NegGram (nalidixic acid, USP) is indicated for the treatment of urinary tract infections caused by susceptible gram-negative microorganisms, including the majority of E.

Coli, Enterobacter species, Klebsiella species, and Proteus species.

Disc susceptibility testing with the 30 mcg disc should be performed prior to administration of the drug, and during treatment if clinical response warrants.To reduce the development of drug-resistant bacteria and maintain effectiveness of NegGram and other antibacterial drugs, NegGram should be used only to treat or prevent infections that are proven or strongly suspected to be caused by susceptible bacteria.

When culture and susceptibility information are available, they should be considered when selecting or modifying antibacterial therapy.

In the absence of such data, local epidemiology and susceptibility patterns may contribute to the empiric selection of therapy.

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Urinary tract infection -- Inflammatory responses of the epithelium of the URINARY TRACT to microbial invasions. They are often bacterial infections with associated BACTERIURIA and PYURIA.

Infection -- Invasion of the host organism by microorganisms that can cause pathological conditions or diseases.

NegGram is contraindicated in patients with known hypersensitivity to nalidixic acid or to related compounds, infants less than three months of age, and in patients with porphyria or a history of convulsive disorders.

NegGram is contraindicated in patients undergoing concomitant therapy with melphalan or other related cancer chemotherapeutic alkylating agents because of serious gastrointestinal toxicity such as hemorrhagic ulcerative colitis or intestinal necrosis.

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Hypersensitivity -- Altered reactivity to an antigen, which can result in pathologic reactions upon subsequent exposure to that particular antigen.

Porphyria -- group of disorders characterized by the excessive production of porphyrins or their precursors that arises from abnormalities in the regulation of the porphyrin-heme pathway; acquired porphyrias, which are due to inhibition of enzymes in the metabolic pathway by a drug, toxin or abnormal metabolite, are more common than those which are inherited.

Ulcerative Colitis -- Inflammation of the COLON that is predominantly confined to the MUCOSA. Its major symptoms include DIARRHEA, rectal BLEEDING, the passage of MUCUS, and ABDOMINAL PAIN.

HEMORRHAGIC COLITIS --

Ulcer -- A lesion on the surface of the skin or a mucous surface, produced by the sloughing of inflammatory necrotic tissue.

INTESTINAL GANGRENE --

Central Nervous System (CNS) effects including convulsions, increased intracranial pressure, and toxic psychosis have been reported with nalidixic acid therapy.

Convulsive seizures have been reported with other drugs in this class.

Quinolones may also cause CNS stimulation which may lead to tremor, restlessness, lightheadedness, confusion, and hallucinations.

Therefore, nalidixic acid should be used with caution in patients with known or suspected CNS disorders, such as, cerebral arteriosclerosis or epilepsy, or other factors which predispose seizures.

(See ADVERSE REACTIONS.) If these reactions occur in patients receiving nalidixic acid, the drug should be discontinued and appropriate measures instituted.Serious and occasionally fatal hypersensitivity (anaphylactoid) reactions, some following the first dose, have been reported in patients receiving quinolone therapy.

Some reactions were accompanied by cardiovascular collapse, loss of consciousness, tingling, pharyngeal or facial edema, dyspnea, urticaria, and itching.

Only a few patients had a history of hypersensitivity reactions.

Serious anaphylactoid reactions required immediate emergency treatment with epinephrine.

Oxygen, intravenous steroids, and airway management, including intubation, should be administered as indicated.Nalidixic acid and other members of the quinolone drug class have been shown to cause arthropathy in juvenile animals.

(See PRECAUTIONS and ANIMAL PHARMACOLOGY.)Pseudomembranous colitis has been reported with nearly all antibacterial agents, including quinolones, and may range in severity from mild to life-threatening.

Therefore, it is important to consider this diagnosis in patients who present with diarrhea subsequent to the administration of antibacterial agents.Treatment with antibacterial agents alters the normal flora of the colon and may permit overgrowth of clostridia.

Studies indicate that a toxin produced by Clostridium difficile is one primary cause of "antibiotic-associated colitis".After the diagnosis of pseudomembranous colitis has been established, therapeutic measures should be initiated.

Mild cases of pseudomembranous colitis usually respond to drug discontinuation alone.

In moderate to severe cases, consideration should be given to management with fluids and electrolytes, protein supplementation, and treatment with an antibacterial drug clinically effective against C.

difficile colitis.