Terbinafine

Terbinafine 250 mg tablets are a prescription oral antifungal used to treat fungal nail infections (onychomycosis) of the toenails and fingernails caused by dermatophytes. It belongs to a class of medications called allylamine antifungals. Visible improvement may take several months after treatment, as healthy nail growth gradually replaces the infected nail. Laboratory confirmation of fungal infection is recommended before starting therapy.

Below is a quick overview of important facts for patients and caregivers:

Terbinafine tablets are indicated for the treatment of fungal nail infections caused by dermatophytes. Its approved uses are as follows:

• Onychomycosis of the toenail (tinea unguium)
• Onychomycosis of the fingernail (tinea unguium)

Important Information:

• Infection should be confirmed through laboratory testing before treatment.
• Diagnostic tests may include:
  • Potassium hydroxide (KOH) preparation
  • Fungal culture
  • Nail biopsy

Terbinafine is intended for dermatophyte nail infections and should be used only after proper diagnosis.

Terbinafine is an allylamine antifungal that works by disrupting the fungal cell membrane. It acts by:

• Inhibiting the enzyme squalene epoxidase
• Blocking the production of ergosterol, an essential component of fungal cell membranes
• Causing the buildup of squalene inside fungal cells
• Increasing membrane permeability
• Leading to fungal cell death

This medication has demonstrated activity against dermatophytes such as:

• Trichophyton rubrum
• Trichophyton mentagrophytes

Its effectiveness depends on the fungal species involved and drug concentration

Always follow your healthcare provider’s instructions. General guidelines include:

• Terbinafine is taken by mouth as a tablet.
• It is usually taken once daily.
• May be taken with or without food.

Treatment duration depends on the type of infection:

• 6 weeks for fingernail onychomycosis
• 12 weeks for toenail onychomycosis

Do not stop treatment early unless directed by your provider.

If you miss a dose:

• Take it as soon as you remember.
• If it is less than 4 hours before your next dose, skip the missed dose.
• Do not take two doses at the same time.

The recommended dosage of terbinafine tablets depends on the affected nail.

Before starting treatment, patients should be evaluated for evidence of chronic or active liver disease. Clinical improvement may not be visible until several months after completing therapy, as healthy nail growth gradually replaces the infected nail.

What If You Overdose on Terbinafine?

Clinical experience with terbinafine overdose is limited.

• Doses up to 5 grams (20 times the usual daily dose) have been reported.
• Serious adverse reactions were not observed in reported cases.

Symptoms of overdose may include:

• Nausea
• Vomiting
• Abdominal pain
• Dizziness
• Headache
• Rash
• Frequent urination

If an overdose is suspected, seek immediate emergency medical help or contact a poison control center.

Terbinafine tablets may cause side effects, some of which can be serious.

Common Side Effects

Commonly reported Terbinafine side effects are listed below:

• Headache
• Diarrhea
• Rash
• Upset stomach (dyspepsia)
• Nausea
• Abdominal pain
• Itching (pruritus)
• Gas (flatulence)
• Abnormal liver function tests

These effects are generally mild and may resolve during treatment.

Serious Side Effects

Terbinafine tablets may cause serious adverse reactions. Seek medical attention if you experience any of the following:

Liver problems:

Liver injury, including liver failure requiring transplant or resulting in death, has been reported. Symptoms may include:

• Persistent nausea or vomiting
• Poor appetite
• Fatigue
• Upper right abdominal pain
• Yellowing of the skin or eyes (jaundice)
• Dark urine
• Pale stools

Liver function testing should be performed before starting treatment and may be monitored during therapy.

Changes in taste or smell:

• Loss or alteration of taste (may be severe or permanent)
• Loss of smell
• Weight loss
• Mood changes or anxiety

Depressive symptoms:

• Feeling sad or worthless
• Changes in sleep patterns
• Mood changes
• Loss of interest in daily activities
• Restlessness

Low white blood cell count (neutropenia):

• Increased risk of infection
• Fever or persistent sore throat

Serious skin or allergic reactions:

• Rash, hives, or blistering skin
• Peeling skin
• Swelling of the tongue, lips, throat, or face
• Trouble breathing or swallowing
• Fever with skin eruption
• Swollen lymph nodes

Lupus flare:

• Worsening rash
• Increased sensitivity to sunlight

Blood clotting problems:

• Unexplained bruising
• Unusual bleeding

This is not a complete list of side effects. Contact your healthcare provider for medical advice about adverse reactions. You may report side effects to the FDA at 1-800-FDA-1088 or visit MedWatch.

Terbinafine tablets are associated with serious adverse reactions and should be used under appropriate medical supervision.

What Are the Warnings for Terbinafine?

While using this medication, the following warnings should be considered:

• Liver injury (hepatotoxicity): Not for patients with chronic or active liver disease. Perform liver function tests before starting treatment. Stop immediately if symptoms such as abdominal pain, nausea, fatigue, jaundice, dark urine, or pale stools occur.
• Taste disturbance (including loss of taste): May cause decreased appetite, weight loss, anxiety, or depression. Discontinue if significant changes occur.
• Smell disturbance (including loss of smell): May be prolonged or permanent. Stop treatment if symptoms develop.
• Depressive symptoms: Mood changes have been reported. Patients should report depression or behavioral changes.
• Blood abnormalities: Decreased white blood cell counts and rare severe neutropenia have occurred. Consider blood monitoring if treatment exceeds 6 weeks.
• Serious skin or allergic reactions: Including Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and DRESS syndrome. Discontinue immediately if rash, blistering, peeling skin, or hypersensitivity symptoms appear.
• Lupus erythematosus: New or worsening lupus has been reported. Discontinue if symptoms occur.
• Thrombotic microangiopathy (TMA): Rare but serious blood disorder (including TTP and HUS). Stop treatment if symptoms or abnormal labs suggest TMA.

What Are the Precautions for Terbinafine?

Before and during treatment, consider the following:

• Perform baseline liver function tests before initiation.
• Monitor liver function periodically during therapy.
• Use caution in patients with renal impairment (creatinine clearance <50 mL/min).
• Use caution in patients with lupus or weakened immune systems.
• Monitor for signs of secondary infection if hematologic abnormalities are suspected.
• Terbinafine inhibits CYP2D6 and may alter the levels of certain medications.
• Advise patients to report persistent gastrointestinal symptoms, skin rash, mood changes, and taste or smell disturbances.
• Minimize unnecessary exposure to sunlight if skin sensitivity occurs.
• Excessive alcohol use may increase the risk of liver toxicity during terbinafine treatment.

Pregnancy and Breastfeeding

Pregnancy:

Available data from postmarketing cases in pregnant women are insufficient to evaluate a drug-associated risk. Use during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Breastfeeding:

Terbinafine is present in human breast milk following oral administration. There are no adequate data on the effects on milk production or on breastfed infants. The developmental and health advantages of breastfeeding should be considered along with the mother’s clinical need for terbinafine and any potential adverse effects on the infant.

Terbinafine is a CYP450 2D6 inhibitor and may alter the levels of medications metabolized by this pathway. Monitoring or dose adjustments may be required. Drugs that may require caution or monitoring are as follows:

• Tricyclic antidepressants (TCAs)
• Selective serotonin reuptake inhibitors (SSRIs)
• Beta-blockers
• Class 1C antiarrhythmics (e.g., flecainide, propafenone)
• Monoamine oxidase inhibitors (MAO-B inhibitors)

Additional important drug interactions are listed in the table below:

Other antifungal medications may be used depending on the type and severity of fungal infection, patient comorbidities, and drug interaction profile.

Brand availability may vary by location and supply. Treatment selection should be determined by a healthcare provider based on infection type, liver function, drug interactions, and patient-specific factors.

Prescription antifungal medications may be costly at many U.S. retail pharmacies. Ordering Terbinafine tablets online from Polar Bear Meds helps reduce overall costs while maintaining safety, quality, and reliability.

• Competitive pricing compared to many U.S. retail pharmacies.
• Medications sourced from licensed and reputable Canadian pharmacies.
• Quality-controlled and properly dispensed prescription products.
• Fast and secure shipping across the United States, typically within 3-5 business days via Xpress Post.
• Shipping timelines may vary depending on processing requirements and location.
• Discreet packaging with order tracking for added security.
• Simple online ordering with easy prescription upload.
• Transparent pricing with no hidden fees.
• U.S. customers can order with a valid prescription.
• Dedicated customer support team to assist with prescriptions, orders, and delivery questions.
• Additional savings with coupon code WELCOMEPB10: 10% off your first order.

All Terbinafine orders require a valid prescription. Medications are dispensed by licensed pharmacies that comply with applicable pharmacy regulations and safety standards.

• https://dailymed.nlm.nih.gov/dailymed/lookup.cfm?setid=6dc279cc-9861-4fa8-8083-ca3b3c57b513
• https://www.ncbi.nlm.nih.gov/books/NBK545218/