| Indication | Target Level | Typical Oral Dose | Notes |
|---|
| Heart Failure (systolic) | 0.5–0.9 ng/mL | 0.0625–0.125 mg QD | Lower levels preferred in HF |
| AF Rate Control | 0.8–2.0 ng/mL | 0.125–0.25 mg QD | Titrate to resting HR <80 bpm |
| Toxicity threshold | > 2.0 ng/mL | High risk of toxicity — check K&sup+;, Mg²&sup+; |
IBW male = 50 + 2.3×(ht_in−60); female = 45.5 + 2.3×(ht_in−60)
CrCl (Cockcroft-Gault) using IBW
Vd ≈ 3.8–7 L/kg (non-CHF) or 4.5 L/kg (CHF)
CL (mL/min/70kg) = 1.303×CrCl + CL_nr [40 non-CHF; 20 CHF]
t½ = 0.693 × Vd / CL; Maintenance = Css × CL × 24
Toxicity signs: Nausea, vomiting, visual changes (yellow-green halos), bradycardia, AV block. Toxicity increased by hypokalemia, hypomagnesemia, hypothyroidism, renal impairment. Draw level ≥6h post-oral dose (ideally trough). Interactions: amiodarone, clarithromycin, verapamil increase levels.
