Prescription medication · Allylamine Antifungal
terbinafine
Also sold as Lamisil. Terbinafine treats onychomycosis, a fungal infection of the toenails or fingernails.
Data updated 2026-05-15
- 6,848
- FDA reportsLightly reported
- 17
- InteractionsSeveral interactions
- $0.28
- Generic price (NADAC)
What the data shows
terbinafine (Lamisil) is a prescription Allylamine Antifungal, reported less often than most tracked drugs (6,848 FDA reports), with 17 documented drug interactions.
Reporting volume reflects how widely a drug is used and studied, not how dangerous it is, a FAERS report documents a temporal association, never proof of cause.
terbinafine (Lamisil) is a prescription Allylamine Antifungal. Terbinafine treats onychomycosis, a fungal infection of the toenails or fingernails.
Terbinafine is an antifungal medicine. It is used to treat fungal infections of the fingernails and toenails.
Verify with FDA → · CMS NADAC pricing →
Drug Pricing (NADAC)
Generic Price
$0.28/unit
Generic Available
Yes (8 manufacturers)
Pricing data from NADAC (CMS), effective December 18, 2024. Compare all drug costs →
What it does
Terbinafine treats onychomycosis, a fungal infection of the toenails or fingernails.
Common side effects
Headache, Diarrhea, Rash
Key warnings
Terbinafine can cause liver problems, including liver failure.
The sections below are summarized in plain English from terbinafine's FDA-approved prescribing information. They describe what the official label says, and are not personal medical advice.
How It Works
Terbinafine belongs to a class of medicines called allylamine antifungals. It works by stopping the growth of fungi. This eventually kills the fungus causing the infection.
Side Effects (from patient reports)
Based on 6,848 FDA adverse event reports.
Most-reported reactions
Adverse reactions in FAERS for terbinafine, by number of reports
- Rash
Rash
391 reports
- Pruritus
Pruritus
316 reports
- Fatigue
Fatigue
300 reports
- Nausea
Nausea
280 reports
- Ageusia
Ageusia
270 reports
- Pain
Pain
267 reports
- Headache
Headache
229 reports
- Drug Interaction
Drug Interaction
224 reports
- Diarrhoea
Diarrhoea
217 reports
- Malaise
Malaise
217 reports
What this shows Bars show how often each reaction was reported, not how likely it is to happen, a report records a temporal association, never proof that the drug caused it.
Reports over time
Adverse-event reports filed for terbinafine each year to the FDA Adverse Event Reporting System (FAERS).
Year-to-year volume tracks usage, prescribing, and scrutiny, not a change in per-patient risk. Source: FDA FAERS.
Where terbinafine sits
terbinafine has more FDA adverse-event reports than 30% of the drugs FAERS tracks. A high position reflects how widely a drug is used and watched, not how dangerous it is.
Percentile across all drugs PlainMeds tracks by FAERS report volume. The dot is terbinafine; the line is the median (50th percentile).
FDA Adverse Event Report Analysis
Detailed analysis of 6,848 reports from the FDA Adverse Event Reporting System (FAERS). Reports span 2003–2025.
Total Reports
6,848
Reports Mentioning Death
428
6.3% of reports — not proof of cause
Hospitalization Reports
1,849
Top Indication
Product Used For Unknown Indication
Gender Distribution
Age Distribution
Most Reported Adverse Reactions (FAERS)
| # | Reaction | Reports |
|---|---|---|
| 2 | RASH | 391 |
| 3 | PRURITUS | 316 |
| 4 | FATIGUE | 300 |
| 5 | NAUSEA | 280 |
| 6 | AGEUSIA | 270 |
| 7 | PAIN | 267 |
| 9 | HEADACHE | 229 |
| 10 | DRUG INTERACTION | 224 |
| 11 | DIARRHOEA | 217 |
| 12 | MALAISE | 217 |
| 13 | DRUG RESISTANCE | 196 |
| 14 | ANXIETY | 194 |
| 15 | CHRONIC KIDNEY DISEASE | 194 |
| 16 | DYSPNOEA | 190 |
| 18 | DIZZINESS | 181 |
Reactions in Death Reports
Reactions in Hospitalization Reports
Source: FDA FAERS (Adverse Event Reporting System) Reports are voluntary and do not establish causation
Serious Warnings
Terbinafine can cause liver problems, including liver failure. Your doctor should check your liver before you start taking it and regularly while you are taking it. Tell your doctor right away if you have nausea, loss of appetite, tiredness, vomiting, pain in your upper right belly area, yellowing of the skin or eyes, dark urine, or pale stools. If you have taste changes, stop taking terbinafine. These changes can be severe, long-lasting, or even permanent. Tell your doctor if you feel depressed or have other mood changes.
Known Drug Interactions
Tamsulosin hydrochloride capsules should be used with caution in combination with moderate inhibitors of CYP3A4 (e.g., erythromycin), in combination with strong (e.g., paroxetine) or moderate (e.g., terbinafine) inhibitors of CYP2D6, or in patients known to be CYP2D6 poor metabolizers, particularly at a dose higher than 0.4 mg (e.g., 0.8 mg). The effects of concomitant administration of a moderate CYP2D6 inhibitor (e.g., terbinafine) on the pharmacokinetics of tamsulosin hydrochloride have not been evaluated [see Warnings and Precautions (5.2) and Clinical Pharmacology (12.3)].
Mechanism: Terbinafine slows down the body's ability to break down tamsulosin by blocking a specific liver enzyme. This can lead to higher levels of tamsulosin in your blood.
Based on this finding, it is likely that other inhibitors of both CYP2C9 and CYP3A4 (e.g., ketoconazole, amiodarone) may also lead to a substantial increase in the systemic exposure (C max and AUC) of terbinafine when concomitantly administered.
Mechanism: Ketoconazole stops the body from breaking down terbinafine, which can lead to much higher levels of terbinafine in your blood.
Drug interactions have also been noted with cimetidine, fluconazole, cyclosporine, rifampin, and caffeine. The influence of terbinafine on the pharmacokinetics of fluconazole, cotrimoxazole (trimethoprim and sulfamethoxazole), zidovudine or theophylline was not considered to be clinically significant. Coadministration of a single dose of fluconazole (100 mg) with a single dose of terbinafine resulted in a 52% and 69% increase in terbinafine C max and AUC, respectively.
Mechanism: Fluconazole interferes with the way the body processes terbinafine, leading to higher amounts of terbinafine in the bloodstream.
Drug interactions have also been noted with cimetidine, fluconazole, cyclosporine, rifampin, and caffeine. In vitro studies with human liver microsomes showed that terbinafine does not inhibit the metabolism of tolbutamide, ethinylestradiol, ethoxycoumarin, cyclosporine, cisapride and fluvastatin. Terbinafine increases the clearance of cyclosporine by 15%.
Mechanism: Terbinafine makes the body get rid of cyclosporine more quickly than normal.
The influence of terbinafine on the pharmacokinetics of fluconazole, cotrimoxazole (trimethoprim and sulfamethoxazole), zidovudine or theophylline was not considered to be clinically significant.
Mechanism: Terbinafine does not significantly change how the body handles trimethoprim.
This is a plain-language summary of FDA-label interaction records and does not provide individual medication-combination directions.
Common Questions
Can I drink alcohol while taking terbinafine?
How long does it take for terbinafine to work?
What should I do if I get a rash while taking terbinafine?
Can terbinafine interact with other medicines I am taking?
What if I have kidney problems?
Will terbinafine cause my hair to fall out?
Can terbinafine cause depression?
Is there a generic version of terbinafine?
What do the tablets look like?
What if I have an allergic reaction?
What are the common side effects of terbinafine?
Does terbinafine interact with other medications?
What drug class is terbinafine?
What pregnancy or breastfeeding source fields are listed for terbinafine?
Related Medications in Allylamine Antifungal
Other drugs grouped near terbinafine - same-class peers and common alternatives.
acyclovir
Zovirax
Acyclovir is an antiviral medicine.
Compare with terbinafine →
albendazole
Albenza
Albendazole is a medicine that fights parasites.
Compare with terbinafine →
amphotericin B
Ambisome, Fungizone
Amphotericin B liposome is an antifungal medicine.
Compare with terbinafine →
anidulafungin
Eraxis
Eraxis is an antifungal medicine.
Compare with terbinafine →
atovaquone/proguanil
Malarone
Malarone is a drug used to prevent and treat malaria.
Compare with terbinafine →
Compare beyond drug class
Nationwide peers by FAERS volume & death-report share
Two PlainMeds-derived comparison paths for terbinafine: nearest FDA FAERS report volume and nearest death-report share among drugs with at least 1,000 logged reports, excluding same-class neighbors listed above. Counts reflect reporting volume, not proven individual harm.
Similar FAERS report volume
Nearest drugs by total FAERS reports. This record: 6,848.
Similar death-report share
Nearest drugs by FAERS death-report share. This record: 6.25%.
- perampanel Δ 0.05 pts · 7,188 reports · Anticonvulsant (AMPA Antagonist) 6.30%death share
- indapamide Δ 0.09 pts · 17,199 reports · Thiazide-Like Diuretic 6.34%death share
- meloxicam Δ 0.09 pts · 55,835 reports · Nonsteroidal Anti-Inflammatory Drug (NSAID) 6.34%death share
- nitrofurantoin Δ 0.10 pts · 15,757 reports · Nitrofuran Antibiotic 6.35%death share
Medication Guides
Understanding Drug Interactions
How CYP450 enzymes, inhibitors, and inducers affect your medications
Generic vs Brand Name Drugs
FDA requirements, cost savings, and when the difference matters
Narrow Therapeutic Index Drugs
FDA bioequivalence and label-record context for narrow therapeutic index medicines
Common Drug Interactions
Dangerous medication combinations and how to protect yourself
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What the FDA Data Shows for terbinafine
The FDA label for terbinafine (sold under brand names such as Lamisil) classifies it as a prescription-only medication in the Allylamine Antifungal class. Terbinafine treats onychomycosis, a fungal infection of the toenails or fingernails. Official labeling lists 10 commonly reported side effects, including Headache, Diarrhea, Rash.
Post-market surveillance from the FDA Adverse Event Reporting System (FAERS) captures real-world experience. For this drug, FAERS contains 6,848 voluntary reports. The database also lists 17 documented drug interactions derived from FDA labeling, with the top-flagged interaction rated moderate severity. NADAC pricing from CMS shows a generic unit cost of $0.28.
Report counts do not establish causation, a FAERS entry documents a temporal association, not proof that the drug produced the outcome. Widely prescribed medications naturally accumulate more reports than niche therapies, so raw totals must be interpreted alongside total exposure. Shortage status, recall history, and patent information are separate source-record fields. This page is a public FDA/CMS registry and does not provide medical, treatment, substitution, or medication-change directions.
Data Sources
Drug labeling: FDA Drug Labels (SPL/DailyMed). Adverse events: FDA Adverse Event Reporting System (FAERS). Pricing: CMS National Average Drug Acquisition Cost (NADAC).
FAERS reports are voluntary and do not establish causation. Drug interactions are derived from FDA labeling and clinical references. This registry does not provide medication decisions.
Last updated: September 30, 2025
PlainMeds is rendered directly from FDA openFDA/FAERS extracts, DailyMed labels, and CMS drug-pricing files, no number is typed in by an editor. FAERS counts, recalls, shortages, and price figures on this page are queried live from those federal extracts. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 2026-05-15. Primary sources: openFDA / FAERS, DailyMed and CMS Part B ASP.
Read our methodology - how this data is sourced, computed, and verified.
Data currency: FDA FAERS adverse-event reports through 2025, CMS NADAC acquisition-cost pricing effective December 2024, compiled from the source snapshot dated . See our methodology for per-source dates and refresh cadence. Spot a figure that looks wrong? Report a data issue.
All federal data sources used on this page
- FDA Orange Book - approved drug products with therapeutic equivalence. accessdata.fda.gov/cder/ob
- FDA DailyMed - NIH-hosted drug labeling for FDA-approved meds. dailymed.nlm.nih.gov
- FDA Adverse Event Reporting System (FAERS) - post-marketing safety surveillance. fda.gov/drugs/faers
- NLM RxNorm - standardized clinical drug nomenclature. nlm.nih.gov/research/umls/rxnorm
- CMS Medicare Part B Drug Average Sales Price Files - federal drug pricing data. cms.gov/medicare/part-b-drugs/asp
- FDA Drug Shortages Database - current and resolved drug shortage tracking. accessdata.fda.gov/drugshortages