Tafamidis is a prescription medication for transthyretin amyloidosis, a condition where abnormal protein deposits, known as amyloid fibrils, build up in the body’s tissues. This buildup can disrupt organ function, particularly the heart and nerves. Tafamidis works as a transthyretin stabilizer, preventing the formation of these damaging protein clumps. It treats transthyretin amyloid cardiomyopathy (ATTR-CM), which thickens heart walls, and transthyretin amyloidosis with polyneuropathy, involving nerve damage.
Common Adverse Reactions
Patients taking Tafamidis may experience several common side effects. Diarrhea is a common gastrointestinal issue, often accompanied by abdominal pain. These symptoms are typically mild and might lessen as the body adjusts to the medication.
Fatigue, an unusual tiredness, is another reported side effect that can impact daily activities. Headaches are usually mild but can be disruptive. Urinary tract infections (UTIs) occur more frequently in some patients, presenting with symptoms like a burning sensation during urination or a frequent urge to urinate. Upper respiratory infections, such as common colds, may also be more likely while on this medication.
Serious Adverse Reactions
Some side effects are more severe and require immediate medical attention. Liver dysfunction, indicated by elevated liver enzymes, has been observed. Signs of liver problems include yellowing of the skin or eyes (jaundice), dark urine, or severe abdominal pain.
Allergic reactions, though rare, can occur, manifesting as a rash, itching, or swelling, particularly of the face, tongue, or throat. Severe dizziness and difficulty breathing are also signs of an allergic reaction. Tafamidis may affect existing heart conditions, leading to symptoms like irregular heartbeat, shortness of breath, or swelling in the legs.
Managing Side Effects and When to Contact a Doctor
Managing common side effects often involves practical adjustments and supportive care. For diarrhea, staying hydrated is important, and dietary modifications may help. Over-the-counter pain relievers can typically manage headaches. If fatigue persists or becomes bothersome, discussing it with a healthcare provider can lead to recommendations for lifestyle adjustments.
Prompt medical treatment is necessary for urinary tract infections to prevent complications. Do not discontinue Tafamidis without first consulting a healthcare provider, even if side effects are mild. Regular monitoring by a healthcare provider is also advised to detect any potential issues early.
Contact a doctor immediately or seek emergency medical care if any serious side effects occur, such as signs of a severe allergic reaction, symptoms of liver problems, or changes in heart function. Prompt medical evaluation is required for any of these serious concerns.
Important Drug Interactions and Warnings
Tafamidis can interact with other medications, potentially altering their effectiveness or increasing the risk of side effects. For instance, Tafamidis can increase the exposure and risk of toxicities of certain drugs that are substrates of breast cancer resistance protein (BCRP). Healthcare providers should monitor for signs of BCRP substrate-related toxicities and adjust dosages if appropriate.
There are at least 33 moderate drug interactions identified with Tafamidis. Specific medications like imatinib, methotrexate, and rosuvastatin may interact with Tafamidis, potentially increasing their serum concentrations. It is important to inform your doctor about all medications, including over-the-counter drugs, supplements, and herbal products, to assess for potential interactions.
Tafamidis also carries warnings regarding certain patient populations. It is not recommended for women who are pregnant or breastfeeding, as animal studies suggest potential harm to an unborn baby and transfer of the drug into milk. Women of reproductive potential should consider pregnancy planning and prevention during treatment. Patients with moderate hepatic impairment may experience decreased systemic exposure and increased clearance of Tafamidis, and caution is advised for those with severe hepatic impairment as the effect is not fully known. While Tafamidis may decrease serum concentrations of total thyroxine, this is generally not associated with clinical signs of hypothyroidism, but caution is still advised for patients with existing hypothyroidism.