Drug tolerability versus drug safety.

Drug tolerability and drug safety are sometimes used interchangeably, but they represent somewhat different concepts. This editorial examines the differences between drug tolerability and safety. A literature search was conducted on MEDLINE (PubMed) to assess the differences between drug tolerability and safety. Drug tolerability is predominantly dependent on patients' subjective experiences, whereas drug safety is determined by a carefully regulated process based on objective measures. For a drug to be useful, it must be tolerable and safe.