FULVICIN P/G 165

Clinical safety rating: caution

Comprehensive clinical and safety monograph for FULVICIN P/G 165 (FULVICIN P/G 165).

How it works

Griseofulvin binds to and disrupts microtubule function by inhibiting spindle formation and mitosis in dermatophytes, leading to inhibition of fungal cell division.

What the body does with it

Metabolism	Primarily hepatic, via demethylation and glucuronidation; multiple metabolites; CYP450 involvement not fully characterized.
Excretion	Primarily renal excretion of metabolites; <1% excreted unchanged. Biliary/fecal elimination accounts for ~30% of metabolites.
Half-life	Terminal elimination half-life is approximately 9-24 hours; dependent on formulation and absorption rate. Steady-state achieved within 4-5 days.
Protein binding	90-95% bound to plasma proteins, primarily albumin.
Volume of Distribution	Apparent Vd is 0.5-1.5 L/kg; indicates extensive tissue distribution (skin, hair, nails).
Bioavailability	Oral bioavailability of ultramicrosized formulation (P/G 165) is approximately 80-90%; absorption enhanced by fatty meal.
Onset of Action	Oral: detectable serum levels within 4 hours; clinical improvement in tinea infections may take 1-2 weeks.
Duration of Action	Duration of therapeutic effect post last dose is approximately 2-4 days; entire treatment course typically 4-8 weeks depending on infection site.

Classification & Brands

Dosing & administration

165 mg orally once daily.

Dosage form	TABLET
Renal impairment	No dose adjustment required for renal impairment.
Liver impairment	Contraindicated in patients with severe liver disease; use with caution in mild to moderate hepatic impairment with dose reduction as clinically indicated.
Pediatric use	Not recommended for children under 2 years. For children 2 years and older: 10-20 mg/kg/day in divided doses.
Geriatric use	Use with caution due to increased risk of adverse effects; consider lower starting doses and monitor renal function.

Use during pregnancy

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

Clinical note

Comprehensive clinical and safety monograph for FULVICIN P/G 165 (FULVICIN P/G 165).

Breastfeeding	Excreted in breast milk; M/P ratio not established. Breastfeeding not recommended due to potential for adverse effects in the infant.
Teratogenic Risk	First trimester: Known teratogen in animals; human data limited but suggests increased risk of conjoined twins and other malformations. Second and third trimesters: Potential fetal hepatotoxicity; avoid use.
Fetal Monitoring

Warnings & precautions

■ FDA Black Box Warning

No FDA black box warning exists for griseofulvin.

Side Effect Profile

Serious Effects

Absolute Contraindications

["Hypersensitivity to griseofulvin","Pregnancy or women planning to become pregnant","Porphyria","Hepatic failure","Use with oral contraceptives may reduce contraceptive efficacy"]

Clinical Precautions

Precautions

["Hepatotoxicity: monitor liver function tests","Photosensitivity: avoid prolonged sun exposure","Lupus-like syndrome exacerbation","Blood dyscrasias: monitor CBC with long-term therapy","Potential for teratogenicity; avoid use in pregnancy"]

Clinical Tips & Counseling

Drug interactions

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FULVICIN P/G 165

Clinical safety rating: caution

Comprehensive clinical and safety monograph for FULVICIN P/G 165 (FULVICIN P/G 165).

How it works

Griseofulvin binds to and disrupts microtubule function by inhibiting spindle formation and mitosis in dermatophytes, leading to inhibition of fungal cell division.

What the body does with it

Metabolism	Primarily hepatic, via demethylation and glucuronidation; multiple metabolites; CYP450 involvement not fully characterized.
Excretion	Primarily renal excretion of metabolites; <1% excreted unchanged. Biliary/fecal elimination accounts for ~30% of metabolites.
Half-life	Terminal elimination half-life is approximately 9-24 hours; dependent on formulation and absorption rate. Steady-state achieved within 4-5 days.
Protein binding	90-95% bound to plasma proteins, primarily albumin.
Volume of Distribution	Apparent Vd is 0.5-1.5 L/kg; indicates extensive tissue distribution (skin, hair, nails).
Bioavailability	Oral bioavailability of ultramicrosized formulation (P/G 165) is approximately 80-90%; absorption enhanced by fatty meal.
Onset of Action	Oral: detectable serum levels within 4 hours; clinical improvement in tinea infections may take 1-2 weeks.
Duration of Action	Duration of therapeutic effect post last dose is approximately 2-4 days; entire treatment course typically 4-8 weeks depending on infection site.

Classification & Brands

Dosing & administration

165 mg orally once daily.

Dosage form	TABLET
Renal impairment	No dose adjustment required for renal impairment.
Liver impairment	Contraindicated in patients with severe liver disease; use with caution in mild to moderate hepatic impairment with dose reduction as clinically indicated.
Pediatric use	Not recommended for children under 2 years. For children 2 years and older: 10-20 mg/kg/day in divided doses.
Geriatric use	Use with caution due to increased risk of adverse effects; consider lower starting doses and monitor renal function.

Use during pregnancy

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

Clinical note

Comprehensive clinical and safety monograph for FULVICIN P/G 165 (FULVICIN P/G 165).

Breastfeeding	Excreted in breast milk; M/P ratio not established. Breastfeeding not recommended due to potential for adverse effects in the infant.
Teratogenic Risk	First trimester: Known teratogen in animals; human data limited but suggests increased risk of conjoined twins and other malformations. Second and third trimesters: Potential fetal hepatotoxicity; avoid use.
Fetal Monitoring

Warnings & precautions

■ FDA Black Box Warning

No FDA black box warning exists for griseofulvin.

Side Effect Profile

Serious Effects

Absolute Contraindications

["Hypersensitivity to griseofulvin","Pregnancy or women planning to become pregnant","Porphyria","Hepatic failure","Use with oral contraceptives may reduce contraceptive efficacy"]