PAROMOMYCIN SULFATE
Clinical safety rating: safe
Animal studies have demonstrated safety
Paromomycin is an aminoglycoside antibiotic that binds to the 30S ribosomal subunit, causing misreading of mRNA and inhibition of protein synthesis in susceptible bacteria. It also has direct amebicidal activity against Entamoeba histolytica by inhibiting protein synthesis.
| Metabolism | Paromomycin is minimally absorbed after oral administration; systemic absorption is negligible. It is not metabolized and is excreted unchanged in feces. |
| Excretion | Primarily renal excretion of unchanged drug via glomerular filtration; >90% of absorbed dose excreted in urine within 24 hours; negligible biliary/fecal elimination. |
| Half-life | Terminal elimination half-life: 2–3 hours in normal renal function; extends to 24–48 hours or longer in severe renal impairment, necessitating dose adjustment. |
| Protein binding | Negligible (<5%); does not bind significantly to plasma proteins. |
| Volume of Distribution | Vd: 0.25–0.4 L/kg; indicates distribution primarily in extracellular fluid, with poor penetration into cells and CNS. |
| Bioavailability | Oral: <3% (minimal absorption); topical: negligible systemic absorption; intramuscular: not clinically used. |
| Onset of Action | Oral: minimal systemic absorption; local onset in gut within 24 hours for amebiasis. Topical: not applicable. |
| Duration of Action | Duration of systemic effect: 6–8 hours after dose; clinical duration in hepatic coma/amebiasis depends on course length (5–10 days). |
25-35 mg/kg/day orally in 3 divided doses for 5-10 days for intestinal amebiasis; 1 g orally every 8 hours for 7 days for cryptosporidiosis.
| Dosage form | CAPSULE |
| Renal impairment | CrCl 30-50 mL/min: administer q12-18h; CrCl 10-29 mL/min: administer q24h; CrCl <10 mL/min: administer q48-72h. |
| Liver impairment | Child-Pugh A: no adjustment; Child-Pugh B: use with caution, monitor aminoglycoside levels; Child-Pugh C: contraindicated due to risk of nephrotoxicity and ototoxicity. |
| Pediatric use | 25-50 mg/kg/day orally in 3-4 divided doses; maximum 1.5 g/day. |
| Geriatric use | Reduce dose based on renal function; monitor serum creatinine and aminoglycoside levels; avoid prolonged use. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Other nephrotoxic or ototoxic drugs increase risk of toxicity Used for intestinal amebiasis not systemic infections.
| Breastfeeding | Paromomycin is poorly absorbed from the gastrointestinal tract, so systemic levels are very low. It is not known if paromomycin is excreted in human milk. The manufacturer recommends caution during breastfeeding. Due to the minimal systemic absorption, the risk to the nursing infant is likely low. The M/P ratio is not available. |
| Teratogenic Risk | Paromomycin sulfate is an aminoglycoside antibiotic with minimal systemic absorption after oral administration (less than 1%). Animal reproduction studies have not been conducted. There are no adequate and well-controlled studies in pregnant women. Due to negligible systemic absorption, the risk of teratogenicity is considered low. Use during pregnancy is generally avoided unless clearly needed, especially in the first trimester. There is a potential for ototoxicity and nephrotoxicity if systemic absorption occurs, but this is unlikely with oral dosing. |
■ FDA Black Box Warning
No FDA black box warnings.
| Common Effects | Diarrhea |
| Serious Effects |
["Hypersensitivity to paromomycin or any aminoglycoside antibiotic.","Intestinal obstruction (use in hepatic coma adjunct is contraindicated if obstruction present).","Ulcerative bowel lesions (risk of systemic absorption and toxicity)."]
| Precautions | ["Ototoxicity and nephrotoxicity: rare with oral use due to minimal absorption, but risk increases in patients with renal impairment or prolonged therapy.","Neuromuscular blockade: use caution in patients with myasthenia gravis or other neuromuscular disorders.","Superinfection: prolonged use may result in overgrowth of nonsusceptible organisms.","Pregnancy: only if clearly needed; crosses the placenta minimally.","Renal impairment: may increase risk of toxicity; monitor renal function."] |
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| Fetal Monitoring | No specific maternal or fetal monitoring is typically required due to the low systemic absorption. However, in cases of prolonged therapy or if there is any concern for systemic toxicity (e.g., in patients with gastrointestinal ulcerations), renal function (creatinine) and hearing (auditory function) should be monitored. For the fetus, standard prenatal care is sufficient. |
| Fertility Effects | There are no known adverse effects on fertility in humans. No animal fertility studies have been reported. Given the poor systemic absorption, significant effects on reproductive function are unlikely. |