Griseofulvin is an oral antifungal derived from Penicillium griseofulvum and has been in clinical use since the 1950s. It is used exclusively to treat dermatophyte fungal infections like infections of the skin, hair, and nails caused by Trichophyton, Microsporum and Epidermophyton species. In India, it remains widely prescribed for scalp ringworm (tinea capitis) in children, where it is one of the few oral antifungals available as a paediatric suspension. For better absorption it must be taken with a fatty meal to be absorbed adequately.

Drug Class and How It Differs from Antibiotics

Griseofulvin is an antifungal, not an antibiotic. Antibiotics target bacteria whereas antifungals target fungi, which are biologically entirely different organisms - fungi have a cell structure closer to human cells than to bacteria, requiring antifungal drugs with specific mechanisms that spare human cells. Griseofulvin has no activity against bacteria, viruses or non-dermatophyte fungi such as Candida. It is fungistatic - it stops fungal cells from dividing rather than killing them and therefore requires a prolonged treatment course to be effective.

Fungal Infections Griseofulvin Is Used to Treat

Griseofulvin is approved for dermatophyte infections of the following areas:

• Scalp: Tinea capitis (ringworm of the scalp), including kerion (inflammatory variant); most common indication in children

• Body and groin: Tinea corporis (ringworm of the body) and tinea cruris (jock itch); used when topical treatment has failed

• Feet: Tinea pedis (athlete's foot); less commonly used now due to terbinafine availability

• Nails: Tinea unguium (onychomycosis); less effective than terbinafine and itraconazole for nail fungus

• Beard area: Tinea barbae; deep follicular infection requiring oral rather than topical treatment

Griseofulvin is not effective against Candida, Malassezia or non-dermatophyte moulds.

How Griseofulvin Works (Mechanism of Action)

Griseofulvin disrupts fungal cell division by binding to tubulin - the protein that forms the mitotic spindle. This prevents normal spindle assembly, arresting fungal reproduction. Griseofulvin is selectively taken up by keratin-producing cells (keratinocytes) in the skin, hair and nails. Once deposited in newly forming keratin, it creates an antifungal environment in outgrowing hair shafts and nails. Because the drug is incorporated into new keratin but not existing infected keratin so it works from the inside outward as old infected tissue is shed and replaced.

Available Forms and Treatment Duration

Griseofulvin is available in microsize tablets (125 mg, 250 mg, 500 mg) and ultramicrosize tablets, which achieve better gastrointestinal absorption at two-thirds the microsize dose. In India, tablets (ultramicrosize, 250 mg and 500 mg) and oral suspension (125 mg per 5 mL) are widely available. Standard adult dosing is 500 mg to 1000 mg daily (microsize); for children, dosing is weight-based at approximately 10 to 15 mg/kg/day. Treatment duration varies: tinea corporis requires 4 to 6 weeks; tinea capitis requires 6 to 12 weeks; tinea unguium requires 6 to 12 months for fingernails and up to 18 months for toenails.

Side Effects of Griseofulvin

Mild side effects include:

• Headache (particularly during the first weeks, usually resolving without stopping the drug)

• Nausea and vomiting

• Abdominal discomfort

• Diarrhoea

• Photosensitivity and rash occur in some patients; prolonged sun exposure should be avoided during treatment.

Serious but uncommon side effects include:

• Hepatotoxicity

• Leucopenia (low white blood cell count) 

• Neurological effects including peripheral neuropathy have been reported with high doses.

Who Should Not Take Griseofulvin?

Certain groups of people should avoid griseofulvin. They are:

• Pregnant women

• Patients with porphyria 

• Patients with severe hepatic impairment or active liver disease

• Patients with known hypersensitivity to griseofulvin or to penicillin 

• Patients on warfarin.

Drug Interactions

Griseofulvin is a potent inducer of hepatic cytochrome P450 enzymes (CYP3A4 and CYP1A2), significantly reducing the plasma concentrations and efficacy of several important drugs:

• Oral contraceptives

• Warfarin 

• Cyclosporin 

• Barbiturates and phenobarbitone 

• Alcohol.

Griseofulvin vs Terbinafine vs Fluconazole - Which Is Better?

Terbinafine is now the preferred oral antifungal for most dermatophyte infections in adults - it is fungicidal, achieves cure in shorter treatment courses and has a better safety profile for long-term use. For tinea capitis in children caused by Microsporum species (common in India), griseofulvin retains an advantage, as terbinafine is significantly less effective against Microsporum than against Trichophyton. Fluconazole is more useful for Candida infections and is not routinely preferred for tinea. Griseofulvin's low cost and widespread availability in India make it the first-line choice for tinea capitis in children in many clinical settings.

Why It Should Be Taken with Fatty Food

Griseofulvin is highly lipophilic so it dissolves in fat rather than water. Taken on an empty stomach, bioavailability is as low as 25 to 30% but taken with a fatty meal like ghee, full-fat milk, groundnut chikki, peanuts, eggs or any oily sabzi bioavailability increases to 70 to 80%. Taking griseofulvin with full-fat milk or a meal cooked with ghee is the simplest practical approach for Indian patients. The ultramicrosize formulation has better baseline absorption but the food interaction remains clinically relevant for both formulations.

FAQs

1. What fungal infections does griseofulvin treat?

   Griseofulvin treats dermatophyte fungal infections including infections of the skin, hair, and nails caused by Trichophyton, Microsporum, and Epidermophyton species. This includes tinea capitis (scalp ringworm), tinea corporis (body ringworm), tinea cruris (groin), tinea pedis (feet), tinea barbae (beard) and tinea unguium (nail fungus). It has no activity against Candida, pityriasis versicolor or bacterial infections.

2. How long does griseofulvin take to cure a fungal infection?

   Treatment duration depends on infection site. 

   • Tinea corporis requires 4 to 6 weeks

   • Tinea capitis requires 6 to 12 weeks

   • Nail fungus requires 6 to 12 months for fingernails and up to 18 months for toenails. 

   The full course must be completed even when the skin or scalp appears clear, as griseofulvin works by being incorporated into new growing keratin and stopping early leaves residual fungal elements that cause recurrence.

3. Why is griseofulvin taken with fatty or oily food?

   Griseofulvin is lipophilic means it dissolves in fat and absorption depends directly on the fat content of food consumed with it. Therefore take it with a fatty meal like full-fat milk, ghee, eggs, or any oily sabzi for better bioavailability. Taking griseofulvin with a glass of full-fat milk or a meal with ghee is the simplest approach for most Indian patients.

4. Can griseofulvin affect birth control pills?

   Yes griseofulvin accelerates the liver's metabolism of oestrogen and progestogen, reducing the effective plasma concentration of combined oral contraceptive pills. This can lead to contraceptive failure and unintended pregnancy. Women taking oral contraceptives must use additional non-hormonal contraception (condoms) throughout griseofulvin treatment and for at least one month after stopping. This interaction applies to both combined pills and progestogen-only pills.

5. Is griseofulvin safe for children with ringworm?

   Yes griseofulvin is well-established for use in children and is one of the few oral antifungals available as a paediatric suspension (125 mg per 5 mL). It is the first-line oral treatment for tinea capitis in children particularly for Microsporum species, which are common in India and respond less well to terbinafine. Dosing is weight-based at approximately 10 to 15 mg/kg/day; the most common side effects are headache and gastrointestinal discomfort.

6. What happens if you stop griseofulvin too early?

   Stopping griseofulvin before the prescribed duration is the most common cause of treatment failure and recurrence. Griseofulvin is incorporated into new keratin as it grows and it does not eradicate fungi already present in existing infected keratin. Residual fungal elements in infected skin, hair or nails survive and re-establish infection once drug levels fall. 

7. Can griseofulvin cause liver damage?

   Hepatotoxicity with griseofulvin is uncommon but documented, particularly with prolonged treatment or pre-existing liver disease. Patients with active liver disease should not take griseofulvin. For courses extending beyond 3 months as required for nail infections periodic liver function monitoring is advisable. 

8. Is griseofulvin still used when newer antifungals are available?

   Yes. Its primary advantage is efficacy against Microsporum species causing tinea capitis in children, where terbinafine has significantly lower cure rates. It is also widely available at low cost across India, making it accessible in primary care and public health settings. For adult dermatophyte infections, terbinafine is generally preferred.

9. Can griseofulvin treat nail fungus?

   Technically yes, but it is not the preferred choice. Griseofulvin requires 6 to 12 months for fingernail fungus and up to 18 months for toenail fungus far longer than terbinafine (6 weeks for fingernails, 12 weeks for toenails) or itraconazole pulse therapy. Cure rates with griseofulvin for onychomycosis are also lower than with terbinafine. Griseofulvin may be used for nail fungus where terbinafine and itraconazole are contraindicated or unavailable but it is not standard first-line therapy.

10. Does alcohol interact badly with griseofulvin?

    Yes concurrent alcohol consumption during griseofulvin treatment causes a disulfiram-like reaction in some patients like flushing, rapid heart rate, sweating and headache. Patients should avoid alcohol during griseofulvin treatment. Alcohol-related liver disease also increases the hepatotoxicity risk of griseofulvin, providing a further reason to abstain during the treatment course.

References

1. Gupta AK, Drummond-Main C. Meta-analysis of randomised, controlled trials comparing particular doses of griseofulvin and terbinafine for the treatment of tinea capitis. Pediatr Dermatol. 2013;30(1):1–6. https://doi.org/10.1111/j.1525-1470.2012.01866.x

2. Hay RJ. Tinea capitis: current status. Mycopathologia. 2017;182(1–2):87–93. https://doi.org/10.1007/s11046-016-0058-8

3. Favre B, Hofbauer B, Hildering KS, Ryder NS. Comparison of in vitro activities of 17 antifungal drugs against a panel of 20 dermatophytes by using a micro-dilution assay. J Clin Microbiol. 2003;41(10):4817–19. https://doi.org/10.1128/JCM.41.10.4817-4819.2003

4. Singal A, Khanna D. Onychomycosis: diagnosis and management. Indian J Dermatol Venereol Leprol. 2011;77(6):659–72. https://doi.org/10.4103/0378-6323.86475

5. Petranyi G, Ryder NS, Stutz A. Allylamine derivatives: new class of synthetic antifungal agents inhibiting fungal squalene epoxidase. Science. 1984;224(4654):1239–41. https://doi.org/10.1126/science.6547247