Expansion
Working backwards from the symptom to the likely drug
Mnemonic
DISCO for gynaecomastia:
- D - Digoxin
- I - Isonaizid, and spironolactone
- S - Spironolactone
- C - Cimetidine, cannabis
- O - Oestrogens, ketoconazole
Other high yield groupings:
- Gum hypertrophy: phenytoin, ciclosporin, nifedipine
- Pulmonary fibrosis: amiodarone, methotrexate, bleomycin, nitrofurantoin, busulfan
- Photosensitivity: amiodarone, tetracyclines, thiazides, sulphonamides
- Drug induced lupus: hydralazine, isoniazid, procainamide, phenytoin, with anti-histone antibodies
- Prolonged QT: amiodarone, sotalol, macrolides, quinolones, antipsychotics, citalopram, methadone, ondansetron
- Serotonin syndrome: SSRIs with tramadol, linezolid, triptans, MAOIs
Expansion
| Effect | Common drug causes |
|---|---|
| Gynaecomastia | Spironolactone, digoxin, cimetidine, antipsychotics, finasteride |
| Gingival hyperplasia | Phenytoin, ciclosporin, nifedipine |
| Hyponatraemia | Thiazides, SSRIs, carbamazepine, PPIs |
| Hyperkalaemia | ACE inhibitors, ARBs, spironolactone, trimethoprim, NSAIDs |
| Photosensitivity | Tetracyclines, amiodarone, thiazides, quinolones |
| Pulmonary fibrosis | Amiodarone, bleomycin, methotrexate, nitrofurantoin |
| Peripheral neuropathy | Isoniazid, metronidazole, vincristine, amiodarone, phenytoin |
| Cholestasis | Co-amoxiclav, flucloxacillin, chlorpromazine, anabolic steroids |
| Angioedema | ACE inhibitors |
| Dry cough | ACE inhibitors |
| Tinnitus and deafness | Aminoglycosides, aspirin, loop diuretics, cisplatin |
| QT prolongation | Macrolides, quinolones, antipsychotics, ondansetron, methadone |
| Urinary retention | Antimuscarinics, tricyclics, opioids |
Two practical habits follow. First, when a new symptom appears, review the drug chart before ordering tests. Second, be alert to the prescribing cascade, in which a drug side effect is treated with another drug rather than recognised, as when calcium channel blocker ankle oedema is treated with a diuretic.