Advertisements for clemastine (Tavist-1 - Sandoz), an ethanolamine oral antihistamine, have recently appeared on television and in major newspapers in the USA. Clemastine is an old drug (Medical Letter, 21:24, 1979) that has now become available without a prescription.

Cetirizine (Zyrtec - Pfizer), a histamine H 1 -receptor antagonist, has been approved by the US Food and Drug Administration for treatment of seasonal allergic rhinitis, perennial allergic rhinitis and chronic idiopathic urticaria in adults and children more than 12 years old.

The physiologic changes that occur with aging can affect the pharmacokinetics and pharmacodynamics of many prescription and over-the-counter drugs, increasing the likelihood of adverse effects.

The FDA has issued new warnings about the use of the opioid analgesics codeine and tramadol in children, particularly those <12 years old, and in breastfeeding women due to concerns about the risk of respiratory depression and death. The FDA previously issued warnings about these drugs in 2013 and 2015.

View the Inhibitors and Inducers of CYP Enzymes, P-Glycoprotein, and Other Transporters tables

The Drug Enforcement Administration (DEA) has reclassified all hydrocodone combination products as schedule II controlled substances; they were previously classified as schedule III. Hydrocodone alone (Zohydro ER) is already a schedule II controlled substance.