Examples

Allylamines

Azoles

Other oral antifungals

All of these medicines are by prescription only. Allylamines and azoles are classes of drugs. Their effectiveness and side effects may vary.

Terbinafine tablets are taken once a day for 6 weeks for fungal fingernail infections, and for 12 weeks or longer for fungal toenail infections. Terbinafine tablets can be used according to a pulse dosing schedule. Pulse dosing refers to taking medicine daily for 1 week a month for 2, 3, or 4 months. Some people find it easier to stay with this medicine schedule, and the treatment is likely to be cheaper.

Oral azoles (tablets or capsules) are taken daily for 3 to 18 months, depending on the medicine. Oral azoles can be used according to a weekly pulse dosing schedule. Pulse dosing refers to taking medicine daily for 1 week a month for 2, 3, or 4 months. Some people find it easier to stay with this medicine schedule, and the treatment is likely to be cheaper.

Griseofulvin is taken twice a day until nails are clear of infection. For infections in the fingernails, griseofulvin may be taken for 6 to 8 months. For infections in toenails, griseofulvin may be taken for 12 to 18 months to cure an infection and to prevent reinfection.

How It Works

Allylamines and azoles kill fungi. Griseofulvin prevents the growth of fungi. Killing fungi does not guarantee a normal-looking nail.

Why It Is Used

Oral antifungal medicines are used to treat fungal nail infections. Often the medicine used depends on the type of infection you have.

• Terbinafine is a medicine for fungal nail infections caused by dermatophytes, including distal subungual onychomycosis and white superficial onychomycosis. Most fungal nail infections are caused by this type of fungus. Terbinafine may also be effective against some molds (nondermatophytes).
• Itraconazole is a medicine for infections caused by molds and yeast (Candida). It can also be used for dermatophytes.
• Fluconazole is a medicine for Candida infections and can also be used against dermatophytes. It may be used if you are taking a lot of other medicines.
• Griseofulvin is more effective against fingernail infections than toenail infections and is rarely used for toenail infections. It is only effective against infections caused by dermatophytes. It is the only antifungal currently approved by the U.S. Food and Drug Administration (FDA) for fungal nail infections in children.

How Well It Works

Oral antifungals may cure fungal nail infections. Most research has been on using these medicines for toenail infections.

Oral antifungals to treat fungal nail infections include terbinafine (Lamisil) and itraconazole (Sporanox). Studies comparing these two medicines found that terbinafine cured the infection in 55% of people and itraconazole cured the infection in 26% of people after 16 weeks of treatment.¹

Fluconazole (Diflucan), ketoconazole (Nizoral), and griseofulvin (Grifulvin V) are used less often. Fluconazole seems to help, but not as much as terbinafine or itraconazole.¹ And ketoconazole and griseofulvin may work, but there is not enough evidence from studies to say just how well they work.³

Oral antifungal medicines often kill fungi but do not immediately improve the appearance of the nail.

Side Effects

Oral antifungals have both minor and dangerous side effects.

Minor side effects include:

• Headaches.
• Stomach upset.
• Skin rashes.
• Changes in taste sensation (rare, and with terbinafine only).
• Visual disturbances (rare, and with terbinafine only).
• Increased sensitivity of skin to sunlight (photosensitivity—with griseofulvin only).

Dangerous side effects of oral antifungals include:²

• Drug interactions. Commonly prescribed medicines can increase or decrease terbinafine or azole levels in your body. Also, other medicines can build up in the your blood when taken with terbinafine or an azole. Before you take oral antifungal medicines, let your doctor know what other medicines you are taking.
• Liver damage or failure, requiring a liver transplant. A small number of deaths after liver failure have been linked to terbinafine and azoles. Warning signs of liver failure include:
  • Nausea, vomiting, belly pain.
  • Fatigue.
  • Loss of appetite.
  • Dark urine.
  • Changes in skin color.

Itraconazole may cause heart failure. Warning signs of heart failure include:

• Shortness of breath at rest, with mild exertion, or when lying flat.
• Severe swelling of feet, ankles, legs, or abdomen.
• Weight gain.
• Fatigue.
• Coughing up white or pink mucus.
• Faster-than-usual heart rate.

During oral antifungal treatment, your doctor may require blood tests to check your kidney and liver function.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

Terbinafine and azoles pass into breast milk. It is not known whether they harm a fetus. It is not known whether griseofulvin passes into breast milk. If you are pregnant, could become pregnant, or are breast-feeding, talk to your doctor before you take oral antifungal medicines.

Advanced age lowers your chances for a cure. This may be due to slowed nail growth and, in some people, poor blood circulation to the feet.

Griseofulvin was one of the first oral antifungal medicines. But it does not provide a long-term cure, has serious side effects, and requires a long treatment time (12 to 18 months). The newer oral antifungals are much more effective, relatively safe for healthy people, and don't take as long to work.

Oral azoles are best absorbed into the body when taken with cola, orange juice, or food. Some medicines may reduce your body's absorption of azole medicine. These include cimetidine (Tagamet), stomach acid neutralizers, and rifampin (Rifadin).

Griseofulvin should be taken with fatty foods for better absorption into the body.

In some people, a fungal infection comes back after treatment. This is called a recurrence. Recurrence of infection may be a new infection or a regrowth of the original infection that was not eliminated by treatment.

Consider the following about treatment with oral antifungal medicine:

• Oral antifungal medicines are not recommended if you have liver problems.
• Do not drink alcohol while taking these medicines, as this increases your risk of liver damage.
• Itraconazole (Sporanox) is not recommended if you have a history of heart failure.
• Griseofulvin should not be taken if you have lupus or are allergic to penicillin.

For more information on deciding whether to use oral antifungal medicines, see:

Nail Infection: Should I Take Antifungal Pills?

Complete the new medication information form (PDF)(What is a PDF document?) to help you understand this medication.

References

Credits