THERAPEUTICS

Brands

• Calan, Cordilox, Securon, Verapress, Vertab, Univer, Covera-HS, Verelan, Isoptin SR

Generic?

• Yes

Class

• Calcium channel blocker

Commonly Prescribed for

(FDA approved in bold)

• Angina (vasospastic, unstable, or effort associated)

• Essential hypertension

• Paroxysmal supraventricular tachycardia, atrial fibrillation/flutter (IV formulation, immediate-release tablet)

• Prophylaxis of hemiplegic migraine or migraine with prolonged aura

• Cluster headache prophylaxis

• Peyronie's disease, plantar fibromatosis, Dupuytren's disease (gel)

How the Drug Works

• Cluster: proposed prior mechanisms included inhibition of smooth muscle contraction preventing arterial spasm and hypoxia, prevention of vasoconstriction or platelet aggregation, and alterations of serotonin release and uptake

• Voltage-gated calcium channels mediate calcium influx and are important in regulating neurotransmitter and hormone release

How Long Until It Works

• Migraines: may decrease in as little as 2 weeks, but can take up to 3 months on a stable dose to see full effect

• Cluster: usually effective in weeks

If It Works

• Migraine: goal is a 50% or greater reduction in migraine frequency or severity. Consider tapering or stopping if headaches remit for more than 6 months or if considering pregnancy

• Cluster: reduction in the severity or frequency of attacks

If It Doesn't Work

• Increase to highest tolerated dose

• Migraine/cluster: address other issues, such as medication overuse, other coexisting medical disorders, such as anxiety, and consider changing to another agent or adding a second agent

Best Augmenting Combos for Partial Response or Treatment-Resistance

• Cluster: at the start of the cycle can use a corticosteroid slam and taper. Lithium, topiramate are effective preventive medications for cluster patients

Tests

• At higher doses, monitor ECG for PR interval

ADVERSE EFFECTS (AEs)

How the Drug Causes AEs

• Direct effects of calcium receptor antagonism, slowing of AV conduction

Notable AEs

• Bradycardia, hypotension, weakness, headache

• Constipation, nausea, myalgia

• Allergic rhinitis, ankle edema, gingival hyperplasia

• First-degree AV block

• Upper respiratory infection, flu-like syndrome