NEBUPENT
Clinical safety rating: caution
Comprehensive clinical and safety monograph for NEBUPENT (NEBUPENT).
Nebupent (pentamidine isethionate) is an antimicrobial agent that inhibits the synthesis of DNA, RNA, phospholipids, and proteins in protozoa. Its mechanism may involve interference with polyamine synthesis and inhibition of dihydrofolate reductase.
| Metabolism | Not extensively metabolized; primarily eliminated unchanged by the kidneys. Minor hepatic metabolism via unknown pathways. |
| Excretion | Renal: approximately 90% as unchanged drug; biliary/fecal: minimal (<5%) |
| Half-life | Terminal elimination half-life: 6-9 hours (prolonged in renal impairment; clinical context: supports once-daily dosing for treatment, but prophylaxis may require reduced frequency in renal dysfunction) |
| Protein binding | Approximately 99% bound, primarily to albumin and lipoproteins |
| Volume of Distribution | Vd: 0.3-0.5 L/kg; clinical meaning: limited extravascular distribution, predominantly remains in plasma and interstitial space |
| Bioavailability | Inhalation: variable, approximately 10-20% systemic absorption; IV: 100% |
| Onset of Action | Intravenous: within 1-2 hours (time to therapeutic concentrations following infusion); Inhalation: effects on pulmonary protozoa may take days to weeks |
| Duration of Action | Duration depends on dose and route; IV dosing provides 24-hour coverage for prophylaxis; inhalation effects persist approximately 1 week between doses in prophylaxis |
300 mg via inhalation once every 4 weeks for prophylaxis of Pneumocystis jirovecii pneumonia.
| Dosage form | FOR SOLUTION |
| Renal impairment | No dosage adjustment required for renal impairment. Not significantly excreted renally. |
| Liver impairment | No specific guidelines; use caution in severe hepatic impairment due to limited data. |
| Pediatric use | 5 years and older: 300 mg via inhalation once every 4 weeks. Safety and efficacy not established under 5 years. |
| Geriatric use | No specific dose adjustment recommended; monitor for adverse effects and renal function due to age-related decline. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for NEBUPENT (NEBUPENT).
| Breastfeeding | Excretion into human breast milk unknown; however, because pentamidine isethionate is poorly absorbed orally, systemic exposure to the infant is likely minimal. Caution should be exercised; consider discontinuing nursing or drug based on importance to mother. M/P ratio: not available. |
| Teratogenic Risk | FDA Pregnancy Category C. Animal studies have shown teratogenic effects (skeletal anomalies, embryotoxicity) at doses less than or equal to the human dose. No adequate human studies in pregnant women. First trimester: potential risk of teratogenicity based on animal data; should only be used if potential benefit justifies risk. Second/third trimesters: limited data; fetal/neonatal adverse effects cannot be ruled out; use only if clearly needed. |
■ FDA Black Box Warning
Respiratory depression, arrhythmias, hypotension, and hypoglycemia may occur. Use with caution in patients with renal impairment, hepatic impairment, or pre-existing cardiac conduction abnormalities.
| Serious Effects |
Hypersensitivity to pentamidine or any component of the formulation
| Precautions | Severe hypotension, hypoglycemia, cardiac arrhythmias (including torsade de pointes), acute pancreatitis, nephrotoxicity, leukopenia, thrombocytopenia, and Stevens-Johnson syndrome. Monitor renal function, liver enzymes, blood glucose, and ECG during therapy. |
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| Fetal Monitoring | Monitor maternal renal function (serum creatinine, BUN), hepatic function (LFTs), and blood glucose (risk of hypoglycemia). Fetal monitoring: ultrasound for growth and anatomy if used in pregnancy. Neonatal monitoring for hypoglycemia and electrolyte disturbances if used near delivery. |
| Fertility Effects | Animal studies have shown reduced fertility in male rats at high doses; relevance to humans unknown. Effects on female fertility not reported. Oligospermia and testicular atrophy observed in animal studies. |