The complete safety profile of a drug cannot be made before marketing because of the limited scope of the controlled clinical trials. Postmarketing surveillance (PMS) is the collection and analysis of information about a drug after it has been marketed. A PMS system ideally must be able to detect a rare event, determine its incidence, and validate the causality. Because an ideal system has not been devised, a combination of methods is used. The advantages and limitations of various methods of adverse drug reaction (ADE) reporting are described, and problems and concerns associated with ADE reporting are discussed. Postmarketing surveillance will continue to benefit from spontaneous reporting of ADEs by clinicians (ie, literature reports, reports to manufacturers and national regulatory agencies) to detect rare events and will be complemented by the selective use of formal PMS methods in appropriate circumstances. Increased clinician awareness of serious, potentially drug-related events together with comprehensive and complete reporting of these events will begin to address the problems of underreporting, assessment of causality, and misclassification of events.
Twenty-four healthy adult male volunteers were randomly assigned to one of two rimantadine regimens. The 12 volunteers assigned to regimen 1 orally received a single 100-mg rimantadine tablet followed 5 days later by 100 mg of rimantadine twice a day for 10 days. Volunteers assigned to regimen 2 ingested a single 100-mg rimantadine tablet followed 5 days later by 100 mg once a day for 10 days. The results of the study suggest that the pharmacokinetics of rimantadine are linear and accumulation of the drug during repetitive multiple doses is predictable.