griseofulvin (Gris-Peg, Grifulvin V)

What is griseofulvin tablet, and how does it work (mechanism of action)?

Griseofulvin is an oral antibiotic that is used to treat fungal infections of the skin, body, hair/beard, or nails. Griseofulvin prevents fungal cells from dividing and multiplying. Griseofulvin also is deposited in keratin cells on the surface of the skin making it difficult for fungus to invade the skin and other tissues. Griseofulvin is effective against Microsporum, Epidermophyton and Trichophyton. It is not effective against bacteria. The FDA approved griseofulvin in 1959.

What brand names are available for griseofulvin tablet?

Gris-Peg, Grifulvin V, Griseofulvin Ultramicrosize

Is griseofulvin tablet available as a generic drug?


Do I need a prescription for griseofulvin tablet?


What are the side effects of griseofulvin tablet?

Reported side effects include:


Ringworm is caused by a fungus. See Answer

What is the dosage for griseofulvin tablet?


  • The recommended dose is 375 mg daily or 250 mg three times daily of the ultramicrosize formulation depending on the type of infection. 
  • The dosing recommendation for the microsize formulation is 500 mg once or twice daily, or 1000 mg as a single dose depending on the type of fungal infection.

The duration of treatment varies and is generally continued until the fungal infection is completed eradicated. It is usually taken for

  • 2 to 4 weeks for skin infections,
  • 4 to 6 weeks for hair and scalp infections,
  • 4 to 8 weeks for foot infections,
  • 3 to 4 months for fingernail infections, and
  • a minimum of at least 6 months for toenail infections.

Which drugs or supplements interact with griseofulvin tablet?

Griseofulvin interacts with many drugs. Patients should consult the prescribing information for a complete list of drugs that interact with griseofulvin. Known drug interactions include:

  • Griseofulvin increases the activity of CYP3A4 liver enzymes. Griseofulvin should not be combined with other drugs that are metabolized (broken down) by CYP3A4 enzymes because griseofulvin may decrease their blood concentrations, decreasing treatment effectiveness. Examples of drugs metabolized by CYP3A4 enzymes include atazanavir (Reyataz), bedaquiline (Sirturo), daclatasvir (Daklinza), darunavir (Prezista), gefitinib (Iressa), nilotinib (Tasigna), palbociclib (Ibrance), telithromycin (Ketek), and several other drugs.
  • Use of griseofulvin with birth control pills may reduce the effectiveness of birth control pills and cause breakthrough bleeding. Patients should use an alternative or additional form of birth control (contraception) while on griseofulvin therapy and for up to 1 month after stopping treatment.
  • The effectiveness of warfarin (Coumadin, Jantoven) may be reduced by griseofulvin because griseofulvin may increase the breakdown warfarin by enzymes in the liver.

Is griseofulvin tablet safe to take if I'm pregnant or breastfeeding?

Griseofulvin is known to cause birth defects and should be avoided during pregnancy. Women of child bearing potential must use appropriate forms of contraception (birth control) during treatment and for one month after completing griseofulvin therapy. Men are advised to wait six months after completing griseofulvin therapy before attempting to father a child.

It is not known whether griseofulvin is excreted into human milk. Due to the lack of conclusive safety data, the manufacturer recommends against the use of griseofulvin in nursing mothers.

What else should I know about griseofulvin tablet?

What preparations of griseofulvin tablet are available?

  • Oral suspension (microsize): 125 mg/5ml
  • Microsize: Oral tablets: 250 mg, 500 mg
  • Ultramicrosize oral tablets: 125 mg, 250 mg,

How should I keep griseofulvin tablet stored?

Griseofulvin should be stored at room temperature, between 15 C and 30 C (59 F and 86 F).


Griseofulvin (Gris-Peg, Grifulvin V, Griseofulvin Ultramicrosize) is an antibiotic prescribed to treat fungal infections such as ringworm of the body, athlete's foot, barber's itch, and fungal or ringworm of the nails. Side effects, drug interactions, dosing, storage, and pregnancy and breastfeeding information should be reviewed prior to taking this medication.

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Medically reviewed by John P. Cunha, DO, FACOEP; Board Certified Emergency Medicine


FDA Prescribing Information