Drug-induced hair colour changes.

Drug-induced hair colour changes are not a common adverse effect from medications. A wide variety of drugs have been implicated in causing hair colour changes but very few have data to support a true relationship. Of the drugs reported, chloroquine and cancer chemotherapeutic agents have the best evidence to support an association. Other drugs, such as p-aminobenzoic acid, calcium pantothenate, anthralin, chinoform, mephenesin, minoxidil, propofol, valproic acid, and verapamil await confirmatory data. Drug-induced causes should be considered in any patient with unexplained hair colour changes.