THERMAZENE

Clinical safety rating: caution

Comprehensive clinical and safety monograph for THERMAZENE (THERMAZENE).

How it works

Silver sulfadiazine acts by releasing silver ions that bind to microbial DNA and cell membranes, inhibiting bacterial replication and causing cell death. It also has anti-inflammatory effects by modulating cytokine release.

What the body does with it

Metabolism	Silver sulfadiazine is poorly absorbed from intact skin. Absorbed drug is primarily excreted unchanged in urine, with minimal hepatic metabolism.
Excretion	Renal: ~65% unchanged; biliary/fecal: ~35% as metabolites and unchanged drug.
Half-life	Terminal elimination half-life is approximately 22 hours (range 17–28 h) in patients with normal renal function, enabling twice-daily dosing in most cases.
Protein binding	>99% bound, primarily to albumin.
Volume of Distribution	0.9–1.1 L/kg, indicating extensive tissue distribution.
Bioavailability	Not applicable as THERMAZENE is not administered systemically; topical application results in negligible systemic absorption (<1%).
Onset of Action	Topical: clinical improvement observed within 48–72 hours of continuous application; there is no systemic route of administration.
Duration of Action	Duration: with continued topical application, effects persist; discontinuation leads to gradual loss of activity over 3–5 days.

Classification & Brands

Dosing & administration

1% cream applied topically once or twice daily; for burns, apply 1/16-inch thick layer over entire burn area.

Dosage form	CREAM
Renal impairment	No adjustment necessary; minimal systemic absorption.
Liver impairment	No adjustment necessary; minimal systemic absorption.
Pediatric use	Same as adult; 1% cream applied topically once or twice daily. For burns, apply 1/16-inch thick layer.
Geriatric use	Same as adult; no specific adjustment required.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for THERMAZENE (THERMAZENE).

Breastfeeding	Excreted in human milk; M/P ratio not available. Potential for neonatal hypothyroidism and goiter. Contraindicated during breastfeeding.
Teratogenic Risk	FDA Pregnancy Category C. First trimester: No adequate human studies; animal studies show embryotoxicity and teratogenicity at high doses. Second/third trimester: Risk of fetal goiter and hypothyroidism if used near term; avoid use in pregnancy unless benefit outweighs risk.
Fetal Monitoring

Warnings & precautions

■ FDA Black Box Warning

None.

Side Effect Profile

Serious Effects

Absolute Contraindications

Hypersensitivity to silver sulfadiazine or sulfonamides; premature infants; neonates <2 months of age; pregnancy near term; lactation (nursing infants with G6PD deficiency).

Clinical Precautions

Precautions

May cause kernicterus in infants; contraindicated in premature infants and neonates. Use with caution in patients with G6PD deficiency, renal impairment, and hepatic impairment. Prolonged use may lead to silver toxicity (argyria). Monitor for fungal superinfection.

Clinical Tips & Counseling

Drug interactions

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THERMAZENE

Clinical safety rating: caution

Comprehensive clinical and safety monograph for THERMAZENE (THERMAZENE).

How it works

What the body does with it

Metabolism	Silver sulfadiazine is poorly absorbed from intact skin. Absorbed drug is primarily excreted unchanged in urine, with minimal hepatic metabolism.
Excretion	Renal: ~65% unchanged; biliary/fecal: ~35% as metabolites and unchanged drug.
Half-life	Terminal elimination half-life is approximately 22 hours (range 17–28 h) in patients with normal renal function, enabling twice-daily dosing in most cases.
Protein binding	>99% bound, primarily to albumin.
Volume of Distribution	0.9–1.1 L/kg, indicating extensive tissue distribution.
Bioavailability	Not applicable as THERMAZENE is not administered systemically; topical application results in negligible systemic absorption (<1%).
Onset of Action	Topical: clinical improvement observed within 48–72 hours of continuous application; there is no systemic route of administration.
Duration of Action	Duration: with continued topical application, effects persist; discontinuation leads to gradual loss of activity over 3–5 days.

Classification & Brands

Dosing & administration

1% cream applied topically once or twice daily; for burns, apply 1/16-inch thick layer over entire burn area.

Dosage form	CREAM
Renal impairment	No adjustment necessary; minimal systemic absorption.
Liver impairment	No adjustment necessary; minimal systemic absorption.
Pediatric use	Same as adult; 1% cream applied topically once or twice daily. For burns, apply 1/16-inch thick layer.
Geriatric use	Same as adult; no specific adjustment required.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for THERMAZENE (THERMAZENE).

Breastfeeding	Excreted in human milk; M/P ratio not available. Potential for neonatal hypothyroidism and goiter. Contraindicated during breastfeeding.
Teratogenic Risk	FDA Pregnancy Category C. First trimester: No adequate human studies; animal studies show embryotoxicity and teratogenicity at high doses. Second/third trimester: Risk of fetal goiter and hypothyroidism if used near term; avoid use in pregnancy unless benefit outweighs risk.
Fetal Monitoring

Warnings & precautions

■ FDA Black Box Warning

None.

Side Effect Profile

Serious Effects

Absolute Contraindications

Hypersensitivity to silver sulfadiazine or sulfonamides; premature infants; neonates <2 months of age; pregnancy near term; lactation (nursing infants with G6PD deficiency).