Posaconazole is a prescription antifungal medication used to treat and prevent serious fungal infections. It belongs to a group of drugs known as triazole antifungals. The medication works by inhibiting the growth of fungi, interfering with a substance needed to maintain their cell membranes, which leads to their destruction. This action makes it an effective treatment against a range of fungal pathogens.
Medical Uses for Posaconazole
Posaconazole is prescribed for the prevention and treatment of invasive fungal infections, which are serious conditions that can spread throughout the body. It is most often used for patients with weakened immune systems (immunocompromised). This includes individuals undergoing chemotherapy for blood cancers, those who have received a hematopoietic stem cell transplant (HSCT), or patients with graft-versus-host disease (GVHD).
The medication is a treatment for invasive aspergillosis, a severe infection that starts in the lungs and can spread to other organs. It is also used to prevent or treat infections caused by various Candida species, which can affect the bloodstream or other body parts. Additionally, one form of posaconazole treats oropharyngeal candidiasis (thrush), a fungal infection of the mouth and throat.
Proper Administration of the Tablet
The delayed-release tablet formulation of posaconazole should be taken with a full meal. Food significantly increases the amount of medication the body absorbs, which is necessary for it to reach an effective level in the blood. Without adequate food, absorption is greatly reduced, diminishing the drug’s ability to fight infection.
The delayed-release tablet must be swallowed whole and should not be crushed, chewed, or divided. Altering the tablet disrupts its delayed-release mechanism. This can cause an incorrect concentration of the drug in the body, reducing its effectiveness and potentially leading to treatment failure or increased side effects.
Doses should be taken at the same time each day to maintain a steady level of the drug in the body. If a dose is missed, take it as soon as you remember with food. However, if it is nearly time for the next scheduled dose, skip the missed one to avoid a double dose. Continue taking the medication for the entire prescribed duration, even if symptoms improve.
Potential Side Effects
Common side effects of posaconazole can be mild. Some individuals may experience low potassium levels, swelling in the arms or legs, and difficulty sleeping. The most frequently reported issues include:
- Nausea
- Vomiting
- Diarrhea
- Headache
- Fever
- Cough
- Stomach pain
More serious side effects require immediate medical attention, including the potential for liver problems. Contact a healthcare provider right away for symptoms that could indicate liver damage, such as:
- Yellowing of the skin or eyes (jaundice)
- Dark urine
- Pale-colored stools
- Severe stomach pain
- Extreme tiredness
The medication can also affect heart rhythm by causing a condition known as QT prolongation, which can lead to an irregular heartbeat. Seek immediate medical evaluation for symptoms like dizziness, fainting, palpitations, or a fast or skipping heartbeat. Severe allergic reactions are rare but can include a rash, hives, swelling of the face or tongue, and difficulty breathing.
Important Precautions and Interactions
Before starting treatment, patients should discuss their full medical history with their healthcare provider. Pre-existing conditions can increase the risk of adverse effects. Inform your doctor about any history of liver or kidney disease, as well as any personal or family history of heart conditions like a slow or irregular heartbeat or Long QT syndrome.
Posaconazole interacts with many other medications, which can alter its effectiveness or increase side effect risks. Provide your doctor with a complete list of all prescription drugs, over-the-counter medications, and supplements. Notable interactions include certain statins (simvastatin, lovastatin), ergot alkaloids used for migraines, and various medications for anxiety, seizures, or heart rhythm problems.
The drug affects the CYP3A4 enzyme system, which metabolizes many other drugs. This interaction can cause the levels of other medications to increase or decrease, leading to potential toxicity or reduced efficacy. For example, combining posaconazole with certain HIV medications or immunosuppressants requires careful dose management and monitoring by a healthcare team.