JENLOGA
Clinical safety rating: caution
Comprehensive clinical and safety monograph for JENLOGA (JENLOGA).
JENLOGA is a combination of sulfamethoxazole, a sulfonamide, and trimethoprim, a dihydrofolate reductase inhibitor. Sulfamethoxazole inhibits bacterial dihydrofolic acid synthesis by competing with para-aminobenzoic acid, while trimethoprim inhibits dihydrofolate reductase, blocking the conversion of dihydrofolic acid to tetrahydrofolic acid. This sequential blockade produces synergistic bactericidal activity.
| Metabolism | Sulfamethoxazole is primarily metabolized via N-acetylation (N-acetyltransferase 2) and glucuronidation. Trimethoprim is metabolized primarily by oxidative O-demethylation (CYP3A4, CYP1A2) and conjugation. |
| Excretion | Renal (80% as unchanged drug), biliary/fecal (15% as metabolites and unchanged drug) |
| Half-life | Terminal half-life 6-8 hours in healthy adults; prolonged to 12-15 hours in moderate renal impairment (CrCl 30-50 mL/min) |
| Protein binding | 98% bound primarily to albumin |
| Volume of Distribution | 0.15-0.3 L/kg, indicating limited extravascular distribution |
| Bioavailability | Oral: 92% (high first-pass metabolism; extensive absorption) |
| Onset of Action | Oral: 1-2 hours; Intravenous: 15-30 minutes |
| Duration of Action | 8-12 hours for analgesic effect; antihypertensive effect may persist up to 24 hours |
350 mg orally once daily with food.
| Dosage form | TABLET, EXTENDED RELEASE |
| Renal impairment | GFR ≥45 mL/min: no adjustment; GFR 30-44 mL/min: 350 mg every other day; GFR <30 mL/min or ESRD: not recommended. |
| Liver impairment | Child-Pugh A: no adjustment; Child-Pugh B: 200 mg once daily; Child-Pugh C: not recommended. |
| Pediatric use | Not recommended for pediatric patients due to lack of safety and efficacy data. |
| Geriatric use | No specific dose adjustment recommended; monitor renal function closely in patients ≥65 years. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for JENLOGA (JENLOGA).
| Breastfeeding | Not recommended during breastfeeding. M/P ratio not established; drug is excreted in human milk. Potential for serious adverse reactions in nursing infants. |
| Teratogenic Risk | Pregnancy exposure registry data indicate increased risk of major congenital malformations, including neural tube defects, cardiovascular anomalies, and cleft palate, with first-trimester exposure. Second and third trimester exposure may cause fetal growth restriction, oligohydramnios, and neonatal hypoglycemia. |
| Fetal Monitoring |
■ FDA Black Box Warning
Fatal hypersensitivity reactions including Stevens-Johnson syndrome, toxic epidermal necrolysis, fulminant hepatic necrosis, agranulocytosis, aplastic anemia, and other blood dyscrasias have been reported with sulfonamides. JENLOGA is contraindicated in patients with a history of hypersensitivity to sulfonamides or trimethoprim.
| Serious Effects |
["Hypersensitivity to sulfonamides or trimethoprim","History of drug-induced immune thrombocytopenia with prior sulfonamides","Megaloblastic anemia due to folate deficiency","Severe renal impairment (CrCl <15 mL/min) unless for Pneumocystis jirovecii pneumonia treatment","Pregnancy at term and nursing mothers (due to potential for kernicterus in neonates)","Concomitant use with dofetilide (increases risk of arrhythmias)"]
| Precautions | ["Fatal hypersensitivity reactions (Stevens-Johnson syndrome, toxic epidermal necrolysis); discontinue at first sign of rash","Hematologic toxicity including agranulocytosis, aplastic anemia; monitor CBC regularly","Hepatic necrosis; discontinue if signs of liver injury occur","Severe renal impairment (CrCl <15 mL/min); avoid use","Potential for hyperkalemia in patients with renal dysfunction or those on potassium-sparing diuretics","Risk of folate deficiency; monitor folate levels in chronic therapy","Photosensitivity; avoid prolonged sun exposure"] |
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| Monitor serum drug levels, fetal ultrasound for anomalies and growth, and maternal glucose tolerance. Assess amniotic fluid volume during third trimester. |
| Fertility Effects | May impair spermatogenesis and ovulation in animal studies; human data insufficient. Reversible upon discontinuation. |