Can terbinafine (antifungal medication) be discontinued at day 11 in a patient experiencing possible side effects and switched to topical medications for treatment of a fungal infection?

Can Terbinafine Be Discontinued at Day 11 for Side Effects and Switched to Topical Therapy?

Yes, terbinafine should be discontinued immediately at day 11 if the patient is experiencing possible side effects, and the patient should be counseled to report these symptoms to their physician for evaluation and alternative treatment planning. 1

Immediate Discontinuation Criteria

The FDA drug label explicitly instructs patients to discontinue terbinafine and immediately report to their physician if they experience:

• Cutaneous reactions: hives, mouth sores, blistering and peeling of skin, rashes 1, 2
• Gastrointestinal symptoms: persistent nausea, anorexia, fatigue, vomiting, right upper abdominal pain 1
• Hepatic warning signs: jaundice, dark urine, or pale stools 1
• Sensory disturbances: taste or smell disturbances 1
• Psychiatric symptoms: depressive symptoms 1
• Allergic manifestations: swelling of face, lips, tongue, or throat, difficulty swallowing or breathing 1

Severe cutaneous adverse reactions including erythema multiforme, erythroderma, and severe urticaria have been documented and require immediate discontinuation 2. Patients should be counseled about discontinuing terbinafine at the onset of any cutaneous eruption 2.

Safety Profile Context

Only 0.8% of patients require discontinuation of terbinafine due to side effects in clinical trials, with gastrointestinal disturbances and rashes occurring in less than 8% of patients 3. However, when side effects do occur, they warrant immediate cessation 1, 2.

Adverse effects—mainly gastrointestinal and minor skin rashes—were reported in only 5.3% of patients in post-marketing surveillance, with the drug being generally well tolerated 4. Despite this favorable overall profile, any concerning symptoms should prompt discontinuation 1.

Switching to Topical Therapy

Topical therapy alone is NOT recommended for tinea capitis (scalp infections), as oral therapy is generally indicated to achieve both clinical and mycological cure. 3 However, the appropriateness of switching to topical therapy depends entirely on the infection site:

For Onychomycosis (Nail Infections):

• Topical alternatives include: amorolfine 5% lacquer applied once or twice weekly for 6-12 months, or ciclopirox 8% lacquer applied once daily for up to 48 weeks 5, 6
• These are appropriate alternatives when systemic therapy poses excessive risk 6

For Tinea Capitis (Scalp Infections):

• Topical therapy alone is contraindicated as it cannot achieve clinical and mycological cure 3
• Alternative oral agents must be considered: griseofulvin (particularly for Microsporum species) or itraconazole 3

For Cutaneous Dermatophyte Infections (Tinea Corporis/Cruris/Pedis):

• Topical terbinafine 1% cream applied twice daily has achieved approximately 80-90% efficacy rates 7
• This represents a viable alternative to oral therapy for skin infections 7

Critical Clinical Caveat

At day 11 of treatment, the patient has received insufficient duration for therapeutic effect regardless of the infection type. Standard terbinafine courses require:

• 6 weeks for fingernail onychomycosis 1
• 12 weeks for toenail onychomycosis 1, 8
• 4 weeks for Trichophyton tinea capitis 3
• 2 weeks for cutaneous dermatophyte infections 4

The optimal clinical effect is seen months after cessation due to the time required for outgrowth of healthy nail or resolution of infection 1. Therefore, discontinuation at day 11 means the patient received no therapeutic benefit and requires complete re-initiation of alternative therapy 1.

Management Algorithm

1. Discontinue terbinafine immediately upon recognition of possible side effects 1, 2
2. Evaluate the specific side effect to determine if medical evaluation or emergency care is needed 1
3. Identify the infection site (scalp vs. nail vs. skin) to determine appropriate alternative therapy 3
4. For tinea capitis: Switch to oral griseofulvin or itraconazole; topical therapy is inadequate 3
5. For onychomycosis: Consider topical amorolfine or ciclopirox if systemic therapy is contraindicated, or alternative oral agent (itraconazole, fluconazole) if systemic therapy is still appropriate 5, 6
6. For cutaneous infections: Topical terbinafine 1% cream or other topical antifungals are appropriate alternatives 7