Terbinafine 250mg Tablets

Terbinafine is an allylamine antifungal that selectively inhibits squalene epoxidase, a key enzyme in fungal ergosterol biosynthesis. This inhibition leads to a deficiency in ergosterol (a vital component of the fungal cell membrane) and an intracellular accumulation of squalene, which is toxic to the fungal cell, resulting in fungal cell death.

Urgent Side Effects: Seek Medical Help Right Away

Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor immediately or seek medical attention:

Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Signs of liver problems, including:
+ Dark urine
+ Tiredness
+ Decreased appetite
+ Upset stomach or stomach pain
+ Light-colored stools
+ Vomiting
+ Yellow skin or eyes
Depression
Cough
Chest pain or pressure, or a fast heartbeat
Blood in the urine
Lupus symptoms, such as:
+ Rash on the cheeks or other body parts
+ Change in skin color
+ Sunburn easy
+ Muscle or joint pain
+ Chest pain or shortness of breath
+ Swelling in the arms or legs (if you have a history of lupus, inform your doctor)
Changes in taste or smell, such as loss of taste or smell (although this usually resolves after stopping the medication, it may persist or be permanent)
Severe skin reactions, including:
+ Stevens-Johnson syndrome (SJS)
+ Toxic epidermal necrolysis (TEN)
+ Other serious reactions, which can affect body organs and be life-threatening
+ Signs of severe skin reactions include:
- Red, swollen, blistered, or peeling skin
- Red or irritated eyes
- Sores in the mouth, throat, nose, eyes, genitals, or skin
- Fever
- Chills
- Body aches
- Shortness of breath
- Swollen glands

Other Possible Side Effects

Most medications can cause side effects, but many people experience none or only mild symptoms. If you encounter any of the following side effects or any other concerns, contact your doctor or seek medical attention:

Headache
Stomach pain or diarrhea
Gas
Upset stomach or vomiting
Signs of a common cold

This list is not exhaustive. If you have questions or concerns about side effects, consult your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.

Before Taking This Medication: Important Information to Share with Your Doctor

It is essential to inform your doctor about the following:

Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the symptoms you experienced.
If you have liver disease, as this may affect your ability to take this medication.

This is not an exhaustive list of potential interactions. To ensure your safety, it is crucial to discuss all of your:

Prescription and over-the-counter (OTC) medications
Natural products
Vitamins
Health problems

with your doctor and pharmacist. They will help determine whether it is safe to take this medication in combination with your other medications and health conditions. Never start, stop, or adjust the dosage of any medication without first consulting your doctor.

It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication. Regular blood tests will be necessary, as directed by your doctor, to monitor your condition. Discuss any concerns or questions you have with your doctor.

Please note that it may take several weeks to experience the full effects of this medication. In the meantime, be aware that you may be more susceptible to sunburn. To minimize this risk, avoid exposure to direct sunlight, sunlamps, and tanning beds. When going outside, use sunscreen and wear protective clothing and eyewear to shield yourself from the sun.

To avoid potential interactions, limit your consumption of caffeine-containing products, such as tea, coffee, and cola, as well as chocolate. Combining these substances with this medication may cause nervousness, shakiness, and an increased heart rate.

Although rare, this medication has been associated with low white blood cell counts, which can increase the risk of infection. If you have a history of low white blood cell counts, inform your doctor. Be vigilant for signs of infection, such as fever, chills, or a sore throat, and contact your doctor immediately if you experience any of these symptoms.

In some cases, this medication has been linked to liver problems, which can be severe and potentially life-threatening. These problems can occur in individuals with or without pre-existing liver disease. Discuss your individual risk with your doctor.

Additionally, this medication has been associated with rare but potentially life-threatening blood disorders, including thrombotic thrombocytopenic purpura/hemolytic uremic syndrome (TTP/HUS). If you experience any of the following symptoms, contact your doctor right away: extreme fatigue or weakness, bruising or bleeding, dark urine or yellowing of the skin and eyes, pale skin, changes in urine output, vision changes, weakness or numbness on one side of the body, difficulty speaking or thinking, balance problems, or fever.

If you are pregnant, planning to become pregnant, or breastfeeding, it is crucial to discuss the potential benefits and risks of this medication with your doctor to ensure the best possible outcome for you and your baby.

• Drugs metabolized by CYP2D6 (e.g., tricyclic antidepressants, selective serotonin reuptake inhibitors, beta-blockers, antiarrhythmics, dextromethorphan) - terbinafine is a strong CYP2D6 inhibitor, leading to increased levels of these drugs.
• Warfarin - increased INR and bleeding risk reported.

• CYP2D6 inhibitors (e.g., cimetidine, fluconazole, amiodarone) - may increase terbinafine plasma levels.
• CYP inducers (e.g., rifampin) - may decrease terbinafine plasma levels.
• Caffeine - terbinafine decreases caffeine clearance.
• Cyclosporine - terbinafine may increase cyclosporine clearance.

• Oral contraceptives - irregular menses reported in some patients, though causality is uncertain.

• Signs and symptoms of liver dysfunction (e.g., persistent nausea, anorexia, fatigue, vomiting, right upper quadrant pain, jaundice, dark urine, pale stools)
• Signs and symptoms of severe skin reactions (e.g., rash, blistering, peeling, fever, swollen lymph nodes)
• Changes in taste or smell (dysgeusia, anosmia, hypogeusia)
• Signs of hematologic abnormalities (e.g., fever, sore throat, malaise, signs of infection)
• Signs of lupus erythematosus (e.g., joint pain, rash, fatigue)

Terbinafine is Pregnancy Category B. Animal studies have not shown harm to the fetus, but there are no adequate and well-controlled studies in pregnant women. It should be used during pregnancy only if clearly needed and the potential benefits outweigh the potential risks.

Terbinafine is excreted into breast milk. Due to the potential for serious adverse reactions in nursing infants, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother. Lactation Risk Category L3 (Moderately Safe).

Systemic terbinafine is not FDA-approved for onychomycosis in pediatric patients. It is used off-label for tinea capitis in children, with weight-based dosing. Safety and efficacy for other indications in children have not been established.

No specific dose adjustment is required based on age alone. However, geriatric patients are more likely to have decreased renal or hepatic function, which may necessitate dose adjustment or closer monitoring. Monitor for adverse effects and drug interactions.

• Terbinafine is highly effective for dermatophyte infections, particularly onychomycosis, due to its lipophilic nature and accumulation in skin and nails.
• Liver function monitoring is crucial due to the risk of hepatotoxicity, which can range from asymptomatic transaminase elevations to rare cases of liver failure.
• Patients should be counseled on the long treatment duration required for onychomycosis (6 weeks for fingernails, 12 weeks for toenails) and that clinical cure may not be evident until several months after treatment cessation as the nail grows out.
• Taste and smell disturbances are a known, though reversible, side effect that can significantly impact patient quality of life.
• Terbinafine is a potent inhibitor of CYP2D6, requiring careful consideration of co-administered medications metabolized by this enzyme.

• Itraconazole (oral)
• Fluconazole (oral)
• Griseofulvin (oral, especially for tinea capitis)
• Efinaconazole (topical, for onychomycosis)
• Tavaborole (topical, for onychomycosis)
• Ciclopirox (topical, for onychomycosis)
• Other topical antifungals (e.g., azoles, allylamines) for skin infections

If your symptoms or health issues persist or worsen, it is essential to contact your doctor promptly. To ensure safe use, never share your medication with others or take someone else's medication. This medication is accompanied by a Medication Guide, which provides crucial information for patients. Please read this guide carefully and review it again whenever you receive a refill of this medication. If you have any questions or concerns about this medication, consult with your doctor, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call your local poison control center or seek emergency medical attention. When reporting the incident, be prepared to provide details about the medication taken, the amount consumed, and the time it occurred.