Q.Why should not medicines be taken without consulting doctors ?

A drug is designed to interact with a specific target molecule (enzyme or receptor) to produce a desired effect, but this selective, beneficial interaction generally holds only within a particular concentration/dose range.

If medicines are taken without a doctor's guidance:

• Wrong dosage — too high a dose can cause the drug to interact with additional, unintended biomolecules (off-target effects), producing toxicity or serious side effects; too low a dose may be ineffective.
• Drug interactions — combining medicines without medical knowledge can cause dangerous interactions between drugs.
• Individual patient factors — age, body weight, existing conditions, allergies and other medications all affect what dose and drug are safe, and only a doctor can properly evaluate these. …

Reason from the target-molecule model of drug action: correct dose = correct effect, wrong dose = off-target harm. Add pa …

• Giving a generic "medicines can be dangerous" answer without connecting it to dose-dependent target interaction. …