Clotrimazole works by inhibiting the growth of individual Candida or fungal cells by altering the permeability of the fungal cell wall. It binds to phospholipids in the cell membrane and inhibits the biosynthesis of ergosterol and other sterols required for cell membrane production. Clotrimazole may be fungistatic (slow fungal growth) or fungicidal (result in fungal cell death).
It is commonly available without a prescription in various dosage forms, such as a cream, vaginal tablet, or as a prescription troche or throat lozenge (prescription only). Topically, clotrimazole is used for vulvovaginal candidiasis (yeast infection) or yeast infections of the skin. For vulvovaginal candidiasis (yeast infection), clotrimazole tablets and creams are inserted into the vagina. Troche or throat lozenge preparations are used for oropharyngeal candidiasis (oral thrush) or prophylaxis against oral thrush in neutropenic patients.
Clotrimazole is usually used 5 times daily for 14 days for oral thrush, twice daily for 2 to 8 weeks for skin infections, and once daily for 3 or 7 days for vaginal infections.
Clotrimazole may be compounded with a glucocorticoid, such as betamethasone, in a topical cream for the treatment of tinea corporis (ringworm), tinea cruris (jock itch) and tinea pedis (athlete's foot). Although FDA approved, clotrimazole-betamethasone combination cream is not the preferred treatment for dermatophyte infections due to increased side effects from the topical glucocorticoid. Although temporary relief and partial suppression of symptoms may be observed with the combination therapy, glucocorticoids can elicit an immunosuppressive response and rebound effect that results in more severe infection typically requiring systemic antifungal agents to treat the disease. Combination creams are best avoided in order to improve treatment outcome, reduce the possibility of skin atrophy associated with prolonged topical glucocorticoid use, and to limit the cost of treatment. It can be effective in treating chronic paronychia. The preferred treatment of tinea infections is therefore with clotrimazole monotherapy.
Topical and oral clotrimazole can be used in both adults and children.
Additionally, clotrimazole may be used to treat the sickling of cells (related to sickle cell anemia).
Abnormal liver function tests have been reported in patients treated with clotrimazole troches; elevated SGOT levels were reported in about 15% of patients in the clinical trials.
Nausea, vomiting, unpleasant mouth sensations and pruritus have also been reported with the use of the troche.
Mycelex® Troches are administered only as a lozenge that must be slowly dissolved in the mouth. The recommended dose is one troche five times a day for fourteen consecutive days. Only limited data are available on the safety and effectiveness of the clotrimazole troche after prolonged administration; therefore, therapy should be limited to short term use, if possible.
For prophylaxis to reduce the incidence of oropharyngeal candidiasis in patients immunocompromised by conditions that include chemotherapy, radiotherapy, or steroid therapy utilized in the treatment of leukemia, solid tumors, or renal transplantation, the recommended dose is one troche three times daily for the duration of chemotherapy or until steroids are reduced to maintenance levels.
There are no known drug interactions with topical clotrimazole.
You should tell your doctor about all prescription, non-prescription, illegal, recreational, herbal, nutritional, or dietary drugs you are taking.
Mycelex® Troches, white discoid, uncoated tablets are supplied in bottles of 70 and 140. Mycelex® Troches are also available for institutional use in foil packages of 70 tablets.
Mycelex® Troches are not indicated for the treatment of systemic mycoses including systemic candidiasis.
Abnormal liver function tests have been reported in patients treated with clotrimazole troches; elevated SGOT levels were reported in about 15% of patients in the clinical trials. In most cases the elevations were minimal and it was often impossible to distinguish effects of clotrimazole from those of other therapy and the underlying disease (malignancy in most cases). Periodic assessment of hepatic function is advisable particularly in patients with pre-existing hepatic impairment.
Since patients must be instructed to allow each troche to dissolve slowly in the mouth in order to achieve maximum effect of the medication, they must be of such an age and physical and/or mental condition to comprehend such instructions.
An 18 month dosing study with clotrimazole in rats has not revealed any carcinogenic effect.
Usage in Pregnancy
Pregnancy Category C: Clotrimazole has been shown to be embryotoxic in rats and mice when given in doses 100 times the adult human dose (in mg/kg), possibly secondary to maternal toxicity. The drug was not teratogenic in mice, rabbits, and rats when given in doses up to 200, 180, and 100 times the human dose.
Clotrimazole given orally to mice from nine weeks before mating through weaning at a dose 120 times the human dose was associated with impairment of mating, decreased number of viable young, and decreased survival to weaning. No effects were observed at 60 times the human dose. When the drug was given to rats during a similar time period at 50 times the human dose, there was a slight decrease in the number of pups per litter and decreased pup viability.
There are no adequate and well controlled studies in pregnant women. Clotrimazole troches should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
Safety and effectiveness of clotrimazole in children below the age of 3 years have not been established; therefore, its use in such patients is not recommended.
The safety and efficacy of the prophylactic use of clotrimazole troches in children have not been established.
Clinical studies of clotrimazole did not include sufficient numbers of subjects aged 65 and over to determine whether they responsd differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients.