NYSTEX
Clinical safety rating: caution
Comprehensive clinical and safety monograph for NYSTEX (NYSTEX).
Nystatin binds to ergosterol in fungal cell membranes, forming pores that disrupt membrane integrity and lead to leakage of intracellular contents and cell death.
| Metabolism | Nystatin is not absorbed systemically; it is excreted unchanged in feces. |
| Excretion | Primarily fecal (>95%) as unchanged drug; minimal renal excretion (<1%). |
| Half-life | Variable; estimated 2-5 hours for systemic absorption (if any), but negligible systemic levels due to poor absorption. |
| Protein binding | >90% (bound to plasma proteins, primarily albumin). |
| Volume of Distribution | Negligible systemic Vd; estimable at >100 L/kg if systemic, but not clinically relevant due to poor absorption. |
| Bioavailability | Oral: <5% (negligible systemic absorption); topical: minimal (acts locally, <0.1% absorbed). |
| Onset of Action | Oral: 24-72 hours for antifungal effect; topical: 24-48 hours for symptomatic relief. |
| Duration of Action | Oral: up to 3-5 days after cessation; topical: continues as long as applied, with effects lasting 24-48 hours after last dose. |
| Molecular Weight | 926.09 |
Topical: Apply thin layer to affected area twice daily. Oral suspension (nystatin): 500,000-1,000,000 units (5-10 mL) four times daily for candidiasis. Vaginal tablets: 1 tablet (100,000 units) intravaginally once daily for 14 days.
| Dosage form | SUSPENSION |
| Renal impairment | No dosage adjustment required for renal impairment. |
| Liver impairment | No dosage adjustment required for hepatic impairment. |
| Pediatric use | Oral suspension: Neonates 100,000 units (1 mL) four times daily; Infants 200,000 units (2 mL) four times daily; Children 400,000-600,000 units (4-6 mL) four times daily. Topical: same as adults. |
| Geriatric use | No specific adjustment; use adult dosing with caution for swallowing difficulties; consider oral suspension. |
| 1st trimester | Nystatin is poorly absorbed orally and is considered safe in pregnancy; no evidence of teratogenicity. |
| 2nd trimester | No known fetal harm; topical use preferred over systemic. |
| 3rd trimester | No known risk; safe for use near term. |
Clinical note
Comprehensive clinical and safety monograph for NYSTEX (NYSTEX).
| Placental transfer | Minimal to none due to poor oral absorption; negligible systemic levels. |
| Breastfeeding | Oral nystatin is not absorbed from the GI tract; minimal excretion into breast milk is expected. Topical use is compatible with breastfeeding. Avoid application to nipple to prevent infant ingestion of excess. |
| Lactation Rating |
■ FDA Black Box Warning
No FDA black box warnings.
| Serious Effects |
Hypersensitivity to nystatin or any component of the formulation
| Precautions | Use with caution in patients with hypersensitivity to nystatin; discontinue if irritation or sensitization occurs; not for systemic use; avoid contact with eyes. |
| Food/Dietary | Avoid food or drink for 30 minutes after dosing to maximize contact time. No significant dietary restrictions. |
| Clinical Pearls | NYSTEX is a nystatin-based oral suspension for candidiasis. Shake well before use; swish and swallow for oral thrush. For esophageal candidiasis, use 500,000 units q6h. Monitor for mucosal irritation. Prolonged use may lead to resistance. |
Loading safety data…
| L1 (Safe) |
| Teratogenic Risk | Nystatin is classified as FDA Pregnancy Category C. No teratogenic effects have been reported in animal studies, but adequate human studies are lacking. Minimal systemic absorption after topical, oral, or vaginal use suggests low fetal risk. Trimester-specific risks: First trimester: insufficient data; second and third trimesters: no known increase in congenital anomalies or adverse outcomes. |
| Fetal Monitoring | No specific maternal or fetal monitoring required for nystatin use. Standard prenatal care is sufficient. Monitor for local irritation or allergic reactions. In pregnant women with vaginal candidiasis, clinical resolution of symptoms should be assessed. |
| Fertility Effects | No known adverse effects on fertility. Nystatin is not systemically absorbed and does not alter hormonal profiles or gamete function. Animal studies have not shown impaired fertility. |
| Patient Advice | Shake the bottle vigorously before each dose. · Swish the medication in your mouth for as long as possible before swallowing. · Do not eat or drink for 30 minutes after taking the dose. · Complete the full course even if symptoms improve. · Store at room temperature away from light and moisture. |