Zafirlukast (za fir loo kast; Accolate - Zeneca), the first leukotriene receptor anta-gonist approved by the US Food and Drug Administration, is now being heavily promoted for oral maintenance treatment of chronic asthma in patients more than 12 years old. It is not recommended for treatment of acute asthma.

Brivaracetam (Briviact – UCB), an analog of levetiracetam (Keppra, and others), has been approved by the FDA for adjunctive treatment of partial-onset seizures in patients ≥16 years old. New drugs for epilepsy are often approved initially only as adjunctive treatment for partial seizures.

Fluconazole (Diflucan - Roerig), an antifungal azole, was recently approved by the US Food and Drug Administration for oral and intravenous (IV) treatment of cryptococcal meningitis and various forms of candidiasis. Both cryptococcal meningitis and candidiasis occur frequently in patients with AIDS, organ transplants, or cancer.

Clozapine (Clozaril - Sandoz), an antipsychotic drug, was first marketed in the USA three years ago (Medical Letter, 32:3, 1990). Because of its hematological toxicity, the US Food and Drug Administration approved the drug only for patients with schizophrenia who cannot tolerate or do not respond to standard antipsychotic drugs.

Imatinib mesylate (STI-571; Gleevec - Novartis), an oral tyrosine kinase inhibitor, has received accelerated approval from the FDA for treatment of all phases of chronic myeloid leukemia (CML) after interferon has failed.

Modafinil (Provigil - Cephalon; Alertec - Draxis in Canada), first approved by the FDA in 1999 for treatment of excessive daytime sleepiness associated with narcolepsy (Medical Letter 1999; 41:30), has now also been approved for treatment of patients with excessive sleepiness due to obstructive sleep apnea/hypopnea syndrome (OSAHS) or shift work sleep disorder (SWSD) (DSM-IV, text revision, Washington, DC: American Psychiatric Association, 2000, page 622).

Serious adverse interactions between drugs continue to be reported. Many of these are due to inhibition or induction of cytochrome P450 (CYP) enzymes, particularly CYP3A4. CYP3A is thought to be involved in the metabolism of more than 50 percent of currently prescribed drugs.2 CYP3A4, which is more abundantly expressed than CYP3A5, accounts for most CYP3A activity in vivo.

The FDA recently cleared the AmpliChip CYP450 Test (Roche), which analyzes blood-derived DNA to detect genetic variations in the activity of cytochrome P450 (CYP) enzymes CYP2D6 and CYP2C19 and determines the metabolizer status of the patient. The test is intended to help guide clinicians in prescribing individualized drug therapy. About 25% of all drugs, including many antidepressants and antipsychotics, are substrates of either CYP2D6 or CYP2C19. The test is being promoted initially to psychiatrists.

The FDA is advising health care professionals not to prescribe valproate sodium (Depacon), valproic acid (Depakene, Stavzor, and generics) or divalproex sodium (Depakote, Depakote ER, and generics) for migraine prevention in pregnant women because a recently published study showed that IQ scores are decreased in children of mothers who took these drugs during pregnancy. The FDA recommends avoiding valproate altogether, if possible, in women of childbearing age.1VALPROATE — Valproic acid and divalproex sodium dissociate to valproate in the GI tract. Valproate is considered the drug of choice...

Pantoprazole, the fourth benzimidazole proton pump inhibitor to become available in the United States, has been marketed for short-term oral treatment of erosive gastroesophageal reflux disease (GERD).