It is important to recognize nitrofurantoin as possible cause of symptoms and discontinue the drug when the suspicion of pulmonary side effects arises as it can be reversible if the drug is stopped early. Liver toxicity
Hepatic reactions, including hepatitis, cholestatic jaundice, chronic active hepatitis, and hepatic necrosis, occur rarely. The onset of chronic active hepatitis may be insidious, and patients should be monitored periodically for changes in biochemical tests that would indicate liver injury. These reactions usually occur after exposure to the drug for more than 6 weeks. If signs of liver failure are observed in a patient taking nitrofurantoin, the drug should be discontinued. Re-challenge with the drug at a later date is not recommended, as the reaction may have a hypersensitivity component and recur when the drug is resumed. Neuropathy
Neuropathy is a rare side effect of taking nitrofurantoin. Patients may experience numbness and tingling in a stocking-glove pattern, which may or may not improve upon discontinuation of the drug. Pharmacology
Organisms are said to be susceptible to nitrofurantoin if their minimum inhibitory concentration is 32 μg/mL or less. The peak blood concentration of nitrofurantoin following an oral dose of nitrofurantoin 100 mg is less than 1 μg/mL and may be undetectable. Its bioavailability is about 90% and the urinary excretion is 40% tissue penetration is negligible; the drug is well concentrated in the urine: 75% of the dose is rapidly metabolised by the liver, but 25% of the dose is excreted in the urine unchanged, reliably achieving levels of 200 μg/mL or more.
Purple glove syndrome (PGS) is a poorly understood skin disease in which the extremities become swollen, discoloured and painful. PGS is potentially serious, and may require amputation. PGS is most common among elderly patients and those receiving multiple large intravenous doses of the epilepsy drug phenytoin. Compartment syndrome is a complication of PGS. Cause
Purple glove syndrome is caused by the intravenous anticonvulsant phenytoin. This medication has many already established neurological side effects, however glove syndrome is a rare, but very serious adverse effect that may lead to limb amputations. This may occur due to the administration of phenytoin with or without extravasation. The defining characteristic is a purplish to black discoloration of the extremity followed by peripheral edema and pain distal to the site of infusion. Onset is generally seen within the first few hours of administration. The true pathology of purple glove syndrome is not fully elucidated, however it is believed to be due to the crystallization of phenytoin within the blood and extravasates into the surrounding interstitium. Another mechanism may be due to the disruption of endothelial transcellular junctions followed by leaking of phenytoin into the surround soft tissues. Diagnosis
Treatment
Doctors recommend discontinuing the use of phenytoin. The application of heat can help to relieve pain. Oral phenytoin can also result in development of purple glove syndrome. References
External links
FDA: Potential Signals of Serious Risks/New Safety Information Identified by the Adverse Event Reporting System (AERS) -- January - March 2008