Drug Interaction Report

Pralsetinib can cause an irregular heart rhythm that may be serious and potentially life-threatening, although it is a relatively rare side effect. The risk is increased if you have low blood levels of magnesium or potassium, which can occur with bowel cleansing preparations or excessive use of medications that have a laxative effect. Do not exceed the dose and duration of use of magnesium hydroxide recommended on the product label or prescribed by your doctor. You should seek immediate medical attention if you develop sudden dizziness, lightheadedness, fainting, shortness of breath, or heart palpitations during treatment with these medications. In addition, you should let your doctor know if you experience signs and symptoms of low magnesium or potassium blood level such as weakness, tiredness, drowsiness, dizziness, confusion, tingling, numbness, muscle pain, cramps, nausea, or vomiting. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

Food should not be consumed for at least 2 hours before and at least 1 hour after taking pralsetinib. Do not consume grapefruit, grapefruit juice, any supplements that contain grapefruit, Seville oranges, or Seville orange juice as these products can increase the blood levels of pralsetinib. This may increase the risk and/or severity of serious side effects such as lung problems, liver problems, high blood pressure, fatigue, muscle and joint pain, and bleeding complications. Some sources also warn that combining these medicines could increase the risk of an irregular heart rhythm that may be serious and potentially life-threatening, although it is a relatively rare side effect. You may be more susceptible if you have a heart condition called congenital long QT syndrome, other cardiac disease, conduction abnormalities, or electrolyte disturbance (for example, magnesium or potassium loss due to severe or prolonged diarrhea or vomiting). Talk to your doctor if you have any questions or concerns. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

Calcium absorption may be increased by taking it with food. However, foods high in oxalic acid (spinach or rhubarb), or phytic acid (bran and whole grains) may decrease calcium absorption. Calcium may be taken with food to increase absorption. Consider spacing calcium administration for at least 2 hours before or after consuming foods high in oxalic acid or phytic acid. Talk to your doctor if you have any questions or concerns. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.