Posaconazole belongs to the class of medications called antifungals. It is used to prevent certain serious fungal infections for people 13 years of age and older whose immune systems may be weakened by other medications or diseases. Posaconazole works by killing or stopping the growth of some types of fungi (Candida and Aspergillus) that can cause infections.

It is also used to treat Aspergillus infections that have not improved with other antifungal medications or when these medications have caused side effects.

Posaconazole suspension is also used for people 13 years of age and older to treat Candida infections of the mouth or throat (thrush). 

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

Proper use of posaconazole depends on which formulation of the medication you are taking. Do not switch between taking posaconazole oral suspension and the posaconazole delayed-release tablets without talking to your doctor. The dosing between the suspension and the delayed-release tablets is different.

Delayed-release tablets:

To prevent serious fungal infections, the recommended dose of posaconazole is 300 mg (3 tablets of 100 mg) twice daily on the first day, then 300 mg (3 tablets of 100 mg) taken once daily thereafter.

For certain fungal infections that have not responded to other medications or when other medications have caused side effects, the recommended dose of posaconazole is 300 mg (3 tablets of 100 mg) twice daily on the first day, then 300 mg (3 tablets of 100 mg) taken once daily thereafter.

Posaconazole delayed-release tablets should be swallowed whole. They may be taken with or without food. Do not crush, chew, break or dissolve the tablets as this will destroy the time-release property of this medication.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

Your doctor will determine how long the duration of your treatment will be. It is important to use this medication exactly as prescribed by your doctor. Finish all this medication, even if you have started to feel better.

If you miss a dose, take it as soon as possible and continue with your regular schedule. If it is almost time for your next dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store this medication at room temperature, do not allow it to freeze, and keep it out of the reach of children.

Oral suspension:

To prevent serious fungal infections, the recommended dose of posaconazole oral suspension is 200 mg (5 mL) taken 3 times daily.

For certain fungal infections that have not responded to other medications or when other medications have caused side effects, the recommended dose of posaconazole oral suspension is 400 mg (10 mL) taken twice daily.

For the treatment of thrush, the recommended dose of posaconazole oral suspension is 100 mg (2.5 mL) taken twice daily on the first day, then 100 mg (2.5 mL) taken once daily thereafter.

Posaconazole oral suspension should be given with a meal or nutritional supplement (if food is not tolerated) to help the medication get absorbed into the body. If you are not able to take meals or nutritional supplements your doctor may recommend that you take a dose of 200 mg (5 mL) 4 times daily.

When taking the oral suspension, use the measuring spoon that is provided to measure each dose, as it gives a more accurate measurement than household teaspoons.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

Your doctor will determine how long the duration of your treatment will be. It is important to use this medication exactly as prescribed by your doctor. Finish all this medication, even if you have started to feel better.

If you miss a dose, take it as soon as possible and continue with your regular schedule. If it is almost time for your next dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Shake the bottle well before each use. The suspension should be used within 4 weeks of opening the bottle. Safely discard any suspension that remains. Store this medication at room temperature, do not allow it to freeze, and keep it out of the reach of children.

Each yellow-coated, capsule-shaped, delayed-release tablet, debossed with "100" on one side of the tablet, contains 100 mg of posaconazole. Nonmedicinal ingredients: colloidal silicon dioxide, croscarmellose sodium, hydroxypropylcellulose, hypromellose acetate succinate, magnesium stearate, microcrystalline cellulose, and Opadry II Yellow (polyvinyl alcohol partially hydrolyzed, Macrogol/PEG 3350 [polyethylene glycol 3350], titanium dioxide, talc, and iron oxide yellow).

Do not take this medication if you:

• are allergic to posaconazole or any ingredients of the medication
• are taking astemizole, atorvastatin, cisapride, lovastatin, pimozide, quinidine, simvastatin, sirolimus, or terfenadine
• are taking medications called ergot alkaloids (e.g., ergotamine, dihydroergotamine)

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• abnormal taste in the mouth
• diarrhea
• dizziness
• dry mouth
• fatigue
• gas
• headache
• loss of appetite
• nausea
• numbness, prickling, or tingling sensations
• skin rash
• sleepiness
• stomach pain
• swelling in the mouth
• vomiting
• weakness

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• abnormal heart rhythms (e.g., very fast or slow heartbeat)
• cough or shortness of breath
• signs of anemia (low red blood cells; e.g., dizziness, pale skin, unusual tiredness or weakness, shortness of breath)
• signs of clotting problems (e.g., unusual nosebleeds, bruising, blood in urine, coughing blood, bleeding gums, cuts that don’t stop bleeding)
• signs of electrolyte imbalance (e.g., muscle pain or cramps, weakness, irregular heartbeat, lack of coordination, thirst, confusion)
• signs of infection (symptoms may include fever or chills, severe diarrhea, shortness of breath, prolonged dizziness, headache, stiff neck, weight loss, or listlessness)
• signs of liver problems (e.g., yellowing of the skin or eyes, flu-like symptoms, fatigue, abdominal pain, light coloured stools, nausea, vomiting)
• swelling of the hands and feet

Stop taking the medication and seek immediate medical attention if any of the following occur:

• signs of a severe allergic reaction (e.g., hives; skin blistering or peeling; difficulty breathing; swelling of the face, throat, or tongue)

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breastfeeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Abnormal heart rhythms: This medication can increase the risk of abnormal heart rhythms. Certain medications (e.g., sotalol, quinidine, thioridazine, chlorpromazine, pimozide, moxifloxacin, mefloquine, pentamidine, arsenic trioxide, probucol, tacrolimus) can increase the risk of a type of abnormal heart rhythm called QT prolongation, and should not be used in combination with posaconazole. You are more at risk for this type of abnormal heart rhythm and its complications if you:

• are female
• are older than 65 years of age
• have a family history of sudden cardiac death
• have a history of heart disease or abnormal heart rhythms
• have a slow heart rate
• have congenital prolongation of the QT interval
• have diabetes
• have had a stroke
• have low potassium, magnesium, or calcium levels
• have nutritional deficiencies

If you have heart disease and abnormal heart rhythms, or are taking certain medications (e.g., verapamil, atazanavir), discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Allergy to other antifungals: If you are allergic to antifungals that are related to posaconazole (e.g., ketoconazole, fluconazole, itraconazole, or voriconazole), your doctor will monitor you closely while you are taking this medication. If you experience any symptoms of an allergic reaction such as a rash, contact your doctor immediately. If you experience symptoms of a serious allergic reaction (hives; difficulty breathing; swelling of the face, mouth, tongue, or throat), get immediate medical attention.

Blood problems: Rarely, serious blood problems (e.g., hemolytic uremic syndrome, thromobotic thrombocytopenic purpura) can occur while taking this medication. If you experience vomiting, diarrhea, blood in the stools, weakness, paleness, bruising, confusion, or fever, contact your doctor immediately. These rare but serious blood problems are more likely to occur when people are also taking cyclosporine or tacrolimus to prevent transplant rejection.

Decreased effectiveness: Diarrhea and vomiting are common side effects of posaconazole. Severe diarrhea or vomiting can reduce the effectiveness of this medication. Contact your doctor if you develop severe diarrhea or vomiting.

Drowsiness/reduced alertness: Posaconazole may cause drowsiness or dizziness, affecting your ability to drive or operate machinery. Avoid driving, operating machinery, or performing other potentially hazardous tasks until you have determined how this medication affects you.

Glucose: The oral suspension contains glucose. People with galactose or glucose-galactose malabsorption should check with their doctor before taking this medication.

Liver problems: Decreased liver function or liver disease can cause this medication to build up in the body, causing side effects. If you have liver problems, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

This medication can also cause liver problems. Some people experience increases in liver function tests while taking posaconazole. These increases usually return to normal when posaconazole is stopped and may return to normal without stopping treatment. Some people may experience symptoms of more severe liver problems (nausea, vomiting, abdominal pain, fatigue, yellowing of the skin or eyes, light coloured stools) while taking this medication. If you experience any of these symptoms, contact your doctor immediately. Your doctor will monitor your liver function while you are taking posaconazole.

Pregnancy: This medication should not be used during pregnancy unless the benefits outweigh the risks. People who may become pregnant should use adequate contraception while taking this medication. If you become pregnant while taking this medication, contact your doctor immediately.

Breast-feeding: It is not known if posaconazole passes into breast milk. If you are breast-feeding and taking this medication, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and effectiveness of using this medication have not been established for children under 13 years of age. The safety and effectiveness of the IV form of posaconazole has not been determined for people under 18 years of age.

For a full list of interactions, use the Drug Interaction Checker available on the Drugs.com website.

If you are taking other medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.