| Drug | Laboratory test | Therapeutic range |
|---|---|---|
| Digoxin | Digoxin | 0.8-2 mg/ml (SI: 1.0-2.6 mmol/L) |
| Phenytoin | Phenytoin | 10-20 mcg/ml (SI: 40-79 µmol/L) |
| Procainamide | Procainamide | 4-10 mcg/ml (SI: 17-42 µmol/L) |
| N-acetylprocainamide (NAPA) | 5-30 mcg/ml (combined procainamide and NAPA) | |
| Theophylline | Theophylline | 10-20 mcg/ml (SI: 44-111 µmol/L) |