Drug Interactions between paricalcitol and troleandomycin

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 or grapefruit. 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. Consumption of grapefruit and grapefruit juice may also alter the blood levels and effects of paricalcitol. 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.

Paricalcitol, a vitamin D analog, reduces hyperparathyroidism associated with chronic renal failure without significant increase in serum calcium levels. Serum calcium and phosphate concentrations can increase during therapy with paricalcitol and may exacerbate arrhythmias, particularly in patients receiving cardiac glycosides. Therapy with vitamin D analogs should be administered cautiously in patients with or predisposed to cardiac arrhythmias. Clinical monitoring of serum electrolyte concentrations and cardiac function is recommended. .

Troleandomycin is primarily excreted by the liver and may accumulate in patients with impaired hepatic function. In addition, the use of troleandomycin has been associated with an allergic type of cholestatic hepatitis, particularly in patients receiving the drug for more than 2 weeks or given repeated courses. Therapy with troleandomycin should be administered cautiously in patients with liver and/or biliary disease. Liver function tests should be monitored during prolonged or repeated courses of therapy, and the drug discontinued if abnormalities develop.

Clostridioides difficile-associated diarrhea (CDAD), formerly pseudomembranous colitis, has been reported with almost all antibacterial drugs and may range from mild diarrhea to fatal colitis. The most common culprits include clindamycin and lincomycin. Antibacterial therapy alters the normal flora of the colon, leading to overgrowth of C difficile, whose toxins A and B contribute to CDAD development. Morbidity and mortality are increased with hypertoxin-producing strains of C difficile; these infections can be resistant to antimicrobial therapy and may require colectomy. CDAD must be considered in all patients who present with diarrhea after antibacterial use. Since CDAD has been reported to occur more than 2 months after antibacterial use, careful medical history is necessary. Therapy with broad-spectrum antibacterials and other agents with significant antibacterial activity should be administered cautiously in patients with history of gastrointestinal disease, particularly colitis; pseudomembranous colitis (generally characterized by severe, persistent diarrhea and severe abdominal cramps, and sometimes associated with the passage of blood and mucus), if it occurs, may be more severe in these patients and may be associated with flares in underlying disease activity. Antibacterial drugs not directed against C difficile may need to be stopped if CDAD is suspected or confirmed. Appropriate fluid and electrolyte management, protein supplementation, antibacterial treatment of C difficile, and surgical evaluation should be started as clinically indicated.

Vitamin D analogs such as calciferol and ergocalciferol should not be given to patients with hypercalcemia, malabsorption syndrome, or evidence of vitamin D toxicity.

Troleandomycin is primarily excreted by the liver and may accumulate in patients with impaired hepatic function. In addition, the use of troleandomycin has been associated with an allergic type of cholestatic hepatitis, particularly in patients receiving the drug for more than 2 weeks or given repeated courses. Therapy with troleandomycin should be administered cautiously in patients with liver and/or biliary disease. Liver function tests should be monitored during prolonged or repeated courses of therapy, and the drug discontinued if abnormalities develop.

Vitamin D analogs such as calciferol and ergocalciferol should not be given to patients with hypercalcemia, malabsorption syndrome, or evidence of vitamin D toxicity.

Paricalcitol is metabolized by the liver. Parent compound and metabolites are primarily eliminated by in the bile and feces. Paricalcitol metabolites have not been characterized or identified. Metabolic and therapeutic activity of paricalcitol may be altered in patients with hepatic impairment. Therapy with paricalcitol should be administered cautiously in patients with hepatobiliary dysfunction. Clinical monitoring of hepatobiliary function, parathyroid hormone and calcium levels is recommended.

Paricalcitol is metabolized by the liver. Parent compound and metabolites are primarily eliminated by in the bile and feces. Paricalcitol metabolites have not been characterized or identified. Metabolic and therapeutic activity of paricalcitol may be altered in patients with hepatic impairment. Therapy with paricalcitol should be administered cautiously in patients with hepatobiliary dysfunction. Clinical monitoring of hepatobiliary function, parathyroid hormone and calcium levels is recommended.

Vitamin D analogs administered in the presence of hyperphosphatemia can result in precipitation of calcium-phosphate deposits within the vascular or renal systems or other soft tissue calcifications. A solubility product (Serum Calcium X Phosphate) should not exceed 70. Serum electrolyte concentrations should be corrected prior to vitamin D analog therapy and monitored during therapy.