Dilaudid
Dilaudid
Generic Name
Dilaudid
Mechanism
- Selective μ‑opioid receptor agonist: Binds preferentially to μ receptors in the CNS and peripheral nervous system, mimicking endogenous endorphins.
- Analgesic cascade: Activation inhibits ascending pain pathways and reduces the release of excitatory neurotransmitters.
- Rapid onset: Shorter alkyl chain and higher lipophilicity give quicker CNS penetration, facilitating earlier pain control.
Pharmacokinetics
| Parameter | Details |
| Absorption | Oral: ~70–90 % bioavailability; IV: 100%. Rapid peak plasma levels within 15 min (IV), 1–2 h (oral). |
| Distribution | Widely distributed (Vd ≈ 0.5–0.75 L/kg). Crosses the blood–brain barrier and the placenta. |
| Metabolism | Primarily hepatic via glucuronidation (UGT2B7) to inactive 3‑glucuronide; minimal cytochrome P450 interaction. |
| Elimination | Renal excretion of metabolites (≈ 70 %); half‑life 3–4 h (IV), 4–5 h (oral) in adults with normal kidney function. |
| Adjustments | Dose reductions needed in severe hepatic impairment; dose adjustment not required for mild‑moderate renal impairment but monitor for accumulation. |
Indications
- Acute and chronic severe pain (post‑surgical, traumatic, oncologic).
- Management of breakthrough cancer pain.
- Adjunctive analgesia during palliative or end‑of‑life care.
- Short‑term analgesia for severe inflammatory conditions.
Contraindications
| Category | Key Points |
| Absolute Contraindications | Known hypersensitivity to hydromorphone or other opioids; active respiratory depression; concurrent use of monoamine oxidase inhibitors. |
| Relative Contraindications | Severe hepatic or renal dysfunction, pregnancy (category C), lactation, and patients with uncontrolled seizures. |
| Warnings | Respiratory depression, tolerance/withdrawal, opioid-induced constipation, pruritus, nausea/vomiting, and potential for abuse. |
| Drug Interactions | Potentiation of CNS depression with benzodiazepines, alcohol, or other opioids; risk of QT prolongation with certain anti‑arrhythmics. |
Dosing
- Adult IV: 1–2 mg every 3–4 h as needed; titrate based on pain score and clinical response.
- Adult Oral: 2–4 mg every 4–6 h; may be increased to a maximum of 20 mg/day in chronic pain.
- ICU/Intensive: Continuous infusion 10–30 μg/h; titrate to ≥95 % analgesia.
- Pediatric: 0.02–0.05 mg/kg IV every 4–6 h; adjust for weight and renal function.
- Elderly: Start at lower end of dose range; monitor for sedation and respiratory depression.
Administration Tips
• Use an opioid wheel to guide incremental titration.
• For breakthrough pain, use a rapid‑acting form (IV/SC) if oral absorption is impaired.
• Rotate with other analgesics to reduce tolerance.
Adverse Effects
Common
• Pruritus, nausea, vomiting, constipation, dizziness, urinary retention, somnolence.
Serious
• Respiratory depression (bradypnea, apnea).
• Cardiac arrhythmias, especially QT prolongation.
• Opioid-induced hyperalgesia with chronic use.
• Withdrawal symptoms (if abruptly discontinued).
Monitoring
| Parameter | Frequency | Rationale |
| Respiratory rate & O₂ sat | Every 15–30 min (IV) or as clinically indicated | Detect early depression. |
| Pain/response assessment | Every 4 h | Guide dose adjustments. |
| Vital signs (HR, BP) | Every 4–6 h | Monitor hypotension or bradycardia. |
| Kidney/ liver function tests | Baseline, then monthly | Adjust dosing in dysfunction. |
| Serum drug level | Only in special circumstances | For therapeutic drug monitoring. |
| Signs of opioid withdrawal | Continuous | Prevent abrupt cessation. |
Clinical Pearls
- Rapid‑acting formulations (IV/SC) are paramount for breakthrough pain; avoid using oral in patients with nausea or vomiting.
- Hydromorphone vs Morphine: Lower dose equivalency (1 mg hydromorphone ≈ 4–5 mg morphine) reduces the risk of over‑medication and enables finer titration.
- Naloxone co‑administration: Use short‑acting naloxone with IV hydromorphone to counteract hypotension or bradypnea when indicated.
- Opioid rotation: Switching to hydromorphone can break the cycle of increasing doses of other opioids, decreasing tolerance development.
- Kidney‑compromised patients: Monitor for accumulation of glucuronide metabolites; consider a reduction of 25–50 % of the maintenance dose.
- Elderly management: Consider starting at 0.5–1 mg every 4–6 h due to decreased clearance and increased sensitivity to CNS effects.
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• *This drug card summarizes the critical pharmacology of Dilaudid for rapid reference by medical students, residents, and practicing clinicians.*