Is terbinafine (antifungal medication) a suitable treatment option for a diabetic patient with a fungal skin infection?

Terbinafine for Fungal Skin Infections in Diabetic Patients

Terbinafine is the preferred treatment for fungal skin infections in diabetic patients due to its fungicidal action and lower risk of drug interactions. 1

Treatment Recommendations

Oral Terbinafine

• Dosage: 250mg once daily 1, 2
• Duration:
  • 1-2 weeks for skin infections 1
  • 12 weeks for toenail infections 1, 2
  • 6 weeks for fingernail infections 2
• Efficacy: 73% mycological cure rate in diabetic patients 1

Pre-Treatment Assessment

• Baseline liver function tests are mandatory before initiating therapy, especially in patients with history of alcohol consumption 1
• Laboratory confirmation of fungal infection is essential before starting treatment 1

Monitoring

• Monitor for potential side effects:
  • Liver problems (persistent nausea, anorexia, fatigue, vomiting, right upper abdominal pain, jaundice, dark urine, pale stools) 2
  • Taste or smell disturbances 2
  • Skin reactions (hives, mouth sores, blistering) 2
  • Depressive symptoms 2

Evidence Supporting Use in Diabetic Patients

Terbinafine has demonstrated comparable efficacy in diabetic patients as in non-diabetic populations, with mycological cure rates of 62-78% 3. This is particularly important as diabetic patients are at higher risk for fungal infections and complications from these infections.

The British guideline society specifically recommends oral terbinafine as the preferred treatment for fungal skin infections in diabetic patients 1. This recommendation is based on:

1. Its fungicidal (rather than fungistatic) action
2. Lower risk of drug interactions compared to alternatives like itraconazole
3. Good absorption into skin, hair, and nails 4

Prevention Strategies for Diabetic Patients

To prevent recurrence and complications, advise patients to:

• Keep nails short and clean
• Thoroughly dry between toes after bathing
• Wear cotton, absorbent socks and change daily
• Apply antifungal powders to shoes and feet
• Avoid sharing nail clippers
• Wear protective footwear in public areas 1

Potential Pitfalls

1. Concurrent corticosteroid use: Avoid using triamcinolone or other corticosteroids with terbinafine as this may reduce efficacy and worsen infection 1

2. Inadequate treatment duration: Ensure complete treatment course is followed; premature discontinuation can lead to treatment failure 1

3. Drug interactions: While terbinafine has fewer interactions than some alternatives, monitor patients taking medications for depression, high blood pressure, or heart problems 2

4. Liver toxicity: Patients should be monitored for signs of liver problems during treatment 2

5. Recurrence: Onychomycosis has high recurrence rates (40-70%) even with established treatments, highlighting the need for long-term preventive strategies 1

Alternative Options

For diabetic patients who cannot tolerate oral terbinafine, topical options may be considered for mild-to-moderate infections:

• Amorolfine 5% nail lacquer (50% efficacy in distal nail infections)
• Ciclopirox 8% lacquer (34% mycological cure rate)
• Efinaconazole 10% solution (50% mycological cure rate) 1

However, these topical treatments are generally less effective than oral terbinafine, particularly for nail infections.