ZILXI
Clinical safety rating: caution
Comprehensive clinical and safety monograph for ZILXI (ZILXI).
Topical calcineurin inhibitor; inhibits T-cell activation and pro-inflammatory cytokine production by binding to FKBP-12 and inhibiting calcineurin-dependent dephosphorylation of nuclear factor of activated T-cells (NF-AT).
| Metabolism | Hepatic metabolism via CYP3A4 to O-demethylated metabolites (tacrolimus is the active ingredient); topically applied, minimal systemic absorption. |
| Excretion | Primarily renal (70%) as unchanged drug; biliary/fecal (30%) as metabolites and parent compound. |
| Half-life | Terminal elimination half-life: 1.8-2.2 hours in adults; clinically, dosing every 4-6 hours maintains therapeutic levels. |
| Protein binding | 99% bound primarily to albumin; minor binding to α1-acid glycoprotein. |
| Volume of Distribution | 0.1-0.2 L/kg; indicates distribution largely confined to plasma and interstitial fluid. |
| Bioavailability | Topical: ~3-8% systemically absorbed over 24 hours with repeated dosing. No oral formulation. |
| Onset of Action | Topical: Within 15-30 minutes of application. Oral: Not applicable (topical use only). |
| Duration of Action | Analgesic effect lasts 4-6 hours post-application, correlating with dosing interval of 3-4 times daily for acute pain. |
Adults: 0.1% cream applied topically to affected area once daily for 8 weeks.
| Dosage form | AEROSOL, FOAM |
| Renal impairment | No dose adjustment required for renal impairment. |
| Liver impairment | No formal studies; use caution in severe hepatic impairment (Child-Pugh class C). |
| Pediatric use | Children ≥6 years: 0.1% cream applied topically to affected area once daily for 8 weeks. |
| Geriatric use | No specific dose adjustment; use same as adult dosing. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for ZILXI (ZILXI).
| Breastfeeding | Minocycline is excreted into breast milk in small amounts. The milk-to-plasma concentration ratio is approximately 0.5-1.0. Theoretical risks include dental staining and bone growth inhibition in the nursing infant. Due to lack of safety data, discontinue breastfeeding or avoid ZILXI during lactation. Consider alternative topicals if breastfeeding. |
| Teratogenic Risk | ZILXI (minocycline foam) is a tetracycline derivative. Tetracyclines cross the placenta and may cause permanent discoloration of teeth (yellow-gray-brown) and reversible inhibition of bone growth in the fetus if used during the second and third trimesters. Use during the first trimester is associated with a low risk of spontaneous abortion and possibly neural tube defects, but data are limited. Avoid use during pregnancy; alternative therapy is recommended. |
■ FDA Black Box Warning
Rare cases of malignancy (including lymphoma and skin cancer) have been reported in patients treated with topical calcineurin inhibitors. Avoid continuous long-term use. Use only as second-line therapy for short-term and intermittent treatment.
| Serious Effects |
Hypersensitivity to tacrolimus or any component of the formulation; use on Netherton syndrome or skin with impaired barrier function (increased systemic absorption); concomitant use with phototherapy (PUVA, UVB).
| Precautions | Increased risk of infections (varicella zoster, herpes simplex, eczema herpeticum); application site reactions (burning, stinging); lymphadenopathy; photosensitivity; avoid use on malignant or premalignant skin conditions. |
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| Fetal Monitoring | If ZILXI is inadvertently used during pregnancy, no specific fetal monitoring is indicated beyond routine prenatal care. Assess for potential adverse effects on fetal bone and teeth if exposure occurs after the first trimester. |
| Fertility Effects | No specific fertility effects have been reported with topical minocycline. Systemic minocycline has not been associated with impaired fertility in humans. However, animal studies show no significant effects on fertility. No impact on fertility is expected with topical application. |