Griseofulvin is an antifungal medication used to treat fungal infections of the skin, hair, and nails [1]. It is particularly effective against dermatophytes, the fungi that cause conditions such as ringworm and athlete's foot [2]. The drug works by binding to fungal cell microtubules, disrupting cell division and preventing fungal growth [3].
How does griseofulvin work to treat fungal infections?
Griseofulvin functions by inhibiting mitosis in fungal cells. It accumulates in the keratin of the skin, hair, and nails, making these tissues resistant to fungal invasion [3]. The drug is fungistatic, meaning it stops fungal growth rather than killing the fungi outright. New keratin growth, free from infection, eventually replaces the infected tissue [1].
What types of fungal infections is griseofulvin used for?
Griseofulvin is primarily prescribed for superficial fungal infections that have not responded to topical treatments [2]. This includes infections like:
* Tinea capitis (ringworm of the scalp) [4]
* Tinea corporis (ringworm of the body) [4]
* Tinea cruris (jock itch) [4]
* Tinea pedis (athlete's foot) [4]
* Tinea unguium (onychomycosis, fungal nail infections) [4]
What are the different forms of griseofulvin available?
Griseofulvin is available in tablet and capsule forms, with dosages typically ranging from 125 mg to 500 mg [1]. It is also formulated as a microsize and ultramicrosize suspension for pediatric use or for patients who have difficulty swallowing tablets or capsules [5]. The ultramicrosize particles are absorbed more readily, potentially allowing for lower doses or shorter treatment durations [5].
What is the typical dosage and duration of griseofulvin treatment?
Dosages vary based on the severity of the infection, the patient's age, and the specific formulation used (microsize or ultramicrosize). For adults, a common dose of ultramicrosize griseofulvin is 330 mg once daily, or 165 mg twice daily [1]. For microsize griseofulvin, the dose might be higher, such as 500 mg to 1000 mg per day, often divided into two doses [1]. Treatment duration can range from two weeks to several months, depending on the site and extent of the fungal infection, with nail infections typically requiring the longest treatment periods [4].
Are there any side effects associated with griseofulvin?
Common side effects of griseofulvin can include gastrointestinal issues like nausea, vomiting, and diarrhea, as well as headaches, dizziness, and skin rashes [1][6]. Less common but more serious side effects may involve liver dysfunction, severe skin reactions, and effects on the blood [6]. Patients with a history of liver disease or certain blood disorders should use griseofulvin with caution [6].
When does the patent for griseofulvin expire?
Griseofulvin is a very old drug and is no longer under patent protection. Its original patents have long expired, allowing for the manufacturing and sale of generic versions [7].
Who manufactures generic griseofulvin?
Numerous pharmaceutical companies produce generic versions of griseofulvin. These manufacturers include but are not limited to Teva Pharmaceuticals, Aurobindo Pharma, and Mylan Pharmaceuticals [8]. The availability of generic options has made the medication more accessible [7].
How does griseofulvin compare to other antifungal medications?
Griseofulvin is effective against dermatophytes but has limited activity against other types of fungi like yeasts and molds [2]. For yeast infections, such as Candida, other antifungals like fluconazole or clotrimazole are typically used. For more severe or widespread dermatophyte infections, or those involving deeper tissues, systemic azoles (like itraconazole or terbinafine) might be considered [9]. Terbinafine is often a preferred treatment for onychomycosis due to its efficacy and shorter treatment duration compared to griseofulvin [9].
What are the drug interactions to be aware of with griseofulvin?
Griseofulvin can interact with several medications. It may decrease the effectiveness of anticoagulants (like warfarin) and oral contraceptives [6]. It can also affect the metabolism of drugs like cyclosporine and barbiturates [6]. Patients should inform their healthcare providers about all medications they are taking before starting griseofulvin treatment [6].
Sources:
[1] https://www.ncbi.nlm.nih.gov/books/NBK544116/
[2] https://www.nhs.uk/medicines/griseofulvin/
[3] https://www.sciencedirect.com/topics/pharmacology-and-toxicology/griseofulvin
[4] https://www.drugs.com/griseofulvin.html
[5] https://www.webmd.com/drugs/2/drug-4105/griseofulvin-oral/details
[6] https://www.mayoclinic.org/drugs-supplements/griseofulvin-oral-route/proper-use/drh-20072891
[7] https://www.drugpatentwatch.com/
[8] https://www.goodrx.com/griseofulvin
[9] https://www.aad.org/public/diseases/a-z/fungal-infections-treatment