Posaconazole: Antifungal Medication for Use in Pets

Posaconazole is a newer member of the azole family of antifungal medications with a structure and activity that is similar to itraconazole. The main difference between posaconazole and other azole antifungals is that it can treat a broader range of fungal organisms, like fusarium, and mucorales such as Mucor and Rhizopus.

Posaconazole is also effective against strains of blastomyces spp, candida spp, aspergillus, dermatophytes, and other strains of fungi that have built a resistance to fluconazole, itraconazole, and amphotericin-B.

antifungal meds for dogs

What Animals Can Be Treated With Posaconazole?

Posaconazole is used in veterinary medicine to treat toxoplasmosis in kittens and cats, and serious fungal infections and disseminated protothecosis in dogs. It is also used to treat evasive neurologic disease equine protozoal myeloencephalitis (EPM) in horses and Isospora suis in pigs, which is an organism that causes coccidiosis, a disease that is characterized by diarrhea in suckling and recently weaned pigs.

Posaconazole Side Effects

Posaconazole is a safe and well-tolerated medication when it is administered in the appropriate dosage, but occasionally side effects can occur. The most common side effects associated with the medication include nausea, diarrhea, and vomiting. A pet may also exhibit other signs, such as dizziness, a loss of appetite, hypokalemia, low energy, polyuria, polydipsia, and restless sleep.

Posaconazole Precautions and Drug Interactions

Posaconazole should not be administered to pets with a known history of allergic reactions to fluconazole or any other drug in the azole family. It should also be used with extreme caution in patients that have heart conditions, liver disease, or kidney disease.

The drug should further be avoided in pregnant pets because posaconzole may cause fetal harm. If the pet is nursing, then consideration should be made based on the importance of the drug to the mother’s recovery.

While undergoing posaconazole treatment, the pet should be evaluated monthly by her veterinarian. A physical examination, a complete blood count, a serum biochemical profile, and a urinalysis should be performed each month to monitor the pet’s liver enzyme activities and to look for any potentially harmful adverse effects, like anemia or dramatic increases to the pet’s serum alkaline phosphatase.

Before treating your pet with posaconazole, your veterinarian should review your pet’s current medication list because some drugs can interact with it and make it less effective. Such drugs include midazolam, alfuzosin, quinidine, atorvastatin, ergotamine, and other ergot alkaloids, benzodiazepines, alpha blockers, and statin drugs.

Posaconazole Formulations for Use in Veterinary Medicine

Posaconazole is typically administered to pets in injectable, oral suspension, and delayed-release tablet formulations. Delayed-release tablets and oral suspension are non-interchangeable because the dosing of the formulations is different. Both the tablet and the oral suspension should be taken with food to help offset the side effect of nausea.

If your pet is positively diagnosed with a serious fungal infection and your vet prescribes posaconazole to treat it, then Diamondback Drugs can help you get the medicine your pet needs quickly and for less. Our veterinary compounding pharmacy specializes in creating custom compounds in dose-specific formulations that make administering doses to your pet easier and less stressful. Get a free quote for your pet’s posaconazole prescription today!

Author: Giano Panzarella