| Diltiazem | Metoprolol |
Formulations | IV (bolus, continuous infusion), oral (IR, ER) | IV (push), oral (IR, ER) |
Onset of action (IV) | 3 minutes (bolus) | 20 minutes |
Duration of action (IV) | 1 - 3 hours (bolus), 0.5 - 10 hours (infusion) | 5 - 8 hours |
Half-life (IV) | 3 - 4 hours (bolus), 4 - 5 hours (infusion) | 2 - 6 hours |