Warfarin sodium (Coumadin, and others) and other coumarin anticoagulants prevent thrombosis, but patient response is highly variable and overanticoagulation can lead to hemorrhage. Genotyping patients for single nucleotide polymorphisms (SNPs) that affect coumarin metabolism and sensitivity may help clinicians estimate the therapeutic warfarin dose. The FDA has added a note to warfarin labeling recommending lowrange doses for patients with such genetic variations. Commercial tests for these variants are now available and cost about $500 per test.

Most colorectal cancers arise from localized adenomatous polyps in a process that may take 10 years or more. Early detection and removal of a precancerous colonic lesion (polyp) can prevent cancer from developing.

The US Food and Drug Administration recently approved ''Treatment IND';'; (investigational new drug) protocols for Exosurf (Burroughs Wellcome) and Survanta (Ross), two preparations of surfactant used for prevention and treatment of the respiratory distress syndrome (RDS) in premature newborn infants. Consequently, these drugs will be available to virtually every level-ΙΙΙ neonatal intensive-care unit in the USA.

Pegademase (Adagen - Enzon), bovine adenosine deaminase (ADA) conjugated with polyethylene glycol (PEG), was recently approved by the US Food and Drug Administration as an 'orphan drug' for treatment of severe combined immunodeficiency disease (SCID). SCID due to inherited deficiency of ADA occurs in less than one per million births; until recently, without extraordinary isolation measures, it was usually fatal before the age of two.

Isradipine (DynaCirc - Sandoz), a dihydropyridine calcium-channel blocker chemically related to nicardipine (Cardene) and nifedipine (Procardia, and others), was recently approved by the US Food and Drug Administration for oral treatment of hypertension.

Methadone, an opioid agonist that can be taken orally, has been used for maintenance treatment for many years in the USA (DM Novick et al, Drug Alcohol Depend, 33:235, 1993). Last year, the US Food and Drug Administration approved the distribution and use of L-alpha-acetyl-methadol (LAAM; ORLAAM - Bio Development Corporation, McLean, VA), a long-acting congener of methadone. LAAM, like methadone, will be available for this indication only through federal and state-regulated treatment programs.

Donepezil hydrochloride (Aricept - Eisai), a piperidine-based acetylcholinesterase inhibitor, is now being marketed for oral treatment of cognitive symptoms in patients with mild to moderate dementia due to Alzheimer's disease. Donepezil is the second drug approved for this indication; tacrine hydrochloride (Cognex), also an acetylcholinesterase inhibitor, has been available in the USA for four years (Medical Letter, 35:87, 1993).

Electronic cigarettes, also called e-cigarettes, are advertised as a safer, more convenient, and socially acceptable alternative to smoking tobacco cigarettes. Widely available in retail stores and on the Internet, their use has been increasing over recent years, primarily among smokers, but also among non-smokers.

A reader expressed concern that a statement in our article Naloxone (Narcan) Nasal Spray for Opioid Overdose (Med Lett Drugs Ther 2016; 58:1) might be misleading. We stated that heroin has a half-life of 2-6 minutes, which is correct, but heroin is a prodrug that is rapidly metabolized to 6-acetylmorphine and morphine. The risk of respiratory depression is related to those active metabolites, and it may persist well beyond the clearance of heroin from the blood.

The FDA has required manufacturers of the oral P2Y₁₂ platelet inhibitors clopidogrel (Plavix, and generics), prasugrel (Effient, and generics), and ticagrelor (Brilinta) to warn in the product labels that the absorption of these drugs may be delayed or reduced when taken with an opioid agonist.