Grisactin 500

Grisactin 500 Overview


Gris-PEG (generic: griseofulvin) is a prescription medication used to treat skin infections such as jock itch, athlete's foot, and ringworm; and fungal infections of the scalp, fingernails, and toenails. This medication belongs to a group of drugs called antifungals. It works by inhibiting the growth of certain fungi that cause infection.

Gris-PEG comes in tablet form. It is usually taken once daily, but can be taken up to 4 times daily. Although symptoms may get better in a few days Gris-PEG 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 at least 6 months for toenail infections.

Common side effects include flushing, nausea, vomiting, and diarrhea. Gris-PEG may cause dizziness. Do not drive or operate heavy machinery until you know how it affects you.

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What are you taking Grisactin 500 for?

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  • Other
  • Tinea Capitis
  • Tinea Pedis

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  • Less than a week
  • A couple weeks
  • A month or so
  • A few months
  • A year or so
  • Two years or more

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Uses of Grisactin 500

Gris-PEG is a prescription medication used for the treatment of the following ringworm infections:

  • tinea corporis (ringworm of the body)
  • tinea pedis (athlete's foot)
  • tinea cruris (ringworm of the groin and thigh) 
  • tinea barbae (barber's itch)
  • tinea capitis (ringworm of the scalp)
  • tinea unguium (onychomycosis, ringworm of the nails)

This medication may be prescribed for other uses. Ask your doctor or pharmacist for more information.


For more information on this medication choose from the list of selections below.

Grisactin 500 Drug Class

Grisactin 500 is part of the drug class:

Side Effects of Grisactin 500

Common side effects include:

  • oral thrush
  • nausea
  • vomiting
  • diarrhea
  • headache
  • fatigue
  • dizziness
  • insomnia
  • mental confusion
  • impairment of performance of routine activities

This is not a complete list of Gris-PEG side effects. Ask your doctor or pharmacist for more information.

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.