Griso500 mg

Approved / Established Uses

Griso is an oral antifungal agent indicated for the treatment of dermatophyte (ringworm) infections of the skin, hair, and nails caused by susceptible species of Trichophyton, Microsporum, and Epidermophyton, when the infection is extensive, chronic, or otherwise inadequately responsive to topical antifungal therapy alone. Established indications include:

• Tinea capitis (ringworm of the scalp) — this is the classic, best-established indication for Griso, since topical agents alone cannot penetrate the hair follicle.
• Tinea corporis (ringworm of the body)
• Tinea cruris (jock itch)
• Tinea pedis (athlete's foot), particularly chronic or extensive infection
• Tinea barbae (ringworm of the beard area)
• Onychomycosis / tinea unguium (fungal nail infection) caused by susceptible dermatophytes, when topical therapy is inadequate — although newer oral antifungals are generally preferred first-line for nails due to shorter treatment duration and higher cure rates.

Not Effective For

Griso has no activity against bacteria, yeasts (including Candida), or other fungi outside the dermatophyte group, and should not be used for these infections.

Each formulation of Griseofulvin [Microsize] contains griseofulvin in a microsize (finely micronized) particle form as the active pharmaceutical ingredient, which increases the surface area of the drug and improves its absorption from the gastrointestinal tract compared to non-micronized griseofulvin. Griseofulvin [Microsize] is typically available as film-coated tablets and as an oral suspension, along with standard pharmaceutical excipients such as binders, fillers, and preservatives (for the suspension).

Griso is a systemic (oral) antifungal antibiotic originally derived from the mold Penicillium griseofulvum. It is fungistatic (inhibits fungal growth rather than directly killing the organism) and is used specifically for infections caused by dermatophyte fungi affecting the skin, hair, and nails. Because it must be deposited into newly forming keratin to work, Griso requires the affected keratin (skin, hair, or nail) to grow out and be replaced, which is why treatment courses are often prolonged.

Griso is used only when topical antifungal treatment is impractical or has failed, since oral therapy carries a greater potential for systemic side effects and drug interactions than topical agents.

Systemic (oral) antifungal agent — Griso belongs to a distinct chemical class of fungistatic antifungals unrelated to the azole, polyene, or allylamine classes.

Mechanism of Action

Griseofulvin [Microsize] is fungistatic against susceptible dermatophytes. It is deposited in keratin precursor cells of the skin, hair, and nails; as these cells differentiate into keratin, the drug renders the new keratin resistant to fungal invasion. Griseofulvin [Microsize] also binds to fungal microtubular proteins, disrupting the mitotic spindle and interfering with fungal cell mitosis, which halts fungal cell division and growth.

Pharmacokinetics

Absorption of the microsize form of Griseofulvin [Microsize] is variable and is enhanced when taken with a fatty meal. Once absorbed, the drug concentrates in the stratum corneum and keratinous tissues. It is metabolized in the liver and excreted mainly in the urine and feces as metabolites.

Griso should be taken with or immediately after a meal — preferably one containing some fat — as this significantly increases absorption of the microsize formulation. Tablets should be swallowed whole or as directed; the oral suspension should be shaken well and measured with an accurate dosing device. Doses should be taken at the same time(s) each day to maintain consistent blood levels.

Clinically Significant Interactions

• Warfarin and other oral anticoagulants: Griso induces hepatic enzymes that can reduce the anticoagulant effect of warfarin. Patients on concurrent therapy require closer INR monitoring and possible warfarin dose adjustment.
• Hormonal contraceptives (oral contraceptive pills): Griso can reduce the effectiveness of estrogen-containing oral contraceptives, leading to breakthrough bleeding and risk of contraceptive failure. Patients should be advised to use an additional or alternative method of contraception during treatment and for one menstrual cycle after stopping Griso.
• Phenobarbital and other enzyme-inducing anticonvulsants: Phenobarbital reduces gastrointestinal absorption of Griso, lowering its blood levels and antifungal effect; dose separation or dose adjustment of Griso may be needed if concurrent use cannot be avoided.
• Alcohol: Concurrent alcohol intake with Griso may provoke a disulfiram-like reaction (flushing, tachycardia) or enhanced sensitivity to alcohol's effects; patients should be advised to limit or avoid alcohol during treatment.

The most common side effect of Griso is headache, which occurs frequently, especially early in treatment, and often diminishes with continued use.

Common

• Headache
• Gastrointestinal upset — nausea, vomiting, diarrhea, epigastric discomfort
• Photosensitivity (increased sensitivity of the skin to sunlight)

Less Common / Rare

• Skin rash, urticaria (hives)
• Hepatotoxicity (rare, usually mild and reversible; very rarely serious)
• Hypersensitivity reactions, including rare severe skin reactions
• Leukopenia (reduced white blood cell count)
• Confusion, impaired coordination, fatigue (rare)
• Exacerbation of systemic lupus erythematosus (rare)

Pregnancy: Griso is contraindicated during pregnancy. It has demonstrated teratogenic and embryotoxic effects in animal studies, and its use is well-established as unsafe in human pregnancy. Griso must not be used by pregnant women or by women planning pregnancy. Effective contraception should be used during treatment and for at least one month after stopping Griso in women; male patients are generally advised to avoid fathering a child during treatment and for a period afterward, per prescribing guidance.

Lactation: Griso passes into breast milk. Because of the potential for adverse effects in the nursing infant, Griso should be avoided during breastfeeding; a physician should be consulted to weigh alternatives.

• Contraception: Effective non-hormonal or backup contraception is recommended during treatment with Griso and for a period after stopping, given reduced efficacy of hormonal contraceptives and the drug's teratogenic potential (see Interactions and Pregnancy and Lactation).
• Photosensitivity: Griso can increase skin sensitivity to sunlight; patients should minimize sun exposure, use sun protection, and report severe sunburn-like reactions to their physician.
• Liver function monitoring: Periodic monitoring of liver function is advisable with prolonged courses of Griso, particularly in patients with pre-existing liver conditions or those on other hepatotoxic drugs.
• Penicillin sensitivity: Since Griso is derived from a Penicillium mold species, it should be used with caution in patients with known penicillin allergy, as rare cross-sensitivity has been reported.
• Effects on alertness: Griso may rarely cause confusion or impaired coordination; patients should exercise caution when driving or operating machinery until they know how they respond to the medicine.
• Blood monitoring: Periodic complete blood counts are advisable during prolonged therapy.

Specific data on Griso overdose are limited. Suspected overdose may cause exaggerated side effects such as headache, gastrointestinal upset, or allergic-type reactions. There is no specific antidote. If an overdose of Griso is suspected, seek immediate medical attention or contact a poison control center; supportive and symptomatic treatment should be provided by medical professionals. Do not attempt to manage a suspected overdose at home without professional medical guidance.

Store at room temperature (below 30°C), protected from light and moisture. Keep out of reach of children.

Hepatic Impairment

Griso is metabolized by the liver and is contraindicated in patients with severe hepatocellular failure; use with caution and monitor liver function in patients with milder hepatic impairment (see Contraindications and Precautions and Warnings).

Renal Impairment

No specific dose adjustment is well-established for renal impairment, as Griso is primarily hepatically metabolized; it should still be used with medical judgment in patients with significant renal disease.

Elderly

No specific dose adjustment is established for elderly patients; use with routine clinical monitoring, particularly for hepatic function.

Pediatric Patients

See Pediatric Uses for age- and weight-based dosing guidance.

Duration of Griso therapy depends on the site of infection and must continue until the infected skin, hair, or nail is fully replaced by healthy tissue:

• Tinea corporis / cruris: typically 2–4 weeks
• Tinea capitis: typically 4–8 weeks or longer, guided by clinical and mycological response
• Tinea pedis: typically 4–8 weeks
• Onychomycosis of fingernails: at least 4 months
• Onychomycosis of toenails: at least 6 months, sometimes longer

Treatment with Griso should not be stopped early even if symptoms resolve, as premature discontinuation risks relapse.

Griseofulvin [Microsize] belongs to the class of systemic antifungal agents; specifically it is a fungistatic, non-azole, non-polyene, non-allylamine oral antifungal antibiotic derived from Penicillium species.

Griseofulvin [Microsize] acts by depositing in keratin precursor cells, making newly formed keratin resistant to fungal invasion, and by binding fungal microtubular proteins to disrupt the mitotic spindle, thereby arresting fungal cell division (fungistatic action) against susceptible dermatophytes.

X

Griso is used in children for dermatophyte infections, most notably tinea capitis, using weight-based dosing determined by a physician. Safety and efficacy of Griso in children under 2 years of age have not been well established, and use in this age group should only occur under close medical supervision when the potential benefit justifies the potential risk. As with adults, the full prescribed course must be completed to prevent relapse.