v. in mice) |