PENTAMIDINE ISOETHIONATE

PENTAMIDINE ISOETHIONATE (pen-tam'i-deen) Nebupent, Pentacarinat , Pentam 300 Classifications: antiprotozoal; Therapeutic: antiprotozoal Pregnancy Category: C

Availability

300 mg injection; 300 mg aerosol

Action

Aromatic diamide antiprotozoal drug that appears to block parasite reproduction by interfering with nucleotide (DNA, RNA), phospholipid, and protein synthesis.

Therapeutic Effect

Effective against the porozoan parasite Pneumocystis carinii in AIDS patients.

Uses

P. carinii pneumonia (PCP).

Unlabeled Uses

African trypanosomiasis and visceral leishmaniasis. (Drug supplied for the latter uses is through the Centers for Disease Control and Prevention, Atlanta, GA.)

Contraindications

QT prolongation, history of torsades de pointes; pregnancy (category C), lactation.

Cautious Use

Hypertension, hypotension; hyperglycemia; pancreatitis; hypoglycemia; hypocalcemia; blood dyscrasias; liver or kidney dysfunction; diabetes mellitus; asthma; cardiac arrhythmias.

Route & Dosage

Treatment of Pneumocystis carinii Pneumonia Adult/Child: IM/IV 4 mg/kg/d for 14–21 d; infuse IV over 60 min Prophylaxis of Pneumocystis carinii Pneumonia Adult: Inhaled 300 mg per nebulizer q3–4wk Child: IV/IM 4 mg/kg monthly

Administration

Inhaled

• Reconstitute contents of one vial in 6 mL sterile water (not saline) and administer using nebulizer.
• Do not mix with any other drug.

Intramuscular

• Dissolve contents of 1 vial (300 mg) in 3 mL sterile water for injection.
• Give deep IM into a large muscle.
• The IM injection is painful and frequently causes local reactions (pain, indurations, swelling). Select alternate sites for daily doses and institute local treatment if indicated.

Intravenous PREPARE: IV Infusion: Dissolve contents of 1 vial in 3–5 mL sterile water for injection or D5W. Further dilute in 50–250 mL of D5W.   ADMINISTER: IV Infusion: Give over 60 min.   INCOMPATIBILITIES Y-site: Aldesleukin, cephalosporins, fluconazole, foscarnet, linezolid.

• Note: IV solutions are stable at room temperature for up to 24 h. Protect solution from light.

Adverse Effects (≥1%)

CNS: Confusion, hallucinations, neuralgia, dizziness, sweating. CV: Sudden, severe hypotension, cardiac arrhythmias, ventricular tachycardia, phlebitis. GI: Anorexia, nausea, vomiting, pancreatitis, unpleasant taste. Urogenital: Acute kidney failure. Hematologic: Leukopenia, thrombocytopenia, anemia. Metabolic: Hypoglycemia, hypocalcemia, hyperkalemia. Respiratory: Cough, bronchospasm, laryngitis, shortness of breath, chest pain, pneumothorax. Skin: Stevens-Johnson syndrome, facial flush (with IV injection), local reactions at injection site.

Interactions

Drug: aminoglycosides, amphotericin B, cidofovir, cisplatin, ganciclovir, cyclosporine, vancomycin, other nephrotoxic drugs increase risk of nephrotoxicity.

Pharmacokinetics

Absorption: Readily after IM injection. Distribution: Leaves bloodstream rapidly to bind extensively to body tissues. Elimination: 50–66% in urine within 6 h; small amounts found in urine for as long as 6–8 wk. Half-Life: 6.5–13.2 h.

Nursing Implications

Assessment & Drug Effects

• Monitor BP and HR continuously during the infusion, every half hour for 2 h thereafter, and then every 4 h until BP stablizes. Sudden severe hypotension may develop after a single dose. Place patient in supine position while receiving the drug.
• Lab tests: Monitor periodically serum electrolytes, renal function, CBC with differential, platelet count, and blood glucose.
• Measure and record I&O ratio and pattern.
• Be alert and report promptly S&S of impending kidney dysfunction (e.g., changed I&O ratio, oliguria, edema). Dosage adjustment is indicated in renal failure.
• Characteristics of pneumonia in the immunocompromised patient include constant fever, scanty (if any) sputum, dyspnea, tachypnea, and cyanosis.
• Monitor temperature changes and institute measures to lower the temperature as indicated. Fever is a constant symptom in P. carinii pneumonia, but may be rapidly elevated [as high as 40° C (104° F)] shortly after drug infusion.

Patient & Family Education

• Report promptly to physician increasing respiratory difficulty.
• Monitor blood glucose for loss of glycemic control if diabetic.
• Report any unusual bruising or bleeding. Avoid using aspirin or other NSAIDs.
• Increase fluid intake (if not contraindicated) to 2–3 qt (L) per day.

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Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug