pentamidine isethionate

Action

Unknown. May interfere with nuclear metabolism and synthesis of DNA, RNA, and proteins.

Availability

Aerosol: 300 mg

Injection: 300 mg/vial

Indications and dosages

➣ Pneumocystis jiroveci pneumonia

Adults and children ages 5 and older: 4 mg/kg I.V. or deep I.M. daily for 14 days

➣ To prevent P. jiroveci pneumonia in high-risk patients with human immunodeficiency virus

Adults: 300 mg by inhalation once q 4 weeks using Respigard II nebulizer

Off-label uses

• Trypanosomiasis

• Visceral leishmaniasis

Contraindications

• History of anaphylaxis from pentamidine or diamidine compounds (inhalation only)

(Note: No absolute contraindications exist for patients with P. jiroveci.)

Precautions

Use cautiously in:

• anemia, blood dyscrasias, hepatic or renal disease, hypoglycemia, diabetes mellitus, ventricular tachycardia, hypocalcemia, hypertension, hypotension

• pregnant or breastfeeding patients

• children (safety and efficacy of inhalation solution not established).

Administration

• For I.V. infusion, dilute 300 mg-vial with sterile water for injection. Withdraw prescribed dosage, then dilute further in 50 to 250 ml of dextrose 5% in water; infuse over 60 to

120 minutes.

• For I.M. use, dilute 300 mg-vial with 3 ml of sterile water for injection. Withdraw prescribed dosage; administer deep I.M. using Z-track method.

• Keep patient supine during I.M. or I.V. administration to minimize hypotension.

• For inhalation, dilute in 6 ml of sterile water and administer through nebulizer at a flow rate of 6 L/minute from 50-psi compressed air source. Don't mix inhalation solution with other drugs.

Adverse reactions

CNS: headache, disorientation, hallucinations, dizziness, confusion, fatigue, neuralgia

CV: chest pain, ECG abnormalities, syncope, vasodilation, vasculitis, phlebitis, hypertension, palpitations, arrhythmias, severe hypotension

EENT: pharyngitis

GI: nausea, vomiting, diarrhea, abdominal pain, anorexia, acute pancreatitis

Hematologic: anemia, leukopenia, thrombocytopenia

Metabolic: hypocalcemia, hypergly-cemia, hypoglycemia, hyperkalemia Musculoskeletal: myalgia

Respiratory: cough, dyspnea, congestion, pneumothorax, bronchospasm

Skin: rash, night sweats, urticaria, sterile abscess or induration at injection site

Other: metallic or bad taste, fever, chills, pain at injection site or elsewhere, edema, allergic reactions

Interactions

Drug-diagnostic tests. Blood urea

nitrogen, creatinine, liver function tests,

potassium: increased values

Calcium, hemoglobin, hematocrit,

platelets, white blood cells: decreased levels

ECG: alterations

Glucose: increased or decreased level

Patient monitoring

See Closely monitor blood pressure and blood glucose. Watch for arrhythmias and evidence of pulmonary infection, blood dyscrasias, and pancreatitis during and after I.M. or I.V. administration, until patient is stable. (Severe, life-threatening reactions may occur.)

• Assess I.V. site closely during and after I.V. administration. Know that sterile abscess, pain, or induration may occur at injection site.

• Evaluate neurologic status.

• Monitor CBC (including platelet count), calcium and potassium levels, and kidney and liver function tests.

Patient teaching

• Explain purpose of therapy. Stress importance of completing entire course of treatment.

See Teach patient to recognize and immediately report serious cardiovascular and neurologic reactions, abdominal pain, and easy bruising or bleeding.

• Teach patient how to use aerosol.

• Tell patient to notify prescriber if infection worsens.

• Advise patient to minimize GI upset by eating small, frequent servings of food and drinking plenty of fluids.

• Caution patient to avoid driving and other hazardous activities until he knows how drug affects concentration and alertness.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the tests mentioned above.