Opioid · Analgesic

Hydromorphone (Dilaudid)

Also called Dilaudid

Reviewed by Alex G, BSN, RN, CEN, CCRN, CMC, NREMT-P · From the Reference tab of the app

Indications

Acute severe pain, IV, IM, SC or by PCA
Analgesia in ventilated ICU patients, by bolus or infusion
Alternative to morphine when histamine release or, with dose reduction, kidney impairment is a concern
Opioid-tolerant patients who need large doses (high-potency 10 mg/mL product)

Dosing

Infusion start: 0.5–1 mg/h (PADIS range 0.5–3 mg/h). Titration: 0.25–0.5 mg/h, with boluses every 15–30 minutes.

Where	Dose
Other common pushes	Hydromorphone: 0.2–0.5 mg IV every 5–15 min (about 7 times morphine)
Opioid equianalgesic doses	Hydromorphone: 1.5 mg IV = 7.5 mg PO
Other ICU drugs	Hydromorphone: Use lower doses; metabolite causes neuroexcitation

On the quick cards

Mechanism of action

Hydromorphone is a full μ-opioid agonist with little κ or δ activity, acting through the same Gi/o signaling as morphine: less cAMP, open GIRK potassium channels and closed presynaptic calcium channels in pain pathways. It binds the μ receptor more tightly than morphine (Ki under 1 nM, Volpe 2011), which helps explain its 5–7-fold potency by weight. Its main metabolite, H3G, has no analgesic action but excites neurons when it accumulates.

Pharmacology

CNS: analgesia and sedation like morphine with a faster peak; myoclonus, agitation, allodynia or seizures when H3G accumulates
Respiratory: dose-related depression, the main danger in potency mix-ups
Cardiovascular: less histamine release and hypotension than morphine, though both occur
GI and Other: constipation, nausea, itching, urinary retention

Pharmacokinetics

Onset	Within 5 min IV (Coda 1997)
Peak	10–20 min IV (Coda 1997)
Duration	About 2–4 h IV
Half-life	About 2.3 h IV (label)
Distribution	Vd about 300 L (about 4 L/kg, label)
Protein binding	8–19% (label)
Metabolism	Liver glucuronidation (UGT2B7) of over 95% of a dose to H3G; minor 6-hydroxy reduction products; no 6-glucuronide (label)
Elimination	Urine, mainly as H3G; about 7% unchanged
Organ failure	Exposure doubles in moderate and quadruples in severe kidney impairment and rises 4-fold in moderate liver impairment; start at one-quarter to one-half the usual dose (label)
Bioavailability	Oral low and variable (about 25–50%), so IV:PO is about 1:5

Chemistry

Semisynthetic phenanthrene from morphine: the 6-hydroxyl becomes a ketone and the 7,8 double bond is saturated (4,5α-epoxy-3-hydroxy-17-methylmorphinan-6-one)
Keeps morphine's natural (−) stereochemistry; pKa about 8.2, so mostly ionized at pH 7.4, and only modestly more lipid soluble than morphine
Hydrochloride 0.2–4 mg/mL in citrate buffer, pH 3.5–5.5, plus a high-potency 10 mg/mL for opioid-tolerant patients only; protect from light (label)

Adverse effects and cautions

In the one-pagers

End of Life, Hospice, Pain and SleepFentanyl patch safety: The transdermal system is only for opioid-tolerant clients: for a week or longer, at least 60 mg of oral morphine a day, 30 mg of oral oxycodone or 8 mg of oral hydromorphone, or an equivalent. It is contraindicated in opioid-naive clients and for acute, intermittent, postoperative or mild pain, because deaths have followed (FDA label, revised 12/2025).

Practice End of Life, Hospice, Pain and Sleep questions free27 exam-style questions with rationales on the topic where Hydromorphone comes up most. No account or download needed.

Practice free in your browser2,150+ exam-style questions with rationales. No account, no ads. Also free on the App Store and Google Play.

Sources

FDA label: Dilaudid Injection (2026)
FDA label: Hydromorphone HCl Injection, Fresenius Kabi (2026)
PubChem: hydromorphone
Coda 1997 (IV onset and potency)

For education and exam preparation only. Follow your institution’s protocols. Typical adult values for study. Follow the order, the label and your institution's protocols.