Table 4.

Dose Administration Data for Commonly Used Opioid Analgesics

DrugApproximate Equianalgesic Oral DoseApproximate Equianalgesic Parenteral DoseRecommended Starting Dose (Adults >50 kg Body Weight)
Morphine20–60 mg/day initial starting dose; then 30 mg q3-h (IR)10 mg q3–4 hours30 mg q3–4 hours*10 mg q3–4 hours (use of IV route is preferable)
Oxycodone30 mg q3–4 hours (IR)NA10 mg q3–4 hoursNA
Hydromorphone7.5 mg q3–4 hours1.5 mg q3–4 hours6 mg q3–4 hours1.5 mg q3–4 hours
Methadone5–10 mg q6–8 hours5–10 mg q6–8 hours5–10 mg q6–8 hours2.5–5 mg q6–8 hours
  • IR, immediate release; IV, intravenous; NA, not available.

  • * Starting dose of 20 to 60 mg/day may be used to avoid adverse effects such as vomiting.

  • Transdermal fentanyl 100 μg/hr is approximately equivalent to 2 to 4 mg/hr of IV morphine. A conversion factor for transdermal fentanyl that can be used for equianalgesic calculation is 17 μg/hr. Roughly, the dose of transdermal fentanyl in μg/hr is approximately one-half of the 24-hour dose of oral morphine.

  • For morphine and hydromorphone, rectal administration is an alternate route for patients unable to take oral medication, but equianalgesic doses may differ from oral and parenteral doses because of pharmacokinetic differences.

  • Reprinted with permission from Nicholson.8