Vasodilator Characteristics
| Pharmacologic agent | Class | Mechanism of action | Dose | Duration | Infusion pump required | Half-life | Increase in coronary flow | Incidence of atrioventricular block (vasodilators) |
| Adenosine | Direct coronary artery vasodilator | Nonselective adenosine receptor agonist | 140 μg/kg/min (up to 125 kg) | 6-min infusion with radiopharmaceutical injection at 3 min | Yes | <10 s | 3.5–4 times baseline | 8% of studies |
| Dipyridamole | Indirect coronary artery vasodilator | Nonselective adenosine receptor agonist | 142 μg/kg/min (up to 125 kg) | 4-min infusion with radiopharmaceutical injection at 3–5 min afterward | No | 30–45 min | 3.8–7 times baseline | 2% of studies |
| Regadenoson | Direct coronary artery vasodilator | Selective A2A receptor agonist | 400 μg | 10-s infusion with radiopharmaceutical injection at 20–30 s afterward | No | Initial phase, 2–4 min; intermediate, 30 min; terminal, 2 h | 2.5 times baseline | 3% of studies |
| Dobutamine | Inotropic agent | Direct β1 and β2 stimulation | 3-min incremental stages: 10, 20, 30, 40 μg/kg/min | Until target heart rate or 12-min maximum is reached | Yes | <3 min | 2–3 times baseline | Not applicable |