pentamidine isethionate

INDICATIONS AND USAGE Pentamidine isethionate for injection is indicated for the treatment of pneumonia due to Pneumocystis carinii .

DOSAGE AND ADMINISTRATION CAUTION: DO NOT USE SODIUM CHLORIDE INJECTION, USP FOR INITIAL RECONSTITUTION BECAUSE PRECIPITATION WILL OCCUR. Pentamidine isethionate should be administered IM or IV only. The recommended regimen for adults and pediatric patients beyond 4 months of age is 4 mg/kg once a day for 14 to 21 days. Therapy for longer than 21 days with pentamidine isethionate has also been used but may be associated with increased toxicity. Intramuscular Injection The contents of one vial (300 mg) should be dissolved in 3 mL of Sterile Water for Injection, USP at 22° to 30°C (72° to 86°F). The calculated daily dose should then be withdrawn and administered by deep IM injection. Intravenous Injection The contents of one vial (300 mg) should first be dissolved in 3 to 5 mL of Sterile Water for Injection, USP, or 5% Dextrose Injection, USP at 22° to 30°C (72° to 86°F). The calculated dose of pentamidine isethionate should then be withdrawn and diluted further in 50 to 250 mL of 5% Dextrose Injection, USP. The diluted IV solutions containing pentamidine isethionate should be infused over a period of 60 minutes. Aseptic technique should be employed in preparation of all solutions. Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration whenever solution and container permit. Stability After reconstitution with sterile water, the pentamidine isethionate solution is stable for 48 hours in the original vial at room temperature if protected from light. To avoid crystallization, store at 22° to 30°C (72° to 86°F). Intravenous infusion solutions of pentamidine isethionate at 1 mg/mL and 2.5 mg/mL prepared in 5% Dextrose Injection, USP are stable at room temperature for up to 24 hours. Intravenous (IV) solutions of pentamidine isethionate have been shown to be incompatible with fluconazole and foscarnet sodium. IV solutions of pentamidine isethionate have been shown to be compatible with IV solutions of zidovudine (AZT) and diltiazem hydrochloride.

WARNINGS Fatalities due to severe hypotension, hypoglycemia, acute pancreatitis and cardiac arrhythmias have been reported in patients treated with pentamidine isethionate, both by the IM and IV routes. Severe hypotension may result after a single IM or IV dose and is more likely with rapid IV administration (see PRECAUTIONS ). The administration of the drug should, therefore, be limited to the patients in whom Pneumocystis carinii has been demonstrated. Patients should be closely monitored for the development of serious adverse reactions (see PRECAUTIONS and ADVERSE REACTIONS ). Extravasations have been reported which, in some instances, proceeded to ulceration, tissue necrosis and/or sloughing at the injection site. While not common, surgical debridement and skin grafting has been necessary in some of these cases; long-term sequelae have been reported. Prevention is the most effective means of limiting the severity of extravasation. The intravenous needle or catheter must be properly positioned and closely observed throughout the period of pentamidine isethionate administration. If extravasation occurs, the injection should be discontinued immediately and restarted in another vein. Because there are no known local treatment measures which have proven to be useful, management of the extravasation should be symptomatic.

CONTRAINDICATIONS Contraindicated in patients with a history of hypersensitivity to pentamidine isethionate.

Drug Interactions No drug interaction studies with pentamidine isethionate have been conducted. Because the nephrotoxic effects may be additive, the concomitant or sequential use of pentamidine isethionate and other nephrotoxic drugs such as aminoglycosides, amphotericin B, cisplatin, foscarnet, or vancomycin should be closely monitored and avoided, if possible.

Nursing Mothers It is not known whether pentamidine isethionate is excreted in human milk. Because of the potential for serious adverse reactions in nursing infants from pentamidine isethionate, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother. Because many drugs are excreted in human milk, pentamidine isethionate should not be given to a nursing mother unless the potential benefits are judged to outweigh the unknown risks.

ADVERSE REACTIONS CAUTION : Fatalities due to severe hypotension, hypoglycemia, acute pancreatitis and cardiac arrhythmias have been reported in patients treated with pentamidine isethionate, both by the IM and IV routes. Nephrotoxic events (increased creatinine, impaired renal function, azotemia, and renal failure) are common with the parenteral administration of pentamidine isethionate. The administration of the drug should, therefore, be limited to the patients in whom Pneumocystis carinii has been demonstrated. The most frequently reported spontaneous adverse events (1 to 30%) reported in clinical trials, regardless of their relation to pentamidine isethionate therapy were as follows (n=424): Cardiovascular: Hypotension 5.0% Gastrointestinal: Anorexia/Nausea 5.9% Hematologic: Anemia 1.2% Leukopenia 10.4% Thrombocytopenia 2.6% Hepatic: Elevated liver function tests 8.7% Metabolic: Hypoglycemia 5.9% Neurologic: Confusion/hallucinations 1.7% Skin: Sterile abscess and/or necrosis, pain, or induration at the site of IM injection 11.1% Rash 3.3% Special Senses: Bad taste 1.7% Urogenital: Azotemia 8.5% Elevated serum creatinine 23.6% Elevated blood urea nitrogen 6.6% Impaired renal function 28.8% Adverse events with a frequency of less than 1% incidence were as follows (No causal relationship to treatment has been established for these adverse events): Body as a whole: Allergic reaction (i.e. urticaria, itching, rash), anaphylaxis, arthralgia, chills, extrapulmonary pneumocystosis, headache, night sweats, and Stevens-Johnson syndrome. Cardiovascular: Abnormal ST segment of electrocardiogram, cardiac arrhythmias, cerebrovascular accident, hypertension, palpitations, phlebitis, syncope, tachycardia, vasodilatation, vasculitis and ventricular tachycardia. Gastrointestinal: Abdominal pain, diarrhea, dry mouth, dyspepsia, hematochezia, hypersalivation, melena, pancreatitis, splenomegaly, and vomiting. Hematological: Defibrination, eosinophilia, neutropenia, pancytopenia, and prolonged clotting time. Hepatic: Hepatic dysfunction, hepatitis and hepatomegaly Metabolic: Hyperglycemia, hyperkalemia, hypocalcemia, and hypomagnesemia. Neurological: Anxiety, confusion, depression, dizziness, drowsiness, emotional lability, hypesthesia, insomnia, memory loss, neuropathy, nervousness, neuralgia, paranoia, paresthesia, peripheral neuropathy, seizure, tremors, unsteady gait, and vertigo. Respiratory system: Asthma, bronchitis, bronchospasm, chest congestion, chest tightness, coryza, cyanosis, eosinophilic or interstitial pneumonitis, gagging, hemoptysis, hyperventilation, laryngitis, laryngospasm, non-specific lung disorder, nasal congestion, pleuritis, pneumothorax, rales, rhinitis, shortness of breath, and tachypnea. Skin: Desquamation, dry and breaking hair, dry skin, erythema, dermatitis, pruritus, rash, and urticaria. Special senses: Blepharitis, blurred vision, conjunctivitis, contact lens discomfort, eye pain or discomfort, loss of hearing, loss of taste, and loss of smell. Urogenital: Flank pain, hematuria, incontinence, nephritis, renal dysfunction and renal failure. From post-marketing clinical experience with pentamidine isethionate, the following adverse events have been reported: cough, diabetes mellitus/ketoacidosis, dyspnea, infiltration (extravasation–see WARNINGS ), and torsades de pointes.