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Pharmacologic class: Synthetic allylamine derivative
Therapeutic class: Antifungal
Pregnancy risk category B
Unclear. Thought to interfere with sterol biosynthesis of fungal cell membrane permeability by inhibiting enzymes responsible for normal fungal growth and maturation, resulting in cell death.
Gel (topical): 1%
Oral granules: 125 mg, 187.5 mg
Solution (topical): 1%
Spray (topical): 1%
Tablets: 250 mg
Indications and dosages
➣ Tinea cruris; tinea corporis; tinea pedis; tinea versicolor
Adults and children ages 12 and older: Massage cream into affected area and surrounding area once or twice daily for 7 to 14 days, not to exceed 4 weeks. Or, for tinea pedis, apply gel to affected area once daily at bedtime for 1 week. Or, for tinea cruris and tinea corporis, spray or apply gel to affected area once daily (morning or night) for 1 week. Or, for tinea pedis, spray between toes b.i.d. (morning and night) for 1 week.
➣ Onychomycosis of fingernail or toenail
Adults: For fingernail infection, 250 mg P.O. daily for 6 weeks. For toenail infection, 250 mg P.O. daily for 12 weeks.
➣ Tinea capitis
Children ages 4 and older weighing less than 25 kg (55 lb): 125 mg P.O. daily for 6 weeks
Children ages 4 and older weighing 25 to 35 kg (55 to 77 lb): 187.5 mg P.O. daily for 6 weeks
Children ages 4 and older weighing more than 35 kg (77 lb): 250 mg P.O. daily for 6 weeks
• Hypersensitivity to drug or its components
• Chronic active hepatic disease
Use cautiously in:
• renal impairment (use not recommended)
• pregnant or breastfeeding patients (use not recommended)
• children younger than age 12 (safety and efficacy not established with cream, spray, or tablet use).
• Give with or without food, but not with coffee, cola, or tea.
• Know that oral granules should be sprinkled on nonacidic food, such as pudding or mashed potatoes. Fruit-based food such as applesauce shouldn't be used.
• Know that oral granules should be swallowed without being chewed.
• Don't put occlusive dressing over affected area after cream application.
CNS: headache, depression
EENT: visual disturbances
GI: nausea, diarrhea, dyspepsia, abdominal pain, flatulence
Hepatic: hepatic failure
Skin: burning, stinging, dryness, itching, and local irritation (with topical form); rash; pruritus; urticaria; erythema multiforme; Stevens-Johnson syndrome
Other: taste and smell disturbances
Drug-drug. Cimetidine: decreased terbinafine clearance
Cyclosporine: increased cyclosporine clearance
Dextromethorphan: increased dextromethorphan blood level
Rifampin: increased terbinafine clearance
Warfarin: altered warfarin efficacy
Drug-diagnostic tests. Hepatic enzymes: increased levels
Neutrophils: decreased count
Drug-food. Caffeine-containing foods and beverages: decreased caffeine clearance
Drug-herbs. Chaparral, comfrey, germander, jin bu huan, kava, pennyroyal: increased risk of hepatotoxicity
Cola nut, guarana, yerba maté: decreased clearance of these herbs
• Monitor CBC and liver function tests.
Watch for signs and symptoms of erythema multiforme. Report early indications before they progress to Stevens-Johnson syndrome.
• Tell patient he may take with or without food.
• Advise caregiver that oral granules should be sprinkled on nonacidic food, such as pudding or mashed potatoes and not to use fruit-based food such as applesauce.
• Advise caregiver that oral granules should be swallowed without being chewed.
• Instruct patient to avoid coffee, tea, and colas, which can worsen adverse drug reactions.
• Tell patient drug may take 4 weeks to be effective in fingernail infections and 10 weeks in toenail infections. Urge him to keep taking it even though symptoms don't improve right away.
Advise patient to immediately report rash, sore throat, cough, fever, or yellowing of skin or eyes.
• Instruct patient how to use topical drug, to wash affected area with soap and water and dry area completely before applying drug, and to wash hands after each use.
• Instruct patient not to place occlusive dressing over affected area after applying cream.
• Advise patient to wear well-fitting, ventilated shoes and to change shoes and socks at least once daily when receiving treatment for athlete's foot.
• Caution patient not to let topical drug contact eyes, nose, or mouth.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, foods, and herbs mentioned above.