Management of ADRs
Management of ADRs
Clinical management of ADRs begins with avoidance of predictable reactions. Dose-dependent and predictable ADRs (due to the pharmacological activity of the drug) can be avoided by appropriate dose selection (step 4 of the 6STEP, considering patient characteristics).
Considerations include starting with a low dose, renal function testing, genotype testing, etc. In order to decrease the risk of an adverse effect, other preventative medication can be added. For example, a proton pump inhibitor can be added to chronic treatment with an NSAID for the prevention of GI bleeding.
Once an ADR has occurred, it is important to know the type. When an ADR is related to the pharmacological mechanism of action, reduction of dose might be sufficient management. If the ADR persists, substitution with an alternative drug with a different mechanism of action or a more specific pharmacological action can be tried. When an alternative drug is not available, a risk-benefit decision needs to be taken. It is sometimes necessary to continue treatment, adding drugs for the relief of adverse symptoms.
When the ADR is due to a idiosyncratic or allergic reaction, the only definitive option is to stop the medication. The patient should never use the drug again. Sometimes, the reaction is tolerable when the dose is lowered. An alternative drug with a different chemical structure can be tried instead. Usually, the symptoms of this type of ADR are severe and require additional treatment.
In case of serious toxic effects, pharmacokinetic approaches can be applied in order to minimise damage. Prevention of absorption and enhancement of metabolism and/or elimination (rapidly getting rid of the drug) are common approaches.
Another—purely pharmacological—method is to block the action of the drug by blocking its receptor. If available, an antidote should be administered in life-threatening situations.
Metabolic pathway alternatives can be exploitedby supplying certain substrates, allowing other metabolic pathways than the drug-inhibited one.
If a patient suffers from organ-directed toxicity, management can be aimed at saving the specific organ. E.g. the management of nephrotoxicity includes single daily dose, reduction of the course of treatment, and avoidance of concurrent administration of nephrotoxic drugs.