Types of side effects
"A side effect is a harmful and / or unintended effect that accompanies the use of a drug in a usual dose for prevention, diagnosis or treatment of a disease or condition."
This definition comes from the World Health Organization. Unexpected effects of food, stimulants (alcohol and drugs) and consequences of an overdose are therefore not covered. The appearance of any side effect is not only the pharmacological action of the drug involved, but also patient-related factors.
Types of side effects
We differentiate between type A and type B reactions:
| Type A reactions |
Type B reactions |
| Drug-related |
Patient-related |
| Side effect is traceable to the pharmacological effect of the drug |
Side effect is not traceable to the pharmacological effect of the drug |
| Side effect is dose-dependent |
Side effect is not dose-dependent |
| Time relationship is suggestive |
Time relationship and mechanism are uncertain |
|
Adverse side effect is reproducible
|
Adverse side effect is usually not reproducible in other patients |
| Incidence is relatively high (> 1%) |
Incidence (frequency and background) is relatively low |
|
Reaction is usually seen in pre-registration studies
|
Reaction is usually only discovered after registration |
| |
Side effect is severe |
|
Example: bleeding when using aspirin
|
Example: Stevens-Johnson syndrome |