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.

L-methylfolate (Deplin — Pamlab) is a “medical food” marketed for adjunctive use in depression or schizophrenia in patients with suboptimal folate levels. It is available only by prescription.

The 1990 labeling for Norpramin, the Merrell Dow brand of the tricyclic antidepressant desipramine, reports the occurrence of sudden death in an eight-year-old child treated with the drug. Desipramine is also available as Pertofrane (Rorer) and generically.

Alzheimer's disease (AD) is the most common cause of dementia, but cognitive decline is also associated with other neurological conditions such as Parkinson's disease, dementia with Lewy bodies, vascular dementia, and frontotemporal dementia.

Fluvoxamine maleate, a selective serotonin reuptake inhibitor (SSRI) that has been available for many years in an immediate-release formulation (Luvox, and others) for treatment of obsessive-compulsive disorder (OCD) in children and adults, has now been approved by the FDA in an extended-release formulation (Luvox CR - Jazz Pharmaceuticals) for treatment of OCD and social anxiety disorder (SAD) in adults.

The FDA has approved an extended-release oral suspension formulation of amphetamine (Adzenys ER – Neos) for treatment of attention deficit hyperactivity disorder (ADHD) in patients ≥6 years old. The same extended-release amphetamine product is available as an orally disintegrating tablet and is marketed as Adzenys XR-ODT. Another extended-release oral suspension formulation of amphetamine, Dyanavel XR, was approved earlier.

The FDA has approved the oral second-generation antipsychotic drug brexpiprazole (Rexulti – Otsuka/Lundbeck) for once-daily treatment of agitation associated with dementia due to Alzheimer's disease (AD). Brexpiprazole is the first drug to be approved in the US for this indication. It is also approved for treatment of schizophrenia and as an adjunct to antidepressants for treatment of major depressive disorder.

Acute toxic reactions to drugs of abuse continue to be important problems. Some patients may have mixed intoxications with complex combinations of signs and symptoms.

Many readers have asked the Medical Letter to evaluate St. John's wort, an herbal extract now widely sold in health food stores and pharmacies, for its effectiveness and safety in the treatment of depression. St. John's wort is licensed in Germany for treatment of anxiety, depression and insomnia. In the USA, it is considered a dietary supplement and has not been evaluated by the FDA.

The FDA recently approved the monoamine oxidase inhibitor (MAOI) selegiline in a transdermal (patch) formulation (Emsam - Bristol-Myers Squibb/Somerset) for treatment of major depressive disorder. Selegiline is also available in an oral formulation (Eldepryl, and others) for treatment of Parkinson's disease.