Poor
Needs Revision
Patient Risk:
Moderate
Summary
Several safety/dosing/interaction/indication claims are not supported by the provided label excerpts or cannot be verified from the supplied text (e.g., exact side effects list, specific antifungal efficacy by condition, mechanism details, and generic-manufacturing/patent statements). A few label-supported safety items are present (taste disturbance, liver risk), but overall many claims lack label support or go beyond provided labeling content.
Category Scores
Accurate Statements
Less common but more serious side effects of terbinafine include liver problems.
WARNINGS AND PRECAUTIONS (5.1) and ADVERSE REACTIONS (6.1, 6.2) describe hepatotoxicity including liver failure.
Less common but more serious side effects of terbinafine include severe skin reactions.
ADVERSE REACTIONS (6.2) includes 'Skin and subcutaneous tissue disorders: Serious skin reactions…'
Terbinafine is metabolized by the liver.
Not supported in the supplied excerpts (no metabolism statement present).
Rifampin can decrease terbinafine levels.
DRUG INTERACTIONS (7.1) states terbinafine clearance is increased 100% by rifampin.
Cimetidine can increase terbinafine levels.
DRUG INTERACTIONS (7.1) states terbinafine clearance is decreased 33% by cimetidine.
Unsupported Statements
Terbinafine hydrochloride is an antifungal medication available in 250 mg tablets.
No supporting excerpt provided for tablet strength availability as a statement; supplied text only specifies 'Terbinafine Tablets, USP 250 mg' but does not explicitly confirm this claim.
Terbinafine belongs to the class of drugs called allylamines.
Class designation not present in supplied excerpts.
Terbinafine works by inhibiting the enzyme squalene epoxidase.
Mechanism of action (squalene epoxidase inhibition) not present in supplied excerpts.
Squalene epoxidase is essential for the synthesis of ergosterol in fungi.
Not present in supplied excerpts.
Ergosterol is a key component of the fungal cell membrane.
Not present in supplied excerpts.
By disrupting ergosterol production, terbinafine weakens the fungal cell membrane, leading to cell death.
Not present in supplied excerpts.
Terbinafine’s mechanism is specific to fungal cells, which helps to minimize effects on human cells.
Not present in supplied excerpts.
Terbinafine 250 mg tablets are commonly prescribed for onychomycosis (a fungal infection of the nails).
Label excerpt supports indication for onychomycosis, but 'commonly prescribed' is not stated in the provided label text.
Terbinafine is effective against tinea pedis (athlete's foot).
Provided label excerpt indicates onychomycosis due to dermatophytes; no support for tinea pedis in the supplied text.
Terbinafine is effective against tinea cruris (jock itch).
No support for tinea cruris in the supplied text.
Terbinafine is effective against tinea corporis (ringworm) when severe or not responsive to topical treatments.
No support for tinea corporis or conditional use in the supplied text.
Common side effects of terbinafine tablets include diarrhea.
Label excerpt lists gastrointestinal symptoms including diarrhea among adverse events, but does not label them as 'common' in the supplied excerpts.
Common side effects of terbinafine tablets include indigestion.
Label excerpt includes dyspepsia, but does not state 'common' or map 'indigestion' to 'dyspepsia' explicitly.
Common side effects of terbinafine tablets include abdominal pain.
Label excerpt includes abdominal pain as an adverse event but does not state 'common' in the supplied excerpts.
Common side effects of terbinafine tablets include headaches.
Headaches not included in supplied adverse reaction excerpts.
Common side effects of terbinafine tablets include rash.
Rashes are mentioned, but 'common' is not supported by the supplied excerpts.
Common side effects of terbinafine tablets include changes in taste perception.
Taste disturbance is described, but the supplied excerpt does not classify it as 'common' or use this wording.
Less common but more serious side effects of terbinafine include blood disorders.
Blood disorders are broader than the specific supplied items (e.g., TMA, cytopenias). Supplied excerpt does include pancytopenia/agranulocytosis/thrombocytopenia/anemia, but 'less common' and generalized 'blood disorders' wording is not supported.
For nail infections, terbinafine treatment can last from 6 weeks to 3 months or longer.
Label excerpt provides fingernail 6 weeks and toenail 12 weeks; 'or longer' is not supported.
For skin infections, terbinafine is generally treated for 2 to 4 weeks.
No skin infection dosing is provided in the supplied label excerpts; only onychomycosis dosing is included.
Terbinafine can interact with other medications.
This is general; no label excerpt states this exact claim, though interactions are described. The 'can interact' phrasing is non-specific and not directly supported.
Terbinafine can affect the metabolism of certain antidepressants.
No specific antidepressants are mentioned in supplied excerpts; only CYP2D6 inhibition and generic '2D6-metabolized drug' monitoring language is provided.
Terbinafine can affect the metabolism of beta-blockers.
Beta-blockers are not specifically mentioned in the supplied excerpts.
Patients should inform their doctor about all medications they are taking before starting terbinafine.
No counseling/medication list instruction is included in the supplied excerpts.
The original patents for terbinafine have long expired, allowing for the production of generic versions.
Not present in supplied excerpts.
Multiple pharmaceutical companies manufacture generic terbinafine hydrochloride 250 mg tablets.
Not present in supplied excerpts.
Terbinafine is a potent oral antifungal agent.
Not present in supplied excerpts.
Terbinafine is particularly effective for nail fungus where topical treatments may be less successful.
No label support for comparisons vs topical treatments in the supplied excerpts.
Contradictions
Low
AI Statement
Terbinafine is effective against tinea pedis (athlete's foot).
Label Reference
INDICATIONS AND USAGE only supports onychomycosis due to dermatophytes; no tinea pedis indication in supplied excerpts.
Low
AI Statement
Terbinafine is effective against tinea cruris (jock itch).
Label Reference
INDICATIONS AND USAGE only supports onychomycosis due to dermatophytes; no tinea cruris indication in supplied excerpts.
Low
AI Statement
Terbinafine is effective against tinea corporis (ringworm) when severe or not responsive to topical treatments.
Label Reference
INDICATIONS AND USAGE only supports onychomycosis due to dermatophytes; no tinea corporis indication in supplied excerpts.
Important Omissions
No statement about onychomycosis requires confirming diagnosis with nail specimens/lab testing (KOH, culture, or biopsy) prior to initiating terbinafine.
Importance:
Moderate
No mention that terbinafine tablets are contraindicated in chronic or active liver disease and require baseline liver function testing/periodic monitoring and discontinuation if liver injury occurs.
Importance:
Moderate
Taste disturbance guidance is incomplete/omitted: label advises discontinuation if taste disturbance occurs; also includes smell disturbance and depressive symptoms monitoring/instructions to report.
Importance:
Moderate
Safety Assessment
Potential Patient Risk:
Moderate
Several safety-relevant label elements (contraindication/liver monitoring; discontinue for taste/smell disturbance; attention to depressive symptoms; TMA warning) are not conveyed, while some non-labeled efficacy claims (tinea indications/dosing for skin infections) could lead to inaccurate use based on label excerpts provided.
Regulatory Assessment
| On Label |
No |
| Off-label Discussion |
Yes |
| Promotes Unapproved Use |
Yes |
| Hallucination Risk |
Medium |
Recommendation
Needs Revision
Primary Issue
Many claims are not supported by the supplied prescribing information excerpts, including non-onychomycosis (tinea) efficacy and skin-infection dosing; multiple mechanism and class statements are absent from the provided label content.
Suggested Improvement
Limit claims to the provided label-supported indication (onychomycosis), dosing durations for fingernails/toenails, label-supported adverse reactions/warnings (hepatotoxicity, taste/smell disturbance with discontinuation, depressive symptoms, TMA), and interaction specifics (CYP2D6 inhibition; rifampin increases clearance; cimetidine decreases clearance), and remove unsupported patent/manufacturer/general 'common' frequency assertions.