New Antifungals, New Solutions

0 Comments | Family Practice News, Feb 15, 2000 | by Sharon Worcester

NAPLES, FLA. -- When it comes to treating tinea versicolor, ketoconazole is the cheapest and safest treatment option, Dr. Theodore Rosen said at the annual meeting of the Florida Society of Dermatology.

Two hours after administering a 400-mg dose of the oral antifungal agent, have the patient sweat it out, he advised.

"Why? Because the drug is secreted in sweat in astronomical concentrations and it will deposit on the skin quite efficiently," said Dr. Rosen, professor of dermatology at Baylor College of Medicine, Houston.

Use it once and this regimen results in a 70% cure rate. Use it again 1 month later and the cure rate jumps to 90%--all for about $18 in Dr. Rosen's experience.

Other options for treating tinea versicolor can be effective but are much more expensive. One option is fluconazole in a dose between 100 and 600 mg. The usual dose is a single 600-mg dose that costs about $60. Itraconazole can also be given in a dose of 200 mg/day for 7 days, or 100 mg/day for 14 days at a cost of about $70.

Terbinafine solution (Lamisil) is an effective topical agent with about a 70% cure rate. It must be used twice daily for 7 days, which takes about two bottles at $58 each.

For treating other fungal infections, Dr. Rosen recommended the following:

* Tinea Pedis. Treatment options include fluconazole, itraconazole, and terbinafine, all of which work well.

Fluconazole should be given in a 150-mg dose for 6 weeks. Itraconazole should be given in a dose of 400 mg/day for 7 days. The higher dose is necessary because the drug is secreted in part through the sebaceous glands, and there are no Sebaceous glands on the pedal surface, Dr. Rosen noted.

Terbinafine can be used at 250 mg/day for 14 days.

An important thing to remember in treating tinea pedis is the frequency of concomitant onychomycosis.

* Onychomycosis. This condition occurs in up to 10% of the population and is more common in diabetics, the elderly, and immunocompromised patients.

Treatment of onychomycosis is important because untreated onychomycosis can lead to more serious diseases, such as cellulitis. This is especially likely in diabetic patients and patients with fissures and cracks in the skin. It can also increase the risk of thrombophlebitis in the elderly because they may not walk due to pain associated with the infection. Fungal sepsis can occur in immunosuppressed patients.

Good drugs for treatment of onychomycosis include fluconazole, itraconazole, and terbinafine.

Fluconazole should be given as 300 mg once weekly. Treatment takes about 4 months for fingernails and 9-12 months for toenails. Itraconazole costs about half as much and works in about half the time.

Terbinafine works best when used daily because relapse is common when the drug is pulsed, Dr. Rosen said. The cost is slightly more than for itraconazole, but it also works in less time than fluconazole.

It is important to remember that in southern Gulf Coast states like Florida and Texas, about 15% of cases are caused by nondermatophytes, which don't respond to terbinafine. Itraconazole should be used for those cases.

"I tell patients that two-thirds to three-fourths of them will be happy when I'm done," Dr. Rosen said, noting that the remaining patients either don't absorb the drug, don't take the drug, or don't have onychomycosis. Also, some organisms are inherently resistant.

The most serious cases, like those with a "god-awful thick nail standing up at a 65-degree angle," require avulsion so the nail area can be sterilized, he said.

* Tinea Cruris and Tinea Corporis. Fluconazole is given as 150 mg/week in one dose for 4 weeks. Itraconazole can be used at 200 mg/day for 7 days, and terbinafine can be used at 250 mg/day for 7-14 days. All work well, Dr. Rosen said.

Itraconazole has been used successfully in children at a dose of 5 mg/kg per day for 7 days.

If an animal is the source of the infection, the animal must be treated. An effective and inexpensive shampoo is Sulfodex, which can be found for less than $4 in pet stores. The shampoo generally works as well as much more expensive products prescribed by veterinarians, he said.

* Tinea Capitis. Studies on treatment of this infection are the most difficult to interpret, because most have been done outside the United States and involve organisms not often seen in this country.

Based on the small studies that are available in the United States, griseofulvin remains the preferred treatment, but many physicians are finding that it works less and less often, Dr. Rosen said.

Other options include itraconazole at 5 mg/kg per day for 30 days, fluconazole at 6mg/kg per day for 20-30 days, and terbinafine at 6 mg/kg per day for 30 days.

For children, capsules can be broken apart and served in applesauce. This is preferred over use of the itraconazole solution, because the base for the solution can cause diarrhea, he noted.