| Drug | Fentanyl | Alfentanil | Morphine | Midazolam | Lorazepam | Diazepam | Propofol 1% | Fospropofol |
| Dose i.v. | Initial: 25–50 μg | Initial: 250 μg | Initial: 2.5 mg | Initial: 2–2.5 mg (0.5–1 mg in the elderly) | Initial dose: 1.5–2 mg | Initial dose: 5–10 mg | Initial: 10–50 mg titrated to effect | Initial: 6.5 mg·kg−1 |
| Supplemental: 25 μg | Supplemental: 250 μg | Supplemental: 2.5 mg | Supplemental: 1 mg (0.5–1 mg in the elderly) at 2–5 min intervals | Supplemental: usually not required Wait at least 10 min | Supplemental: usually not required Wait at least 10 min | Supplemental: 25% of initial dose | Supplemental: 1.6 mg·kg−1 | |
| Infusion: 25–100 μg·kg−1·min−1 | ||||||||
| Onset of action | 3–5 min | Immediate | 5–10 min | 30–60 s | 8–15 min | 1 min | 30–60 s | 6.5 min |
| Peak effect | 5 min | Immediate | 15–30 min | 5–10 min | 15–30 min | 2–3 min | 2 min | 12 min |
| Duration of action | 1–2 h | 1–2 h | 1–6 h | 30–120 min | 8 h | 1–3 h | 4–8 min | 17 min |
| Metabolism | Hepatic | Hepatic | Hepatic | Hepatic | Hepatic | Hepatic | Hepatic | Hepatic |
| Renal excretion | <5% | <1% | 90% | <1% | <1% | <1% | 70% | 70% |
| Elimination half-life | 3–4 h | 1–2 h | 2 h | 1.5–2.5 h | 11–22 h | 20–50 h | 3–12 h | 45 min |
| Major/common adverse evens | Respiratory depression, nausea and vomiting | See fentanyl | See fentanyl | Respiratory depression, hypotension | See midazolam | See midazolam | Respiratory depression, bradycardia, hypotension, pain at the injection site | Respiratory depression, hypotension, paraesthesiae, pruritus |
| Antagonists | Naloxone 100–200 μg (1.5-3 μg·kg−1) with supplemental doses of 100 μg every 2 min until reversal occurs | Flumazenil 0.2 mg, repeated every 60 s up to 1 mg; if a continuous infusion is required the dose is 0.1–0.4 mg·h−1 | No antagonist available | |||||
| Comments | Combination with benzodiazepines may enhance respiratory depression Administer prior to the benzodiazepines, as a lower dose of benzodiazepine will be required to achieve the desired degree of sedation | See fentanyl | See fentanyl | Combination with opiates may enhance respiratory depression | See midazolam | See midazolam | Combination with opiates may enhance respiratory depression Dose and rate of administration should be adjusted according to desired level of sedation and response For patients >65 years or with severe systemic disease reduce the dose by 25% | See propofol |
Adapted from [10, 18, 36].