Hydrocodone
Norco / Vicodin (with acetaminophen)
Semisynthetic oral μ-opioid agonist
μ-opioid agonist, roughly equipotent to oral morphine; partly a prodrug converted to hydromorphone via CYP2D6.
Indications
- •Moderate postop pain (oral)
- •Multimodal oral analgesia
Dosing
| Context | Adult | Pediatric |
|---|---|---|
| Oral (usually with acetaminophen) | 5–10 mg PO q4–6h | — |
Pharmacokinetics
Onset 10–20 min PO, duration 4–6 h.
Respiratory effects
Dose-dependent depression.
Side effects
- !Constipation
- !Sedation
- !N/V
- !CYP2D6-dependent variability in efficacy
Contraindications
- ×Ileus / bowel obstruction
- ×MAOI within 14 days (relative)
Reversal / antidote
Naloxone
Clinical pearls
- ★Almost always combined with acetaminophen — respect the APAP maximum.
- ★CYP2D6 poor metabolizers get less analgesia; ultra-rapid metabolizers get more.
Other drugs in Narcotics & Analgesics
- Fentanyl
μ-opioid receptor agonist. ~100× potency of morphine.
- Remifentanil
μ-opioid agonist. Ester linkage hydrolyzed by nonspecific tissue + plasma esterases — no organ-dependent clearance.
- Morphine
μ-opioid receptor agonist. Active metabolite morphine-6-glucuronide (M6G) is analgesic and renally cleared — accumulates in renal failure → prolonged sedation/respiratory depression. Causes histamine release.
- Hydromorphone
μ-opioid agonist ~5–7× more potent than morphine. No clinically significant active metabolites → safer than morphine in renal failure. Less histamine release.
- Sufentanil
Most potent opioid in common clinical use — ~1000× morphine, ~10× fentanyl. High lipid solubility.
- Alfentanil
μ-opioid agonist ~1/5–1/10 the potency of fentanyl but FASTEST onset of the family — low pKa means a high non-ionized fraction at physiologic pH.
- Meperidine
μ-opioid agonist ~1/10 morphine, plus κ-agonism (anti-shivering). Active metabolite normeperidine is renally cleared, proconvulsant, and neurotoxic.
Suggested reading
- •Stoelting & Hines, Pharmacology & Physiology in Anesthetic Practice, 6e
- •Miller's Anesthesia, 9e
- •FDA package insert
