All medicines can cause adverse reactions. An adverse reaction means a harmful and unintended response to a drug.
Adverse effects may occur, for example, as symptoms of the digestive tract, skin reactions, headache or fatigue. In general, adverse reactions to medicines are mild and often occur at the beginning of pharmacotherapy. However, sometimes due to adverse effects, pharmacotherapy must be discontinued or replaced. It is therefore advisable to know what kinds of adverse reactions it may have, whether they usually pass as the treatment continues and which adverse reactions require immediate contact with a doctor. This information can be found in the package leaflet.
For example, the prevalence of adverse reactions is often described in package leaflets as "very common", "general", "fairly rare" and "rare". A very common adverse reaction occurs in more than one in ten medicine users. General adverse reactions occur for 10-100 people in a thousand users, relatively rare adverse reactions for 1-10 in a thousand users and rare adverse reactions for 0.1-1 persons in a thousand users.
Information about the adverse effects of your medicine can be obtained from a doctor or pharmacist. Any adverse effects of the medicine are also described in the package leaflet.
Regulatory authorities and pharmaceutical companies worldwide collect information on adverse drug reactions. This way the knowledge on the safety of a particular drug gradually increases. Authorities are particularly interested in adverse reactions of new drugs, serious adverse reactions and new, previously unknown adverse reactions.
Read more about adverse reactions:
Monitoring the effects of medicinal treatment, Medicines Education Material by Fimea. Maintained by Terve koululainen, UKK-institute.