NYSTAFORM
Clinical safety rating: caution
Comprehensive clinical and safety monograph for NYSTAFORM (NYSTAFORM).
Nystatin binds to ergosterol in fungal cell membranes, forming pores that disrupt membrane integrity and cause leakage of intracellular contents, leading to fungal cell death.
| Metabolism | Nystatin is not absorbed systemically after topical application; thus, metabolism is minimal and not well characterized. |
| Excretion | Nystatin is not absorbed from the gastrointestinal tract, intact skin, or mucous membranes. After oral administration, it is excreted almost entirely unchanged in feces (over 99%). Minimal renal excretion occurs (less than 1%). |
| Half-life | Plasma half-life is not measurable due to negligible systemic absorption. Topical or oral administration results in local action only; no systemic half-life is clinically relevant. |
| Protein binding | Not applicable due to lack of systemic absorption; negligible binding if any. |
| Volume of Distribution | Not applicable; no systemic distribution occurs. |
| Bioavailability | Oral: Essentially 0% systemic bioavailability due to lack of absorption. Topical and mucosal: Not applicable; drug acts locally. |
| Onset of Action | Oral: Local antifungal effect begins within 24-72 hours. Topical: Relief of symptoms often within 24-48 hours. |
| Duration of Action | Treatment typically continues for 48 hours after clinical cure to prevent relapse. Duration of local antifungal effect persists while drug is in contact with mucosa (e.g., oral suspension should be kept in mouth as long as possible). Topical: Continue for 2 weeks after healing. |
1 tablet (nystatin 100,000 units) orally three times daily after meals. Each tablet should be allowed to dissolve slowly in the mouth.
| Dosage form | OINTMENT |
| Renal impairment | No dose adjustment required for renal impairment; nystatin is not absorbed systemically. |
| Liver impairment | No dose adjustment required for hepatic impairment; nystatin is not absorbed systemically. |
| Pediatric use | Infants: 100,000 units (1 tablet) orally four times daily; older children: same as adult dose. |
| Geriatric use | Same as adult dose; monitor for compliance due to potential swallowing difficulties. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for NYSTAFORM (NYSTAFORM).
| Breastfeeding | Nystatin is poorly absorbed systemically after oral, topical, or vaginal administration, resulting in negligible levels in breast milk. The M/P ratio is not determined due to low plasma concentrations. Considered compatible with breastfeeding. Avoid application of nystatin cream directly to the nipple to prevent infant irritation. |
| Teratogenic Risk | NYSTAFORM (nystatin) is classified as FDA Pregnancy Category C. No adequate and well-controlled studies in pregnant women. Animal studies have not revealed evidence of teratogenicity. Minimal systemic absorption after topical, oral, or vaginal administration reduces fetal exposure risk. First trimester: theoretically low risk due to poor absorption; second and third trimesters: considered safe for use when clinically indicated. |
■ FDA Black Box Warning
No FDA black box warning.
| Serious Effects |
["Hypersensitivity to nystatin or any component of the formulation","Do not use for systemic fungal infections (only topical)"]
| Precautions | ["May cause local irritation, sensitization, or allergic reactions. Discontinue if hypersensitivity occurs.","Avoid contact with eyes.","Use with caution in patients with compromised skin integrity."] |
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| Fetal Monitoring | No specific fetal monitoring required due to minimal systemic absorption. Standard prenatal care. Monitor for maternal adverse effects (rare). |
| Fertility Effects | No known effects on fertility in animal studies. In humans, no data suggest impairment of fertility. |