Therapeutic Drug Monitoring

Key points

• Digoxin: take at least 6 hours post-dose (to ensure adequate distribution).
• Lithium: range 0.5–1.0 mmol/l — take 12 hours post-dose.
• Cyclosporine: trough level immediately before dose.
• Phenytoin: trough level immediately before dose.
• Mnemonic DL-CP: Digoxin · Lithium · Cyclosporine · Phenytoin.