Sustiva (Efavirenz)
Purpose of Medication and Method of Action
Sustiva is an antiviral drug specifically approved for the treatment of infections due to the human immunodeficiency virus (HIV). It acts by binding to and inhibiting an enzyme required for replication of the HIV virus, reverse transcriptase.
Because its is not structurally like a nucleoside inhibitor (such as AZT) it is called a non-nucleoside reverse transcriptase inhibitor (NNRTI). Sustiva should never be used alone to treat HIV+ persons.
Side Effects
The most clinically significant side effects are those of the central nervous system and occur in as many as 50% of patients. Those include dizziness, impaired concentration, abnormal dreams and a change in sleep behavior (both sleepiness and insomnia). The central nervous system side effects frequently resolve in the first 30 days of therapy. The other common side effect is a skin rash seen in 25-30% of patients. Should this occur, antihistamines and/or steroids may hasten their resolution and permit continued therapy.
Drug Interactions
The most significant interactions are with the protease inhibitors also use to treat HIV infections. The most significant of these is a 50% decrease in blood levels of Fortovase. Other potentially important interactions exist with ergot derivatives, cisapride, astemizole, and triazolam where blood levels of those drugs can be increased when Sustiva is used at the same time.
Cautions and Contraindications
None
Usual Dose
The usual dose is 600 mg (3-200 mg) tablets once a day. Taking the medication at bedtime may reduce the central nervous system side effects.
Patient Medication Information
These information sheets do not list all known side effects of the medications, only the most common side effects. For a complete list of side effects please contact your local pharmacy or the actual drug manufacturing company.