Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
DILAUDID-HP vs FLUIDIL
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Hydromorphone is a full mu-opioid receptor agonist with high affinity for mu-opioid receptors, producing analgesia, euphoria, and sedation. It also binds to kappa and delta opioid receptors with lower affinity.
Fluidil is a thiazide-like diuretic that inhibits the sodium-chloride symporter (NCC) in the distal convoluted tubule of the nephron, reducing sodium and chloride reabsorption and promoting diuresis.
Management of pain severe enough to require an opioid analgesic and for which alternative treatments are inadequate (FDA-approved),Off-label: Treatment of acute pain, postoperative pain, cancer pain, and breakthrough pain
Hypertension,Edema associated with congestive heart failure,Edema associated with renal disease,Edema associated with hepatic cirrhosis
Initial dose: 0.2-0.6 mg IV/IM/SC every 2-4 hours as needed; usual adult dose: 0.2-0.4 mg IV/IM/SC. Oral: 1-2 mg every 3-6 hours. Dose titration based on pain severity.
5 mg orally once daily.
Terminal elimination half-life: 2.3–4 hours. In clinical context, consistent with dosing interval of 4–6 hours for immediate-release formulations; prolonged in hepatic or renal impairment.
Terminal elimination half-life: 1.5-2 hours (prolonged in hepatic impairment to 4-6 hours).
Hydromorphone is extensively metabolized in the liver via glucuronidation to hydromorphone-3-glucuronide (major metabolite) and to a lesser extent via reduction to dihydroisomorphine and dihydromorphine. Minor CYP2C9 and CYP3A4 involvement.
Fluidil is extensively metabolized in the liver, primarily via glucuronidation and sulfation; cytochrome P450 enzymes play a minor role.
Renal: predominantly as hydromorphone-3-glucuronide (H3G), unchanged hydromorphone (<6%), and other metabolites. Biliary/fecal: minimal.
Renal: 60-70% unchanged; biliary/fecal: <5%; hepatic metabolism: 25-35%.
Approximately 20–30%, primarily to albumin.
85-92% bound to albumin, alpha-1-acid glycoprotein.
1.2–1.8 L/kg. Indicates extensive tissue distribution, consistent with a lipophilic opioid.
0.8-1.2 L/kg (extensive tissue distribution).
Oral: 24–51% (first-pass metabolism); Intramuscular: 96% (relative to IV).
Oral: 60-80% (first-pass metabolism).
GFR 30-60 m L/min: reduce dose by 25-50%; GFR 10-29 m L/min: administer 50-75% of normal dose every 6-8 hours; GFR <10 m L/min: administer 25-50% of normal dose every 8-12 hours.
No dose adjustment required for GFR ≥30 m L/min. Not recommended for GFR <30 m L/min.
Child-Pugh Class A: no adjustment; Child-Pugh Class B: reduce initial dose by 50%; Child-Pugh Class C: avoid use or reduce dose by 75% with extended dosing interval.
Child-Pugh Class A: no adjustment. Child-Pugh Class B: 2.5 mg once daily. Child-Pugh Class C: not recommended.
Children >2 years: 0.1-0.2 mg/kg IV/IM/SC every 4-6 hours; maximum single dose 2 mg. Neonates/infants: 0.03-0.05 mg/kg IV/IM/SC every 4-6 hours.
Not established for pediatric patients <18 years.
Initial dose: 0.1-0.2 mg IV/IM/SC every 4-6 hours; reduce dose by 50% compared to younger adults; titrate cautiously due to increased sensitivity and risk of respiratory depression.
No specific adjustment; use caution due to increased sensitivity.
WARNING: ADDICTION, ABUSE, AND MISUSE; LIFE-THREATENING RESPIRATORY DEPRESSION; ACCIDENTAL INGESTION; NEONATAL OPIOID WITHDRAWAL SYNDROME; RISKS FROM CONCOMITANT USE WITH BENZODIAZEPINES OR OTHER CNS DEPRESSANTS; and RISKS OF USE IN PATIENTS WITH HEAD INJURY OR INCREASED INTRACRANIAL PRESSURE.
No FDA black box warning has been issued for Fluidil.
Addiction, abuse, and misuse,Life-threatening respiratory depression,Accidental ingestion,Neonatal opioid withdrawal syndrome,Risks from concomitant use with benzodiazepines or other CNS depressants,Adrenal insufficiency,Severe hypotension,Gastrointestinal effects (constipation, ileus),Seizures,Withdrawal
Electrolyte imbalance (hypokalemia, hyponatremia, hypomagnesemia),Hypovolemia and hypotension,Hyperuricemia and gout,Azotemia and renal impairment,Sulfonamide allergy cross-reactivity
Significant respiratory depression,Acute or severe bronchial asthma in an unmonitored setting or in absence of resuscitative equipment,Known or suspected gastrointestinal obstruction, including paralytic ileus,Hypersensitivity to hydromorphone or any component of the product
Anuria,Hypersensitivity to Fluidil or other sulfonamide-derived drugs,Hepatic coma or pre-coma,Severe electrolyte depletion
Avoid alcohol while taking DILAUDID-HP, as it can potentiate CNS depression and increase the risk of respiratory depression. Grapefruit juice may inhibit CYP2D6 and CYP3A4 metabolism, potentially increasing hydromorphone levels; avoid concurrent consumption. High-fat meals may delay absorption; maintain consistent timing with or without food.
Avoid high-potassium foods (e.g., bananas, oranges, avocados, spinach, potatoes, salt substitutes with potassium chloride). Limit alcohol intake as it may worsen dizziness and dehydration. Grapefruit juice has not been reported to interact significantly, but caution is advised with other drugs. Maintain adequate fluid intake to prevent dehydration.
FDA Pregnancy Category C. First trimester: No well-controlled human studies; animal studies have shown teratogenicity at high doses. Second and third trimesters: Chronic maternal use may lead to neonatal opioid withdrawal syndrome (NOWS) and respiratory depression at birth. Avoid use during labor due to risk of neonatal respiratory depression.
FLUIDIL is contraindicated in pregnancy. First trimester: Associated with increased risk of major malformations, including neural tube defects and cardiac anomalies. Second and third trimesters: May cause oligohydramnios due to diminished fetal renal function; use may lead to fetal renal impairment, persistent ductus arteriosus, and craniofacial abnormalities.
Hydromorphone is excreted into breast milk. The milk-to-plasma (M/P) ratio is approximately 2.6. Limited data suggest low levels, but use caution due to potential for infant sedation and respiratory depression. The American Academy of Pediatrics considers hydromorphone compatible with breastfeeding if used short-term at low doses.
Excreted in human milk; M/P ratio not established. Use is not recommended during breastfeeding due to potential for serious adverse reactions in nursing infants.
Pregnancy does not significantly alter hydromorphone pharmacokinetics, but dose adjustments may be needed due to increased pain or opioid tolerance. Use lowest effective dose for shortest duration. Monitor for respiratory depression and adjust accordingly.
FLUIDIL is not indicated for use in pregnancy. No dosage adjustment recommendations are available for pregnant women; avoidance is mandatory.
DILAUDID-HP (high-potency hydromorphone) is indicated for opioid-tolerant patients only; 1 mg DILAUDID-HP is equivalent to 4 mg standard hydromorphone. Use with extreme caution in patients with respiratory compromise, COPD, or cor pulmonale. Avoid in patients with paralytic ileus or suspected GI obstruction. Monitor for serotonin syndrome when co-administered with serotonergic drugs. For PCA use, ensure proper programming to prevent overdose. Naloxone is the reversal agent; may require higher doses due to high potency.
Fluidil (a diuretic combination, e.g., hydrochlorothiazide and triamterene) may cause electrolyte disturbances; monitor potassium levels closely due to triamterene's potassium-sparing effect. Avoid use in patients with severe renal impairment (Cr Cl <30 m L/min) or hyperkalemia. Onset of diuresis occurs within 2 hours, peak effect at 4-6 hours. Administer in the morning to prevent nocturia.
This is a high-potency opioid; take exactly as prescribed and never increase dose without consulting your doctor.,Do not break, crush, or chew tablets; swallow whole to avoid rapid release of the drug.,Avoid alcohol and other central nervous system depressants (e.g., benzodiazepines, sedatives) as they can increase the risk of severe drowsiness, respiratory depression, and death.,Do not stop taking abruptly; withdrawal symptoms may occur. Consult your doctor for a tapering plan.,Constipation is a common side effect; maintain adequate fluid intake, fiber, and consider stool softeners or laxatives as needed.,Store securely out of reach of children and pets; properly dispose of unused medication at a take-back location.,Seek emergency medical attention if you experience difficulty breathing, extreme drowsiness, confusion, or fainting.,This medication may impair your ability to drive or operate machinery; avoid such activities until you know how it affects you.
Take this medication in the morning to reduce nighttime urination.,Avoid potassium supplements or high-potassium foods (e.g., bananas, oranges, salt substitutes) unless directed by your doctor.,Monitor for signs of electrolyte imbalance: muscle cramps, weakness, irregular heartbeat, or excessive thirst.,Stay hydrated but avoid excessive fluid intake; drink water as needed.,Report any rash, difficulty breathing, or swelling of the face/lips immediately.,Do not drive or operate machinery if you feel dizzy or lightheaded, especially during the first few days of treatment.
No interactions on record
No interactions on record
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about DILAUDID-HP vs FLUIDIL, answered by our medical review team.
DILAUDID-HP is a Opioid Analgesic that works by Hydromorphone is a full mu-opioid receptor agonist with high affinity for mu-opioid receptors, producing analgesia, euphoria, and sedation. It also binds to kappa and delta opioid receptors with lower affinity.. FLUIDIL is a Mineralocorticoid that works by Fluidil is a thiazide-like diuretic that inhibits the sodium-chloride symporter (NCC) in the distal convoluted tubule of the nephron, reducing sodium and chloride reabsorption and promoting diuresis.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between DILAUDID-HP and FLUIDIL depend on the specific clinical indication. These are agents from distinct pharmacological classes and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of DILAUDID-HP is: Initial dose: 0.2-0.6 mg IV/IM/SC every 2-4 hours as needed; usual adult dose: 0.2-0.4 mg IV/IM/SC. Oral: 1-2 mg every 3-6 hours. Dose titration based on pain severity.. The standard adult dose of FLUIDIL is: 5 mg orally once daily.. Dosing should always be individualized based on indication, renal and hepatic function, age, and other patient factors.
No direct drug-drug interaction has been formally documented between DILAUDID-HP and FLUIDIL in current clinical databases. However, individual patient risk factors including other medications, organ function, and comorbidities should always be evaluated by a qualified healthcare provider.
The maternal-fetal safety profiles differ. DILAUDID-HP is classified as Category C. FDA Pregnancy Category C. First trimester: No well-controlled human studies; animal studies have shown teratogenicity at high doses. Second and third trimesters: Chronic maternal u. FLUIDIL is classified as Category C. FLUIDIL is contraindicated in pregnancy. First trimester: Associated with increased risk of major malformations, including neural tube defects and cardiac anomalies. Second and thi. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.