Drug Interactions between fexinidazole and paricalcitol

Treatment with paricalcitol may require you to adjust your dietary intake of foods which contain natural or added calcium, phosphate (organic and inorganic), and vitamin D. Ingesting too much vitamin D or having elevated calcium and/or phosphorus levels in the blood and urine can lead to toxic effects, such as having an irregular heart rhythm, seizures, kidney stones, and eventual calcification of your blood vessels, cornea and/or the soft tissues in your body. Your doctor will monitor the levels of calcium and phosphorus in your blood during treatment with paricalcitol. Please speak with your healthcare team to determine if you require a specialized diet, particularly if you have reduced kidney function, and to discuss any other questions or concerns you have. You may require additional monitoring or a dose adjustment of paricalcitol if your diet changes. Fortified foods will state on their labeling how much calcium, phosphate, and/or vitamin D has been added. The National Institutes of Health, Office of Dietary Supplements also provides information on which foods contain calcium, phosphorus, and vitamin D. You should avoid abrupt changes in your dietary calcium intake and seek medical attention if you experience early symptoms of vitamin D intoxication such as weakness, fatigue, headache, drowsiness, vertigo, ringing in the ears, loss of appetite, nausea, vomiting, constipation, dry mouth, metallic taste, muscle pain, bone pain, muscle incoordination, and low muscle tone. Late symptoms may include frequent urination, excessive thirst, weight loss, conjunctivitis ("pink eye"), light sensitivity, runny nose, itching, increased body temperature, and irregular heart rhythm. 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 can enhance the levels of fexinidazole in your body. To ensure maximal oral absorption, fexinidazole should be administered with or immediately after the main meal of the day. This will make it easier for your body to absorb the medication. Use of herbal medicines and supplements during treatment with fexinidazole should be avoided. Grapefruit or grapefruit juice should not be consumed during treatment with fexinidazole. Grapefruit juice can significantly increase the blood levels and effects of fexinidazole, which can increase the risk of an irregular heart rhythm that may be serious and potentially life-threatening, although it is a rare side effect. You may be more susceptible if you have a heart condition called congenital long QT syndrome, other cardiac diseases, conduction abnormalities, or electrolyte disturbances (for example, magnesium or potassium loss due to severe or prolonged diarrhea or vomiting). You should seek immediate medical attention if you develop sudden dizziness, lightheadedness, fainting, shortness of breath, or heart palpitations during treatment with these medications, whether together or alone. Consumption of alcoholic beverages or products containing alcohol or propylene glycol during treatment with fexinidazole may occasionally trigger a reaction in some patients similar to the disulfiram reaction, which includes unpleasant effects such as flushing, throbbing in head and neck, throbbing headache, difficulty breathing, nausea, vomiting, sweating, thirst, chest pain, rapid heartbeat, palpitation, low blood pressure, dizziness, lightheadedness, blurred vision, and confusion. Rarely, more severe reactions may include abnormal heart rhythm, heart attack, heart failure, unconsciousness, convulsions, and even death. Patients treated with fexinidazole should avoid using any products containing alcohol or propylene glycol during and for at least 48 hours after completion of therapy. Talk to your doctor or pharmacist if you have questions on how to take this or other medications you are prescribed. 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.