DRUG INTERACTIONS
Methoxyflurane
Do not administer methoxyflurane to patients taking PYLERA. The concurrent use of tetracycline hydrochloride, a component of PYLERA, with methoxyflurane has been reported to result in fatal renal toxicity [See Contraindications ].
Disulfiram
Psychotic reactions have been reported in alcoholic patients who are using metronidazole, a component of PYLERA and disulfiram concurrently. PYLERA should not be given to patients who have taken disulfiram within the last 2 weeks [See Contraindications ].
Alcohol
Consumption of alcoholic beverages or administration of other products containing propylene glycol during treatment with PYLERA and for at least 3 days afterwards may cause a disulfiram-like reaction (abdominal cramps, nausea, vomiting, headaches, and flushing) due to the interaction between alcohol or propylene glycol and metronidazole, a component of PYLERA. Discontinue alcoholic beverage or other products containing propylene glycol during and for at least 3 days after therapy with PYLERA [See Contraindications ].
Oral Contraceptives
Concurrent use of PYLERA with oral contraceptive may make oral contraceptives less effective due to an interaction with the tetracycline component of PYLERA. Breakthrough bleeding has been reported. Women of child-bearing potential should use a different or additional form of contraception while taking PYLERA.
Anticoagulants
PYLERA may alter the anticoagulant effects of warfarin and other oral coumarin anticoagulants. Metronidazole has been reported to potentiate the anticoagulant effect of warfarin, and other oral coumarin anticoagulants, resulting in a prolongation of prothrombin time. Tetracycline has been shown to depress plasma prothrombin activity. Prothrombin time, International Normalized Ratio (INR), or other suitable anticoagulation tests should be closely monitored if PYLERA is administered concomitantly with warfarin. Patients should also be monitored for evidence of bleeding.
Lithium
In patients stabilized on relatively high doses of lithium, short-term use of PYLERA may cause elevation of serum lithium concentrations and signs of lithium toxicity due to the interaction between metronidazole and lithium. Serum lithium and serum creatinine concentrations should be monitored several days after beginning treatment with PYLERA to detect any increase that may precede clinical symptoms of lithium toxicity.
Antacids, Multivitamins, or Dairy Products
The absorption of PYLERA may be reduced if administered with antacids containing aluminium, calcium, or magnesium; preparations containing iron, zinc, or sodium bicarbonate; or milk or dairy products due to the interaction between these products and tetracycline. These products should not be consumed concomitantly with PYLERA. However, the clinical significance of reduced tetracycline systemic exposure is unknown as the relative contribution of systemic versus local antimicrobial activity against Helicobacter pylori has not been established.
Penicillin
Bacteriostatic drugs, such as the tetracycline class of antibiotics, may interfere with the bactericidal action of penicillin; therefore, penicillin should not be used concomitantly with PYLERA.
Inhibitors of CYP450 liver enzymes
The simultaneous administration of PYLERA and drugs that inhibit microsomal liver enzymes, such as cimetidine, may result in a prolonged half-life and decreased plasma clearance of metronidazole.
Inducers of CYP450 liver enzymes
The simultaneous administration of PYLERA and drugs that induce microsomal liver enzymes, such as phenytoin or phenobarbital, may accelerate the elimination of metronidazole, resulting in reduced plasma concentrations of metronidazole. Impaired clearance of phenytoin has also been reported in this situation. Monitor phenytoin concentrations during treatment with PYLERA.
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