Introduction
The medication history is a standalone OSCE station and a compulsory part of every history-taking station. A complete drug history goes beyond reading a prescription chart — it covers dose, route, indication, adherence, side effects, OTC medications, herbal remedies, and a detailed allergy characterisation.
💎 Clinical Pearl
Ask open questions first: "Can you tell me all the medicines you take, including anything you buy yourself?" Then work through each one systematically. Never assume a patient knows their drug names or doses — prompt them with descriptions.
DRUGS Mnemonic
🧠 Mnemonic
DRUGS — Dose, Route, Use, Gaps, Side effects
- Dose: exact dose and frequency for each medication
- Route: oral, inhaled, topical, IV, patch, injection
- Use: indication — why is the patient taking it?
- Gaps: missed doses, recently stopped medications and why
- Side effects: any problems the patient attributes to their medications
Complete Medication History Framework
Step 1: Opening
"Can you tell me all the medicines you take? That includes anything from the pharmacy or supermarket, any vitamins or herbal products, and anything you only take occasionally."
Step 2: For Each Drug, Ask DRUGS
| Component | Example question |
|---|---|
| Dose | "What dose do you take and how often?" |
| Route | "Do you take it as a tablet, inhaler, or injection?" |
| Use | "What is this medication for?" |
| Gaps | "Do you ever miss doses?" |
| Side effects | "Have you noticed any side effects from it?" |
Step 3: OTC, Herbal, PRN, and Contraceptives
- Analgesics: paracetamol, NSAIDs, codeine (frequently bought OTC and omitted)
- Vitamins and supplements: iron, B12, folic acid, vitamin D
- Herbal remedies: St John's Wort, ginkgo
- Contraceptive pill and hormone replacement therapy (frequently omitted)
- Recreational drugs
⚠️ Red Flag
St John's Wort is a potent CYP450 inducer. It reduces the effectiveness of warfarin, the combined oral contraceptive, antiretrovirals, ciclosporin, and many other drugs. Always ask specifically about herbal remedies.
Allergy History — DRIED Mnemonic
🧠 Mnemonic
DRIED — Drug name, Reaction description, Investigation, Exact timing, Documented
- Drug: exact name — was it amoxicillin specifically or just penicillin in general?
- Reaction: describe precisely — rash, anaphylaxis, GI upset? Distinguish true allergy from intolerance
- Investigation: was it formally investigated or allergy-tested?
- Exact timing: how long after the drug before the reaction began? Immediate = IgE-mediated
- Documented: is it in the medical notes and on the drug chart?
Adherence Assessment
Non-adherence is the most common reason for treatment failure. Ask non-judgementally:
"Many people find it difficult to take medicines every day — is that ever a problem for you?"
Barriers to explore: side effects, complex regimens, cost, health beliefs, cognitive impairment, physical difficulty (e.g. opening blister packs in arthritis).
Polypharmacy Red Flags
| Number of medications | Risk |
|---|---|
| 5+ | Polypharmacy — increased drug interaction and falls risk |
| 10+ | Hyperpolypharmacy — consider formal medication review |
High-Risk Drug Combinations to Know
| Combination | Risk |
|---|---|
| Warfarin + NSAIDs | Major bleeding (GI, intracranial) |
| ACE inhibitor + potassium-sparing diuretic | Hyperkalaemia |
| Metformin + IV contrast | Lactic acidosis (withhold before and after IV contrast) |
| SSRI + tramadol | Serotonin syndrome |
| Lithium + NSAIDs | Lithium toxicity |
| Statin + clarithromycin | Myopathy and rhabdomyolysis |
"What does DRUGS stand for in a medication history?"
DRUGS: Dose (exact dose and frequency), Route (how the medication is taken), Use (indication), Gaps (missed doses or recently stopped medications), Side effects (adverse effects attributed to the medication). Work through DRUGS for each medication systematically.
"How do you characterise a drug allergy using DRIED?"
DRIED: Drug name (confirm the exact drug), Reaction description (rash, anaphylaxis, GI upset — distinguish true allergy from intolerance), Investigation (whether it was tested), Exact timing (how long after the dose before the reaction — immediate IgE-mediated vs delayed), Documented (recorded in notes and on drug chart).
"Why is it important to ask about OTC and herbal medicines?"
Patients do not consider OTC or herbal products as medicines and omit them unprompted. NSAIDs worsen renal function and interact with anticoagulants. St John's Wort is a potent CYP450 inducer that reduces efficacy of warfarin, the combined pill, antiretrovirals, and ciclosporin. Always ask specifically.
"What are the signs of poor medication adherence and how do you approach it?"
Signs include subtherapeutic drug levels, failure of disease control at appropriate doses, and discrepancy on pill count. Approach non-judgementally — acknowledge that taking medicines regularly is difficult. Explore specific barriers (side effects, forgetfulness, cost, health beliefs) and simplify regimens where possible. Refer to a pharmacist for a medicines use review.
Related guides: [Prescribing Safety OSCE](/blog/prescribing-safety-osce) | [How to Take a Cardiology History OSCE](/blog/how-to-take-a-cardiology-history-osce) | [Blood Results Interpretation OSCE](/blog/blood-results-interpretation-osce)