THERAPEUTICS

Brands

• Inderal, Inderal-LA, InnoPran XL, Hemangeol

Generic?

• Yes

Class

• β-blocker

Commonly Prescribed for

(FDA approved in bold)

• Migraine prophylaxis

• Essential tremor

• Hypertension

• Angina pectoris due to coronary atherosclerosis

• Cardiac arrhythmias (including supraventricular arrhythmias, ventricular tachycardia, digitalis intoxication)

• Myocardial infarction (MI)

• Hypertrophic subaortic stenosis

• Pheochromocytoma

• Akathisia (antipsychotic induced)

• Parkinsonian tremor

• Congestive heart failure

• Tetralogy of Fallot

• Hyperthyroidism (adjunctive)

• Generalized anxiety disorder

• Post-traumatic stress disorder

• Prevention of variceal bleeding

How the Drug Works

• Migraine: proposed mechanisms include inhibition of adrenergic pathway, interaction with serotonin system and receptors, inhibition of nitric oxide production, normalization of contingent negative variation, and inhibition of thalamic trigeminovascular neurons. Prevention of cortical spreading depression may be one mechanism of action for all migraine preventives

• Tremor: effectiveness is likely due to peripheral β2-receptor antagonism

How Long Until It Works

• Migraines: within 2 weeks, but can take up to 3 months on a stable dose to see full effect

• Tremor: within days

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 considering pregnancy

• Tremor: reduction in the severity of tremor, allowing greater functioning with daily activities and clearer speech

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 drug or adding a second drug

• Tremor: coadministration with primidone up to 250mg/day can augment response. Second-line medications include benzodiazepines such as clonazepam, gabapentin, topiramate, methazolamide, nadolol, and botulinum toxin (useful for voice and hand tremor). For truly refractory patients, thalamotomy and deep brain stimulation of the ventral intermediate nucleus of the thalamus are options

• Alternatives for tremor include hand weights and eliminating caffeine. Low doses of alcohol reduce tremor, but are not generally recommended