Nabilone (Cesamet - Lilly), a synthetic cannabinoid chemically related to tetrahydrocannabinol (THC), the main active ingredient in marijuana, was recently marketed in the USA for oral treatment of nausea and vomiting associated with cancer chemotherapy. Oral THC itself, known generically as dronabinol (Marinol), is also commercially available as an antiemetic for cancer patients (Medical Letter, 27:97, 1985). Other drugs used for this purpose include metoclopramide (Reglan - Medical Letter, 24:67, 1982), prochlorperazine (Compazine; and others), haloperidol (Haldol; and others), and...

In the short time since fluoxetine (Prozac - Lilly) first became available in the USA (Medical Letter, 30:45, 1988), it has become the most frequently prescribed of all antidepressants. Some recent reports, however, have questioned its safety.

Aripiprazole (Abilify - Bristol-Myers Squibb/Otsuka), a quinolinone derivative, has been approved by the FDA for treatment of schizophrenia.

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.

An extended-release injectable formulation of the second-generation antipsychotic aripiprazole (Abilify) has been approved by the FDA (Abilify Maintena – Otsuka/Lundbeck) for once-monthly treatment of schizophrenia. It is the fourth second-generation antipsychotic to become available in a long-acting parenteral formulation. Long-acting parenteral antipsychotics, given at intervals of 2-4 weeks, are generally used for patients with a history of relapse due to poor adherence to oral maintenance therapy.

A recent supplement to the Journal of Clinical Psychiatry, titled "The Expert Consensus Guideline Series: Optimizing Pharmacologic Treatment of Psychotic Disorders," concluded that most experts endorsed use of second-generation (atypical) antipsychotics rather than first-generation drugs, with risperidone (Risperdal - Janssen) the top choice for first episodes, multiple episodes or switches from another drug (JM Kane et al, J Clin Psychiatry 2003; 64 suppl 12:5). The supplement was sponsored by Janssen.

Asenapine (Saphris - Schering-Plough), a dibenzo-oxepino pyrrole, has been approved by the FDA in a sublingual tablet formulation for acute treatment of schizophrenia and manic or mixed episodes associated with bipolar disorder. It is the sixth second-generation antipsychotic approved by the FDA for use in bipolar disorder.

Tetrabenazine (Xenazine - Ovation Pharmaceuticals), an old drug first synthesized 50 years ago for treatment of schizophrenia, was recently approved by the FDA for the treatment of chorea associated with Huntington's disease. It has been available in other countries for decades.

Changes caused by one drug in the absorption, distribution, metabolism or excretion of another may lead to a pharmacokinetic adverse drug interaction (DN Juurlink et al, JAMA 2003; 289:1652). Additive drug interactions, such as vasodilation caused by both sildenafil (Viagra) and nitrates, can also have adverse effects.

Dronedarone (Multaq - Sanofi-Aventis) has been approved by the FDA for oral treatment of atrial fibrillation and flutter. Amiodarone (Cordarone, and others) is the most effective drug for this indication, but has considerable toxicity.