Table 2.

Opioid Potencies and Special Features^a

Drug	Parenteral (mg equivalent)	Oral	Duration (h)	Special Features
Morphine	10	30 mg	4	Morphine sulfate controlled release has 12-h duration
Codeine	120	200 mg	4	Ceiling effect as dose increases, low lipophilic
Oxycodone	4.5	30 mg	4	Oxycontin (10, 20, 40 mg slow release) every 12 h
Hydromorphone	2	8 mg	5	Suppository 12 mg = 10 mg parenteral morphine
Levorphanol	2	4 mg	4	Low nausea and vomiting, low lipophilic
Methadone	5	10 mg	2–12	Cumulative effect, day 3–5 decrease respiration, equianalgesic ratio varies considerably
Meperidine	100	300 mg	3	κ, proconvulsant metabolite, peristaltic slowing and sphincter of Oddi decrease
Fentanyl	0.1	25 μg sublingual	1 (patch 72 h)	50-μg patch = 30 mg/d morphine intramuscular/intravenous
Sufentanil	Not recommended	15 μg sublingual	1	High potency with low volume of fluid
Propoxyphene	Not available	325 mg	4	High dose leads to psychosis
Pentazocine	60	150 mg	3	δ, κ agonist-antagonist, nasal 1 mg every 1–2 h
Butorphanol	2	Not available, 3 mg (intramuscular), 2 mg (nasal)	Nasal 1 mg every1–2 h	μ, δ, κ agonist-antagonist
Buprenorphine	0.3	4 mg	4–6	Partial agonist
Tramadol	Not available	150 mg	4	μ agonist, decreased reuptake 5-hydroxytryptamine and norepinephrine P450 metabolism
Nalbuphine	10	Not available	3	Agonist-antagonist

^aAdapted with permission from Stern et al.³³