After a patient has shared information about an adverse effect with their doctor or other health provider, it should be reported to the local or national pharmacovigilance centre (the great majority are not reported, which is a big problem). Here the likelihood of the medicine having caused the problem is further investigated. All possible causes are reviewed and the strength of the evidence is assessed, including other reports and material from reference works and journals.
Depending on the outcome, action may be taken - such as changing the way the drug is used, or even withdrawing it from the market. If the problem seems to be caused by sub-standard or counterfeit drugs, or there has been an interaction with another drug or substance, or the diagnosis or choice of drug was doubtful, other solutions are needed.
Reports of suspected adverse effects from member countries of the WHO Programme for International Drug Monitoring are sent to VigiBase, the WHO international database, managed by the UMC. There they are reviewed and analysed and the bigger picture of worldwide evidence begins to emerge.
Patient suffers adverse effects, apparently from a medicine
Patient reports problem to doctor or pharmacist or nurse OR patient reports directly to the local or national pharmacovigilance centre (UMC’s Take&Tell may help)
The problem is discussed with the health professional; possible causes are examined:
• Possibility of misdiagnosis
• Interactions with other medicines or foods or substances
• Non-adherence to advice for taking the medicine (missing doses, doubling up doses, wrong time of day, before or after food)
• Source and quality of medicine (is it genuine, counterfeit, sub-standard?)
Decision is made about what to do for the patient (maybe change dose or frequency or medicine)
Doctor, pharmacist or nurse reports problem to the local or national pharmacovigilance centre (spontaneous reporting)
The centre reviews the problem and any other reports about the drug (may also look at international data in WHO’s VigiBase)
The centre advises the national regulatory authority if the evidence suggests there is a problem
The regulatory authority may decide to take action*
The centre, in countries that are members of the WHO Programme for International Drug Monitoring, notifies WHO through UMC
UMC reviews the international data about the drug; if there seems to be a plausible link between the medicine and the adverse effect, UMC communicates its assessment of the problem as a signal to member countries and WHO.
Regulatory authorities around the world decide if action* should be taken.
If action is taken, information is published and made available to health professionals and patients.
The processes in the cycle may involve consultations among local, national or international colleagues and experts, manufacturers and members of the WHO Programme.
*Possible action: changing published information about the benefit-harm profile or other aspects of the medicine; restricting or amending the way it is used; withdrawing it from the market (very rare). Sometimes further research may be commissioned. Other causes of adverse effects (e.g. counterfeit medicines) may result in communications to patients or health professionals, public warnings, alerts, prosecutions or other measures.