SYNALAR
Clinical safety rating: caution
Comprehensive clinical and safety monograph for SYNALAR (SYNALAR).
Corticosteroid that binds to the glucocorticoid receptor, leading to inhibition of phospholipase A2, decreased release of arachidonic acid, and reduced synthesis of prostaglandins and leukotrienes. This results in anti-inflammatory, antipruritic, and vasoconstrictive effects.
| Metabolism | Topical corticosteroids are metabolized primarily in the liver via cytochrome P450 enzymes, followed by renal excretion of metabolites. |
| Excretion | Renal: <1% as unchanged drug; biliary/fecal: minimal; primarily hepatic metabolism with metabolites excreted renally. |
| Half-life | Terminal elimination half-life: 1-2 hours (topical use); 3-4 hours (systemic absorption after topical application to large areas or occluded skin). Clinical context: short half-life allows once- or twice-daily dosing. |
| Protein binding | 90-95% bound to corticosteroid-binding globulin (CBG) and albumin. |
| Volume of Distribution | Systemic: ~1.4 L/kg; indicates extensive tissue distribution, but clinical relevance is minimal for topical use. |
| Bioavailability | Topical: 1-5% systemic absorption through intact skin; higher (up to 30%) with occlusion or damaged skin. |
| Onset of Action | Topical: rapid, within 1-2 hours for anti-inflammatory effect. |
| Duration of Action | Topical: 12-24 hours after single application; clinical effect persists for 12 hours, allowing twice-daily dosing. |
| Molecular Weight | 434.5 |
Apply a thin layer to affected area twice daily. Max 60 g/week.
| Dosage form | CREAM |
| Renal impairment | No dosage adjustment required for topical use. |
| Liver impairment | No dosage adjustment required for topical use. |
| Pediatric use | Apply a thin layer to affected area once or twice daily; limit treatment duration to 2 weeks. Use lowest potency formulation. |
| Geriatric use | Use with caution; apply sparingly to limited areas due to increased risk of skin atrophy and systemic absorption. |
| 1st trimester | Limited human data; topical corticosteroids are generally considered low risk if used sparingly on small areas. Avoid high potency on large areas. |
| 2nd trimester | No known increased risk of congenital defects with topical use; avoid prolonged use on large areas. |
| 3rd trimester | Prolonged use may cause fetal growth restriction or adrenal suppression; avoid excessive amounts or high potency. |
Clinical note
Comprehensive clinical and safety monograph for SYNALAR (SYNALAR).
| Placental transfer | Demonstrated in animal studies; in humans, topical corticosteroids cross placenta in small amounts, increasing with higher potency and larger application areas. |
| Breastfeeding | Topical application to breast area should be avoided to prevent infant ingestion. Systemic absorption is minimal with short-term, small-area use. |
■ FDA Black Box Warning
None
| Serious Effects |
Hypersensitivity to any componentUntreated bacterial, fungal, or viral skin infections
| Precautions | Systemic absorption can cause reversible hypothalamic-pituitary-adrenal (HPA) axis suppression, Cushing's syndrome, hyperglycemia, and glucosuria., Use on large body surface areas, prolonged use, or occlusive dressings increases systemic absorption., May increase risk of local infections if used on infected skin., Not for ophthalmic use., Pediatric patients may be more susceptible to systemic toxicity due to higher skin surface-to-body-mass ratio. |
| Food/Dietary | No known food interactions. Avoid excessive alcohol consumption as it may exacerbate skin conditions. |
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| Lactation Rating | L2 |
| Teratogenic Risk | Topical corticosteroids like Synalar (fluocinolone acetonide) generally result in minimal systemic absorption; however, prolonged or extensive use may increase risk. In animal studies, corticosteroids have shown teratogenic effects. In humans, data are limited but large doses applied topically may slightly increase risk of oral clefts in first trimester. Use during pregnancy only if potential benefit justifies fetal risk, and avoid extensive areas, prolonged use, or occlusive dressings. |
| Fetal Monitoring | Monitor for signs of maternal adrenal suppression if used over large areas or for prolonged periods. No specific fetal monitoring required with short-term topical use; however, if used extensively, consider monitoring for fetal growth restriction via ultrasound. |
| Fertility Effects | No known adverse effects on fertility from topical use. Systemic corticosteroids may affect sperm motility or ovulatory function at high doses, but topical application is unlikely to reach concentrations sufficient to impact fertility. |
| Clinical Pearls |
| SYNALAR (fluocinolone acetonide) is a high-potency topical corticosteroid. Use for short-term treatment (≤2 weeks) on limited body surface area (<10%). Avoid on face, groin, axillae, and intertriginous areas due to increased absorption/risk of atrophy. Do not use with occlusive dressings unless directed for severe conditions. Monitor for HPA axis suppression with prolonged use or large surface areas. |
| Patient Advice | Apply a thin layer only to affected areas; do not use on broken skin or infections. · Wash hands before and after application unless treating hands. · Do not cover the area with bandages or wraps unless prescribed; do not use for diaper rash. · Avoid contact with eyes, nose, and mouth. · Report any signs of skin infection, thinning, or unusual irritation. · Use exactly as directed; do not use longer than prescribed to avoid side effects. |