PROTOPIC
Clinical safety rating: caution
Comprehensive clinical and safety monograph for PROTOPIC (PROTOPIC).
Tacrolimus, a calcineurin inhibitor, binds to FKBP-12 and inhibits calcineurin, thereby blocking dephosphorylation and nuclear translocation of NFAT, reducing transcription of pro-inflammatory cytokines (e.g., IL-2, IFN-γ) in T-cells.
| Metabolism | Primarily hepatic via CYP3A4; also metabolized by CYP3A5. Topical absorption results in minimal systemic exposure, but systemic metabolism follows oral route. |
| Excretion | Primarily fecal (biliary) elimination of metabolites; <1% of parent drug excreted unchanged in urine. |
| Half-life | Terminal half-life ranges from 6–20 hours in pediatric atopic dermatitis patients; prolonged in hepatic impairment (mean 8–35 hours). |
| Protein binding | 99% bound primarily to albumin and alpha-1-acid glycoprotein. |
| Volume of Distribution | Vd/F ~ 30–50 L/kg after oral administration, indicating extensive tissue distribution; topical absorption negligible. |
| Bioavailability | Systemic bioavailability after topical application is <0.5% in adults with intact skin; increases in compromised skin barrier. |
| Onset of Action | Clinical improvement noted within 3–5 days of twice-daily topical application. |
| Duration of Action | Sustained improvement for 1–2 weeks after discontinuation; continuous use recommended for flare management. |
Apply a thin layer of 0.03% or 0.1% ointment to affected areas twice daily. Discontinue when lesions resolve. For adults, use 0.03% or 0.1%; 0.1% is not indicated for children.
| Dosage form | OINTMENT |
| Renal impairment | No dose adjustment required. Tacrolimus is not significantly renally excreted and systemic absorption is minimal. |
| Liver impairment | No specific dose adjustment for Child-Pugh class A or B. For severe hepatic impairment (Child-Pugh C), use with caution; consider starting at lower concentration (0.03%) due to potential increased systemic exposure. |
| Pediatric use | Children (2-15 years): Apply 0.03% ointment twice daily. Do not use 0.1% in this age group. For children 2 years and older. |
| Geriatric use | No specific dose adjustment required. Use minimum effective amount; monitor for cutaneous infections. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for PROTOPIC (PROTOPIC).
| Breastfeeding | Not known if tacrolimus is excreted in human milk after topical administration. Systemic absorption is minimal (<0.5%), but caution is advised due to potential for infant immunosuppression. M/P ratio: not available. Consider benefit of breast-feeding vs risk of infant exposure. |
| Teratogenic Risk | Pregnancy Category C. Animal studies have shown embryotoxicity and teratogenicity at systemic exposures below human therapeutic levels. No adequate human studies in pregnant women. Risk cannot be ruled out; use only if potential benefit justifies potential risk to fetus. First trimester: avoid if possible. Second and third trimesters: limited data; systemic absorption minimal with topical use, but theoretical risk remains. |
■ FDA Black Box Warning
Long-term safety of topical calcineurin inhibitors has not been established. Although a causal relationship has not been established, rare cases of malignancy (e.g., lymphoma, skin cancer) have been reported in patients treated with topical calcineurin inhibitors. Therefore, continuous long-term use should be avoided, and application should be limited to areas of involvement.
| Serious Effects |
Hypersensitivity to tacrolimus or any component of the formulation; use in patients with known or suspected malignancy at the application site; use in immunocompromised patients (relative).
| Precautions | Increased risk of infections (including herpes simplex, eczema herpeticum); avoid use on malignant or premalignant skin conditions; use with caution in patients with netherton syndrome; may cause photosensitivity; avoid concurrent UV exposure; monitor for lymphadenopathy; not for use in children <2 years (safety not established). |
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| Fetal Monitoring | Monitor for maternal skin infections, local irritation, or systemic effects (nephrotoxicity, neurotoxicity) especially with extensive application. Fetal monitoring: usual prenatal care; no specific fetal monitoring required unless maternal systemic toxicity occurs. |
| Fertility Effects | No specific human data on fertility effects. Animal studies show no impairment of fertility at subtoxic doses. Topical use is unlikely to affect fertility due to minimal systemic absorption. |