How long do medication side effects last?
Last updated September 3, 2026.
One to two weeks for most start-up effects: the NHS says it for antidepressants - most ease after a couple of weeks as your body adjusts - and the arc holds for blood pressure drugs and metformin too. Three shapes: the fading arc (worst week one, gone by week three - the commonest); the persistent flat line (steady past a month is a dose or drug mismatch - adjust or switch, not endure); and the late arrival (omeprazole's magnesium dip past 3 months, statin aches weeks to months in) - new symptoms on an old drug still deserve mention. The absolute: anything looking like allergy - lip, tongue, or throat swelling, hives with breathing trouble - is an emergency, never a wait-it-out. Pymander is a free AI doctor, 24/7 by text, and can help you classify yours.
What to do
- Give mild start-up effects two weeks: the standard adaptation window.
- Past a month? Say so: persistence means adjust.
- New symptom on an old drug? Mention it: late arrivals exist.
- Allergy signs are the exception: emergency, not patience.
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