Rifampin Disease Interactions
There are 6 disease interactions with rifampin:
Pseudomembranous colitis has been reported with most antibacterial agents and may range in severity from mild to life-threatening, with an onset of up to several weeks following cessation of therapy. Antibiotic therapy can alter the normal flora of the colon and permit overgrowth of Clostridium difficile, whose toxin is believed to be a primary cause of antibiotic-associated colitis. The colitis is usually characterized by severe, persistent diarrhea and severe abdominal cramps, and may be associated with the passage of blood and mucus. The most common culprits are clindamycin, lincomycin, the aminopenicillins (amoxicillin, ampicillin), and the cephalosporins. Therapy with broad-spectrum antibiotics and other agents with significant antibacterial activity should be administered cautiously in patients with a history of gastrointestinal diseases, particularly colitis. There is some evidence that pseudomembranous colitis, if it occurs, may run a more severe course in these patients and that it may be associated with flares in their underlying disease activity. The offending antibiotic(s) should be discontinued if significant diarrhea occurs during therapy. Stool cultures for Clostridium difficile and stool assay for C. difficile toxin may be helpful diagnostically. A large bowel endoscopy may be considered to establish a definitive diagnosis in cases of severe diarrhea.
Rifampin may infrequently cause hematopoietic abnormalities such as thrombocytopenia, leukopenia, decreased hemoglobin, and acute hemolytic anemia. Hemolysis has been described as part of an immune-mediated reaction which generally occurs after gaps in therapy. Thrombocytopenia is observed most frequently in patients receiving high-dose intermittent therapy or after a lapse in therapy, but very rarely during daily administration. It is reversible if rifampin is discontinued as soon as purpura appears. Patients with preexisting bone marrow depression or blood dyscrasias should be monitored closely during rifampin therapy for further decreases in blood counts. Although rifampin-related hematologic effects are often transient, cerebral hemorrhage and fatalities have been reported with the continued administration of rifampin after the appearance of purpura.
The use of rifampin has been associated with hepatocellular injury and liver dysfunction. Hepatitis and jaundice resulting in death have occurred, mostly in patients with underlying liver disease and during coadministration with other hepatotoxic agents including other antituberculous drugs such as isoniazid and pyrazinamide. Therapy with rifampin should be administered cautiously and under strict medical supervision in patients with liver disease or a history of alcoholism. Serum transaminases (ALT, AST) and bilirubin should be measured at baseline and every 2 to 4 weeks during therapy, but keeping in mind that elevated levels may occur transiently in 10% to 15% of patients, usually during the early days of treatment. Patients should be instructed to discontinue the drug promptly and seek medical attention if signs and symptoms of hepatic injury develop, including fever, rash, anorexia, nausea, vomiting, fatigue, right upper quadrant pain, dark urine, and jaundice.
Rifampin is primarily metabolized by the liver. Patients with liver disease may be at greater risk for adverse effects from rifampin due to decreased drug clearance. In addition, the accumulation of rifampin may result in hyperbilirubinemia because rifampin competes with bilirubin for uptake by hepatocytes. Dosage adjustments are recommended in patients with liver disease. Withdrawal of rifampin therapy may be required if serum bilirubin is persistently high.
Rifampin may induce the activity of delta amino levulinic acid synthetase, an enzyme involved in the biosynthesis of porphyrins. The use of rifampin has been associated with isolated cases of porphyria exacerbation. Therapy with rifampin should be administered cautiously in patients with a history of porphyria.
Rifampin has enzyme-inducing effects that can enhance the metabolism of many endogenous substrates, including adrenal hormones, thyroid hormones, and vitamin D, the latter of which may affect serum calcium, phosphate and parathyroid hormone levels. Patients with preexisting imbalances of these hormones should be monitored more closely during long-term therapy with rifampin. In patients whose hormonal condition is stabilized on treatment, adjustments may be necessary in their treatment regimen to compensate for these effects.
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rifampin drug Interactions
There are 615 drug interactions with rifampin
Drug Interaction Classification
The classifications below are a general guideline only. It is difficult to determine the relevance of a particular drug interaction to any individual given the large number of variables.
|Major||Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit.|
|Moderate||Moderately clinically significant. Usually avoid combinations; use it only under special circumstances.|
|Minor||Minimally clinically significant. Minimize risk; assess risk and consider an alternative drug, take steps to circumvent the interaction risk and/or institute a monitoring plan.|
Do not stop taking any medications without consulting your healthcare provider.
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