Nitrofurantoin Concomitant Administration With Other Medications
Nitrofurantoin (Macrobid) can generally be taken at the same time as most other medications because clinically important interactions are limited to a few specific agents. [1] Macrobid administration should avoid specific drug classes that reduce nitrofurantoin absorption or urinary excretion. [1]
Concomitant Administration Usually Acceptable
Macrobid should be taken with food (ideally breakfast and dinner) to enhance tolerance and absorption. [1] Macrobid has no requirement to separate dosing from most routine prescription and over-the-counter medications beyond avoiding the contraindicated interaction classes described below. [1]
Drug Classes With No Simultaneous Use
Antacids containing magnesium trisilicate should not be used concomitantly because coadministration reduces the rate and extent of nitrofurantoin absorption. [1] Uricosuric drugs, including probenecid and sulfinpyrazone, should not be used concomitantly because these agents can inhibit renal tubular secretion of nitrofurantoin. [1]
Administration Timing Considerations
Magnesium trisilicate antacids should be avoided during nitrofurantoin therapy rather than only spaced apart, because the interaction occurs when given concomitantly and reduces absorption. [1] Uricosuric drugs should be avoided during nitrofurantoin therapy due to reduced urinary availability from inhibited tubular secretion. [1]
Practical Co-Dosing Approach
Macrobid should be taken with food when other medications are also taken with meals, when compatible. [1] When the other medication is an antacid containing magnesium trisilicate, coadministration should be avoided. [1] When the other medication is probenecid or sulfinpyrazone, coadministration should be avoided. [1]
Common Pitfalls to Avoid
Avoiding magnesium trisilicate–containing antacids prevents reduced nitrofurantoin absorption and potential loss of efficacy. [1] Avoiding probenecid and sulfinpyrazone prevents reduced renal tubular secretion and potential loss of efficacy. [1]
Information Needed for Medication-Specific Confirmation
Medication-specific interaction assessment requires the exact name of the “other medication,” including whether it is an antacid and whether it contains magnesium trisilicate. [1]