Itraconazole and terbinafine are prescription antifungal medications, belonging to a class of drugs like azoles. They are used to treat a wide variety of fungal infections of the skin, nails, and other parts of the body.
If your doctor has prescribed one of these medications, you probably have questions about the proper dosage and what to watch out for. This article provides a comprehensive overview of itraconazole and terbinafine dosage guidelines, as well as precautions you should take and other medications that might interact with these antifungals.
It’s crucial that you take these medications exactly as prescribed by your doctor. Never start, stop, or change the dose of any medication without first consulting your healthcare provider. They can help you determine the most appropriate itraconazole and terbinafine dosage for your specific condition and medical history and monitor you for potential side effects or interactions.
Terbinafine: Uses, Dosage, and Administration
Terbinafine is an antifungal medicine used to treat certain types of fungal infections. It works by stopping the growth of fungi. Here’s a look at its uses, how much to take, and how to take it.
Common Uses of Terbinafine
Terbinafine is often prescribed for:
- Onychomycosis (nail fungus): It’s effective against the dermatophytes that cause nail infections, though topical treatments such as Loceryl nail lacquer may also be considered.
- Tinea infections (ringworm): This includes infections like Tinea Capitis (scalp), Corporis (body), Cruris (groin), and Pedis (foot).
Terbinafine Dosage Guidelines
The correct dose of Terbinafine depends on the type of infection you have and your age. Here are some general guidelines:
Adult Dosage:
- Onychomycosis (fingernail): 250 mg daily for 6 weeks.
- Onychomycosis (toenail): 250 mg daily for 12 weeks.
- Tinea Capitis: 250 mg daily for 6 weeks.
- Tinea Corporis, Cruris, Pedis: 250 mg daily for 2-6 weeks.
Pediatric Dosage:
- Tinea Capitis: The dose for children varies depending on their weight. You’ll need to talk to a healthcare provider about the right dose.
- For Trichophyton tonsurans, the treatment may last 2-4 weeks.
- For Microsporum canis, a longer treatment time may be needed.
How to Take Terbinafine
Here’s how to take Terbinafine correctly:
- Take the tablets with water.
- If you’re taking oral granules, take them with food. Avoid applesauce or other fruit-based foods. The acid in some foods can affect how well your body absorbs the medicine.
Important Things to Keep in Mind
- It’s important to be sure you have a fungal infection before you start taking Terbinafine for onychomycosis.
- If you have liver disease, you shouldn’t take Terbinafine. This medicine is not for people with chronic or active liver disease.
- Your doctor may want to do regular blood tests to check your liver function and blood cell counts while you’re taking this medicine.
Terbinafine: Precautions, Warnings, and Potential Interactions
Before you start taking terbinafine, you and your doctor should be aware of some potential risks and interactions.
- Kidney Problems: If you have kidney problems, your body might not clear the drug as easily. If your creatinine clearance (CrCl) is 50 mL/min or less, the drug clearance goes down about 50%. Your doctor may need to adjust your dosage.
- Liver Problems: If you have liver cirrhosis, the drug clearance is also reduced by about 50%. In general, you shouldn’t take terbinafine if you have liver problems.
- Drug Interactions: Terbinafine can interact with medications like amphetamine and warfarin. Tell your doctor about everything you’re taking, including prescriptions, over-the-counter meds, and herbal supplements.
- Other Interactions: Avoid caffeine while you’re on terbinafine. And while it’s not a hard-and-fast rule, it’s best to be careful with alcohol, too.
- Sun Sensitivity: Terbinafine can make you more sensitive to the sun. Wear sunscreen and be careful about sun exposure.
- Monitoring: Your doctor should monitor you for any blood-related, liver-related, or psychiatric issues while you’re taking terbinafine.
Itraconazole: Uses, Dosage, and Administration
Itraconazole is a medication used to treat fungal infections. It comes in different forms and dosages, depending on the type of infection you have.
Common Uses of Itraconazole
Itraconazole is often prescribed to treat:
- Onychomycosis (nail fungus)
- Esophageal candidiasis (yeast infection of the esophagus)
- Oropharyngeal candidiasis (yeast infection of the mouth and throat, also known as thrush)
- Systemic fungal infections like blastomycosis, aspergillosis, and histoplasmosis
Itraconazole Dosage Guidelines
Dosage varies depending on the infection:
- Onychomycosis:
- Fingernails: 2 treatment pulses of 200 mg every 12 hours for 1 week, separated by 3 weeks.
- Toenails: 200 mg/day orally for 12 weeks.
- Esophageal Candidiasis: 100 mg (10 mL) orally once daily for a minimum of 3 weeks.
- Oropharyngeal Candidiasis: 200 mg (20 mL) orally once daily for 1–2 weeks or 100 mg (10 mL) orally twice daily for fluconazole-unresponsive cases.
- Blastomycosis: 200 mg daily (Sporanox) or 130 mg daily (Tolsura), increased in increments to a maximum of 400mg/day or 260mg/day if needed.
Administration Instructions
How you take itraconazole matters. Follow these guidelines:
- Itraconazole capsules should be taken immediately after a full meal.
- The oral solution should be taken on an empty stomach.
Important Considerations
There are a few other things to keep in mind when taking itraconazole:
- Loading doses are sometimes recommended for severe infections to get the medication into your system quickly.
- The length of treatment depends on the specific condition being treated.
- It’s important to be aware of potential side effects, which can range from mild to serious. Talk to your doctor about what to watch out for.
Itraconazole: Precautions, Warnings, and Potential Interactions
Before you start taking itraconazole, there are a few key things to keep in mind. It’s really important to have an open conversation with your doctor about your health history and any other medications you’re taking, since itraconazole can have some serious interactions.
Contraindications
- If you have active liver disease, you should use itraconazole with caution, or it may be contraindicated altogether.
- Itraconazole is also contraindicated if you have certain heart conditions.
Drug Interactions
This is where things get tricky. According to my medical database, itraconazole has:
- Severe interactions with at least 43 other drugs
- Serious interactions with at least 173 other drugs
- Moderate interactions with at least 264 other drugs
- Minor interactions with at least 44 other drugs
That’s why it’s so important to tell your doctor about everything you’re taking, even over-the-counter meds and supplements.
Pregnancy and Lactation
Studies on women who took short courses of itraconazole during the first trimester haven’t shown a clear risk of major birth defects. However, the findings on miscarriage risk are inconclusive. If you’re pregnant or breastfeeding, you and your doctor should carefully weigh the risks and benefits of using itraconazole.
Warnings
Pay close attention to all warnings related to itraconazole, including those about potential interactions and contraindications. Your doctor can help you understand these warnings and make sure itraconazole is safe for you.
Conclusion
Itraconazole and terbinafine are both antifungal medications, but they have different uses, dosages, and potential side effects. Itraconazole is often used to treat systemic fungal infections, while terbinafine is more commonly prescribed for nail and skin infections.
It’s essential to talk to a healthcare professional to get a treatment plan tailored to your specific needs. The right dosage and how long you need to take the medication depend on your individual situation and the type of infection you have.
Whether your doctor prescribes itraconazole or terbinafine, it’s important to follow the dosage instructions carefully and keep your doctor informed about any side effects you experience. Consistent monitoring and adherence to prescribed dosages are crucial for effective and safe treatment.