THERAPEUTICS

Brands

• Sibelium

Generic?

• Yes

Class

• Calcium channel blocker, antihistamine

Commonly Prescribed for

(FDA approved in bold)

• Migraine prophylaxis

• Hemiplegic migraine prophylaxis

• Vasospasm in subarachnoid hemorrhage

• Adjunctive drug for epilepsy

• Vertigo

• Alternating hemiplegia of childhood

• Gilles de la Tourette syndrome

• Tinnitus

How the Drug Works

• Migraine/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.

• Prevention of cortical spreading depression may be one mechanism of action for all migraine preventives

• May also interact with other neurotransmitters, and may inhibit the synthesis and release of nitric oxide

• The drug also appears to act by blocking dopamine D2 receptors in a manner similar to antipsychotics

How Long Until It Works

• Migraines may decrease in as little as 2 weeks, but can take up to 2 months to see full effect

If It Works

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

If It Doesn't Work

• Increase to highest tolerated dose

• Migraine: 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

• Migraine: for some patients with migraine, low-dose polytherapy with 2 or more drugs may be better tolerated and more effective than high-dose monotherapy. May use in combination with AEDs, antidepressants, natural products, and non-medication treatments, such as biofeedback, to improve headache control

Tests

• Monitor ECG for PR interval

ADVERSE EFFECTS (AEs)

How the Drug Causes AEs

• Direct effects of calcium receptor antagonism and other CNS receptors. Antihistaminic properties likely cause weight gain and sedation. D2 blockade can cause movement disorders

Notable AEs

• Sedation, depression, weight gain are most problematic

• Nausea, dry mouth, gingival hyperplasia, weakness, muscle aches, and abdominal pain can occur