05.01.1.2 Monitoring of Adverse Effects

The adverse effects of drugs are monitored throughout clinical development, in Phase I, II, and III clinical trials. Phase IV of clinical trialling is post-marketing surveillance. The Therapeutic Goods Administration (TGA) regulates Australia’s medicines, medical devices, blood, tissues, and chemicals. In addition, the TGA has an Adverse Drug Reactions Advisory Committee (ADRAC), which is responsible for monitoring the adverse effects of drugs when they are widely available (Phase IV post-marketing surveillance). ADRAC relies on anecdotal reporting; Mrs Smith took drug A and developed a rash, i.e where there is no direct evidence of a link, and the finding could be coincidental. However, if lots of reports come in that drug A causes a rash, the evidence begins to mount. ADRAC relies on receiving voluntary reports from health professionals, which they monitor. If they think that the evidence linking a drug to an adverse effect is substantial, ADRAC may ask for intensive adverse event monitoring for that particular drug. ADRAC reports its findings in the Australian Adverse Drug Reactions Bulletin.

As a health professional, how do you tell whether a reaction is an adverse reaction of a drug? There are two general questions to ask the patient. First, does the reaction get worse with increasing doses of the drug? Most adverse effects of drugs are dose related – the more you take, the worse it gets. If this is the case, it indicates an adverse effect. Secondly, does the reaction go away when the drug is stopped? Many adverse effects are reversible on removing the drug. If this is the case, it also indicates an adverse effect of the drug.