Overview
DESCRIPTION Nitrofurantoin macrocrystals, USP is a synthetic chemical of controlled crystal size. It is a stable, yellow, crystalline compound. Nitrofurantoin macrocrystals, USP is an antibacterial agent for specific urinary tract infections. It is available in 25 mg, 50 mg, and 100 mg capsules for oral administration.
Mechanism of Action
CLINICAL PHARMACOLOGY: Nitrofurantoin macrocrystals are a larger crystal form of nitrofurantoin. The absorption of Nitrofurantoin macrocrystals is slower and its excretion somewhat less when compared to nitrofurantoin. Blood concentrations at therapeutic dosage are usually low. It is highly soluble in urine, to which it may impart a brown color. Following a dose regimen of 100 mg q.i.d. for 7 days, average urinary drug recoveries (0-24 hours) on day 1 and day 7 were 37.9% and 35.0%. Unlike many drugs, the presence of food or agents delaying gastric emptying can increase the bioavailability of Nitrofurantoin macrocrystals, presumably by allowing better dissolution in gastric juices.
Indications
- INDICATIONS AND USAGE: Nitrofurantoin Capsules, USP (macrocrystals) is specifically indicated for the treatment of urinary tract infections when due to susceptible strains of Escherichia coli, enterococci, staphylococcus aureus, and certain susceptible strains of Klebsiella and Enterobacter species. Nitrofurantoin is not indicated for the treatment of pyelonephritis or perinephric abscesses. To reduce the development of drug-resistant bacteria and maintain the effectiveness of Nitrofurantoin Capsules, USP (macrocrystals) and other antibacterial drugs, Nitrofurantoin Capsules, USP...
Common Doses
- Refer to label
Dosage
Refer to FDA label for detailed dosing.
Contraindications
- CONTRAINDICATIONS: Anuria, oliguria, or significant impairment of renal function (creatinine clearance under 60 mL per minute or clinically significant elevated serum creatinine) are contraindications. Treatment of this type of patient carries an increased risk of toxicity because of impaired excretion of the drug. Because of the possibility of hemolytic anemia due to immature erythrocyte enzyme systems (glutathione instability), the drug is contraindicated in pregnant patients at term (38-42 weeks’gestation), during labor and delivery, or when the onset of labor is imminent.
Side Effects
- ADVERSE REACTIONS Respiratory: CHRONIC, SUBACUTE, OR ACUTE PULMONARY HYPERSENSITIVITY REACTIONS MAY OCCUR. CHRONIC PULMONARY REACTIONS OCCUR GENERALLY IN PATIENTS WHO HAVE RECEIVED CONTINUOUS TREATMENT FOR SIX MONTHS OR LONGER. MALAISE, DYSPNEA ON EXERTION, COUGH, AND ALTERED PULMONARY FUNCTION ARE COMMON MANIFESTATIONS WHICH CAN OCCUR INSIDIOUSLY. RADIOLOGIC AND HISTOLOGIC FINDINGS OF DIFFUSE INTERSTITIAL PNEUMONITIS OR FIBROSIS, OR BOTH, ARE ALSO COMMON MANIFESTATIONS OF THE CHRONIC PULMONARY REACTION. FEVER IS RARELY PROMINENT.
Interactions
- Drug Interactions: Antacids containing magnesium trisilicate, when administered concomitantly with nitrofurantoin, reduce both the rate and extent of absorption. The mechanism for this interaction probably is adsorption of nitrofurantoin onto the surface of magnesium trisilicate. Uricosuric drugs, such as probenecid and sulfinpyrazone, can inhibit renal tubular secretion of nitrofurantoin. The resulting increase in nitrofurantoin serum levels may increase toxicity, and the decreased urinary levels could lessen its efficacy as a urinary tract antibacterial.