Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
CLOMID vs NALBUPHINE
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Competitive antagonist of estrogen receptors (ER) in hypothalamus and pituitary, leading to increased gonadotropin-releasing hormone (Gn RH) and subsequent LH and FSH release, stimulating ovulation.
Mixed opioid agonist-antagonist; agonist at κ-opioid receptors and antagonist/partial agonist at μ-opioid receptors.
Treatment of ovulatory dysfunction in women desiring pregnancy (FDA approved),Off-label: treatment of male infertility (oligospermia)
Moderate to severe pain,Supplement to balanced anesthesia,Preoperative and postoperative analgesia,Obstetrical analgesia during labor and delivery
50 mg orally once daily for 5 days, starting on day 5 of the menstrual cycle. May increase to 100 mg daily if no response.
10-20 mg IV/IM/SC every 3-6 hours as needed for pain; maximum single dose 20 mg, maximum total daily dose 160 mg.
Terminal half-life is 5–7 days for zuclomiphene (active isomer), with prolonged elimination due to enterohepatic recirculation.
Terminal elimination half-life is 5 hours; clinically, in hepatic impairment or elderly, half-life may be prolonged up to 8-10 hours.
Hepatic via CYP3A4 and CYP2D6; undergoes enterohepatic circulation; terminal half-life ~5-7 days
Hepatic metabolism primarily via glucuronidation and oxidative pathways; minor involvement of CYP450 enzymes.
Primarily hepatic metabolism; metabolites excreted in feces (42%) and urine (8% unchanged).
Primarily hepatic metabolism; <5% excreted unchanged in urine; about 70% excreted in feces via biliary elimination.
Highly protein bound (>99%), primarily to albumin.
Approximately 50% bound to plasma proteins, primarily albumin.
Not well-characterized; limited data suggest a large Vd (>100 L) due to extensive tissue distribution.
2.3 L/kg; indicates extensive tissue distribution, consistent with moderate lipophilicity.
Oral bioavailability is approximately 50% due to first-pass metabolism.
Intravenous: 100%; Intramuscular: approximately 80%; Oral: negligible (<20%) due to extensive first-pass metabolism.
No specific adjustment required; use caution in severe impairment (Cr Cl <30 m L/min) as data limited.
Cr Cl 30-50 m L/min: administer 75% of normal dose every 6 hours; Cr Cl <30 m L/min: administer 50% of normal dose every 8 hours.
Contraindicated in severe hepatic impairment (Child-Pugh class C). For mild to moderate impairment, no adjustment recommended, but monitor liver function.
Child-Pugh A: no adjustment; Child-Pugh B: reduce dose by 25%; Child-Pugh C: reduce dose by 50% or use alternative.
Not indicated for use in children; safety and efficacy not established.
0.1-0.2 mg/kg IV/IM/SC every 3-6 hours as needed; maximum single dose 20 mg.
Not indicated for postmenopausal women. Use not recommended in elderly due to lack of efficacy in anovulation.
Initiate at 50% of adult dose (5-10 mg) and titrate cautiously due to increased sensitivity and risk of respiratory depression.
None
Risk of respiratory depression, particularly in opioid-naive patients; risk of dependence and abuse; concomitant use with benzodiazepines or CNS depressants may cause profound sedation, respiratory depression, coma, and death.
Ovarian hyperstimulation syndrome (OHSS),Ovarian enlargement,Visual disturbances (especially with prolonged use),Multiple pregnancy (increased risk),Ectopic pregnancy,Ovarian cancer risk (theoretical, based on prolonged use)
Respiratory depression may occur, especially in elderly, cachectic, or debilitated patients,Avoid use in patients with head injury or increased intracranial pressure,May precipitate withdrawal in opioid-dependent patients,Hypotension, biliary tract spasm, and seizure risk
Pregnancy (Category X),Liver disease or dysfunction,Undiagnosed abnormal vaginal bleeding,Ovarian cyst or enlargement not due to polycystic ovary syndrome,Hypersensitivity to clomiphene or components
Hypersensitivity to nalbuphine or any component,Significant respiratory depression,Acute or severe bronchial asthma in an unmonitored setting,Suspected or known gastrointestinal obstruction
No specific food interactions. Avoid grapefruit as it may alter metabolism (theoretical due to CYP3A4 involvement).
No significant food-drug interactions. Avoid alcohol and grapefruit juice as they may enhance CNS depression.
Clomiphene citrate is contraindicated in pregnancy. It is associated with an increased risk of fetal malformations, including neural tube defects, specifically when exposure occurs during the first trimester. Second and third trimester risks are not well studied due to contraindication, but theoretical risks include ovarian hyperstimulation syndrome (OHSS) effects on pregnancy.
FDA Category C. First trimester: Limited human data, no evidence of major malformations in animal studies at 4-6x MRHD. Second/third trimester: Chronic use may cause neonatal opioid withdrawal syndrome (NOWS) including irritability, hypertonia, tremors, poor feeding. Use only if benefit outweighs risk.
Safety in breastfeeding is not established. Clomiphene may reduce milk production. The M/P ratio is unknown. It is generally not recommended during breastfeeding.
Excreted in human milk in low concentrations (M/P ratio ~0.6). Relative infant dose estimated 0.5-1% of maternal weight-adjusted dose. Monitor infant for sedation and poor feeding. American Academy of Pediatrics considers compatible with breastfeeding with caution.
No dose adjustments are relevant as clomiphene is contraindicated in pregnancy. Pharmacokinetic changes in pregnancy are not applicable due to contraindication.
No specific dose adjustments recommended for pregnancy. Increased clearance and volume of distribution in third trimester may potentially reduce efficacy; titrate to effect. Avoid in prolonged labor due to risk of fetal bradycardia.
Monitor ovarian size via ultrasound to reduce risk of ovarian hyperstimulation syndrome (OHSS). Limit course to 3-6 cycles due to increased risk of ovarian tumors. Check pregnancy test before each cycle. Use with caution in liver disease.
Nalbuphine is a mixed agonist-antagonist opioid with a ceiling effect for respiratory depression, making it safer than pure agonists. It can precipitate withdrawal in opioid-dependent patients. Monitor for sedation and hypotension. Reversal with naloxone may be less effective. Use with caution in hepatic impairment. Not recommended for chronic pain due to psychotomimetic effects.
Take exactly as prescribed, typically 50 mg daily for 5 days starting on day 5 of menstrual cycle.,Report abdominal pain, bloating, nausea, or weight gain (possible OHSS).,Avoid alcohol due to hepatotoxicity risk.,Most pregnancies occur within first 3 cycles; consider alternative after 6 cycles.,May cause visual disturbances; report blurred vision or spots.
Take exactly as prescribed; do not increase dose or frequency without consulting your doctor.,Avoid alcohol and other central nervous system depressants (e.g., benzodiazepines, sleep aids) as they can increase dizziness and drowsiness.,Do not drive or operate heavy machinery until you know how nalbuphine affects you.,Report any signs of withdrawal (e.g., restlessness, tearing, runny nose, yawning, sweating) if you have been taking other opioids.,Seek emergency care if you experience trouble breathing, severe dizziness, or hallucinations.,Do not stop abruptly; tapering may be needed to avoid withdrawal symptoms.
No interactions on record
"The combination of trifluoperazine, a phenothiazine antipsychotic, with nalbuphine, a mixed opioid agonist-antagonist, can lead to additive central nervous system (CNS) depression, including increased sedation, respiratory depression, and hypotension. Trifluoperazine may enhance the depressant effects of nalbuphine on the brainstem respiratory centers and vasomotor centers. Clinically, this interaction may result in excessive sedation, respiratory compromise, and orthostatic hypotension, particularly in elderly or debilitated patients."
"Combined use of nalbuphine, a mixed opioid agonist-antagonist, with entacapone, a catechol-O-methyltransferase (COMT) inhibitor, may increase the risk of opioid-related adverse effects, including respiratory depression and sedation, due to additive central nervous system depression. Entacapone can also inhibit the metabolism of catecholamines, potentially exacerbating opioid-induced constipation and urinary retention. Clinically, patients may experience enhanced sedation or respiratory compromise, particularly in elderly or debilitated populations."
"Concomitant use of clozapine and nalbuphine may potentiate central nervous system (CNS) depression, leading to additive sedative and respiratory depressant effects. Both drugs act on the CNS via distinct mechanisms but converge on common pathways, increasing the risk of hypotension, bradycardia, and profound sedation. Clinically, patients may experience excessive drowsiness, confusion, or respiratory compromise, particularly in those with pre-existing comorbidities or concurrent use of other CNS depressants."
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about CLOMID vs NALBUPHINE, answered by our medical review team.
CLOMID is a Selective Estrogen Receptor Modulator that works by Competitive antagonist of estrogen receptors (ER) in hypothalamus and pituitary, leading to increased gonadotropin-releasing hormone (Gn RH) and subsequent LH and FSH release, stimulating ovulation.. NALBUPHINE is a Opioid Agonist-Antagonist that works by Mixed opioid agonist-antagonist; agonist at κ-opioid receptors and antagonist/partial agonist at μ-opioid receptors.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between CLOMID and NALBUPHINE 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 CLOMID is: 50 mg orally once daily for 5 days, starting on day 5 of the menstrual cycle. May increase to 100 mg daily if no response.. The standard adult dose of NALBUPHINE is: 10-20 mg IV/IM/SC every 3-6 hours as needed for pain; maximum single dose 20 mg, maximum total daily dose 160 mg.. 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 CLOMID and NALBUPHINE 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. CLOMID is classified as Category C. Clomiphene citrate is contraindicated in pregnancy. It is associated with an increased risk of fetal malformations, including neural tube defects, specifically when exposure occurs. NALBUPHINE is classified as Category A/B. FDA Category C. First trimester: Limited human data, no evidence of major malformations in animal studies at 4-6x MRHD. Second/third trimester: Chronic use may cause neonatal opioi. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.