Paracetamol & Ibuprofen Tracker

Timing, limits & advice

The phases are illustrative. “Coming up” means the model is rising; “stable / near peak” means at least 90% of the model’s single-dose peak; “coming down” means it is declining. That 90% band is a display choice, not a clinically established stable period. The phase describes the latest dose, while the graph adds all recorded doses of the same medicine.

For standard oral ibuprofen, product information reports peak blood levels around 45 minutes on an empty stomach or 1–2 hours with food, with a half-life around 2 hours. Paracetamol peaks around 30 minutes–2 hours, with a reported half-life of 1–4 hours. Food, formulation and individual health change these timings. Blood levels do not directly measure pain relief, and a falling curve does not tell you to take another dose.

The graph uses a simplified absorption-and-elimination model: a 2-hour half-life for both medicines and approximate peaks at 49 minutes for paracetamol and 87 minutes for ibuprofen. These assumptions sit within the published ranges; the model is not validated for individual dosing. It has no guaranteed onset, plateau or time when a medicine is completely gone.

• Ibuprofen: take with or after food. Use the smallest effective dose for the shortest time; do not use for more than 10 days without medical advice. Avoid during pregnancy unless advised by a clinician. Ask a pharmacist first if you have ulcers or bleeding, kidney, liver or heart problems, asthma/NSAID reactions, dehydration, or take blood thinners, aspirin or other interacting medicines. Do not combine with other NSAIDs such as naproxen or diclofenac.
• Paracetamol: check cold/flu and combination remedies for hidden paracetamol. Ask about lower limits if under 50 kg or if you have liver/kidney disease or heavy alcohol use. Do not use for more than 3 days without medical advice.
• Using both: adults can take them together if each is suitable, but try one on its own first. Keep each medicine’s dose spacing and limits separate. There is no extra cross-medicine waiting period in this tracker.
• If you took too much: seek urgent medical or poison-service advice, even if you feel well, particularly with paracetamol. Do not wait for this graph. Seek emergency help for breathing difficulty or throat swelling; get urgent help for vomiting blood or black, tar-like stools.

Sources checked 22 October 2026: NHS ibuprofen guidance · NHS paracetamol guidance · Ibuprofen product information, sections 4 & 5.2 · Paracetamol product information, sections 4 & 5.2. Your local packet may give different limits; use those if stricter.