| Drug (United States brand name) | Approximate equianalgesic doses* | Sample initial dose for opioid-naïve adult¶ | Serum half-life (in hours) | Duration of analgesic effect (in hours) | Comments |
| Parenteral opioids |
| Fentanyl (Sublimaze) | 100 mcg IV | 25 to 50 mcg for moderate pain or 50 to 100 mcg for more severe pain IV/subcutaneous; repeat every two to five minutes as needed until adequate pain relief | 7 to 12 | 0.5 to 1 (IV)
1 to 2 (subcutaneous) | - Fentanyl does not release histamine and may therefore be preferred in the presence of hemodynamic instability or bronchospasm.
- Potential for drug interactions as it is hepatically metabolized by CYP3A4.Δ
- Duration of effect increases after repeated use.
- May be used for PCA, less commonly than hydromorphone and morphine.
|
| Hydromorphone (Dilaudid) | 1.5 mg IV | 0.2 to 0.5 mg IV; repeat every five minutes as needed until adequate pain relief, then 0.2 to 0.5 mg IV every three to four hours as needed | 2 to 3 | 3 to 4 | - Lower potential for drug interactions as it is hepatically metabolized primarily by glucuronidation.
- Use reduced dose in renal and/or hepatic impairment.
- May be used for PCA.
|
| Morphine (Infumorph, others) | 10 mg IV | 1 to 3 mg IV; repeat every five minutes as needed until adequate pain relief; then 1 to 3 mg IV every three to four hours as needed | 2 to 3 | 4 to 5 | - Lower potential for drug interactions as it is hepatically metabolized primarily by glucuronidation.
- In patients with renal impairment, clearance of active metabolites that contribute to hyperalgesia and neuroexcitation is decreased; hydromorphone or fentanyl may be preferred.
- Histamine release and vagally mediated venodilation, hypotension, and bradycardia can be significant.
- May be used for PCA.
- Subcutaneous not recommended due to local tissue irritation.
|
| Oral immediate-release opioids |
| Codeine | 200 mg orally | 15 to 60 mg orally every four to six hours as needed | 2 to 4 | 4 to 6 | - Potential for drug interactions as it is hepatically metabolized by CYP2D6 to active metabolite (ie, morphine).
- Analgesic and adverse effects are unpredictable because rate of conversion to morphine is genetically determined by polymorphic CYP2D6 enzyme. Generally not recommended for this reason.
- Oral immediate-release preparations are also available in combinations with acetaminophen (eg, Tylenol #3); acetaminophen component dose limits apply to combinations.
|
| Hydrocodone (immediate-release only available in US in combination products, eg, Vicodin, Lorcet, others) | 30 mg orally | 5 to 10 mg orally every six hours as needed | 3 to 4 | 4 to 8 | - Hepatically metabolized by CYP2D6 and 3A4 to active (ie, hydromorphone) and inactive metabolites.
- Oral immediate-release preparations are only available in United States in combinations with acetaminophen or ibuprofen; nonopioid component dose limits apply.
|
| Hydromorphone (Dilaudid) | 7.5 mg orally | 2 to 4 mg orally every four hours as needed | 2 to 3 | 3 to 6 | - Refer to comments for parenteral hydromorphone above.
|
| Morphine | 30 mg orally | 15 to 30 mg orally every four hours as needed | 2 to 3 | 3 to 6 | - Refer to comments for parenteral morphine above.
|
| Oxycodone (Oxy-IR, Roxicodone, others) | 20 mg orally | 5 to 10 mg orally every four to six hours as needed | 2 to 3 | 3 to 6 | - Hepatically metabolized by CYP2D6 and 3A4 to active and inactive metabolites.
- Oral immediate-release preparations are also available in combinations with acetaminophen, aspirin, or ibuprofen; nonopioid component dose limits apply to combinations.
|
| Oxymorphone (Opana) | 10 to 15 mg orally | 5 to 10 mg orally every four to six hours as needed | 7 to 9 | 3 to 6 | |
| Tramadol (Ultram, others) | Not established | 50 to 100 mg every four to six hours as needed | 6 to 9 (includes active metabolite) | 4 to 6 | - Multiple mechanisms of action: Weak mu-opioid agonist and reuptake inhibitor of norepinephrine and serotonin.
- Risk of drug interactions.
- Use reduced dose for moderate renal or hepatic impairment.
- Not recommended in severe organ impairment or if risk for seizures.
- Effects not fully reversed by naloxone.
- Also available in combinations with acetaminophen; dose limits apply.
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