In subacute pulmonary reactions, fever and eosinophilia occur less often than in the acute form. Upon cessation of therapy, recovery may require several months. If the symptoms are not recognized as being drug related and nitrofurantoin is not stopped, the symptoms may become more severe. Acute reactions are commonly manifested by fever, chills, cough, chest pain, dyspnea, pulmonary infiltration with consolidation or pleural effusion on x-ray, and eosinophilia. Acute reactions usually occur within the first week of treatment and are reversible with cessation of therapy.
Resolution often is dramatic.
Changes in ECG may occur associated with pulmonary reactions. Collapse and cyanosis have seldom been reported. Dizziness, drowsiness, amblyopia, asthenia, vertigo and nystagmus also have been reported with the use of nitrofurantoin. Benign intracranial hypertension has seldom been reported. Confusion, depression, euphoria and psychotic reactions have been reported rarely.