pentostatin

Action

Unknown. Thought to inhibit adenosine deaminase, thereby increasing levels of deoxyadenosine triphosphate in cells, blocking DNA synthesis, and inhibiting ribonucleotide reductase.

Availability

Powder for injection: 10-mg vials

Indications and dosages

➣ Hairy cell leukemia

Adults: 4 mg/m² I.V. every other week

Contraindications

• Hypersensitivity to drug

Precautions

Use cautiously in:

• renal disease, bone marrow depression

• pregnant or breastfeeding patients

• children.

Administration

• Before giving, hydrate patient with 500 to 1,000 ml of dextrose 5% and normal saline solution (or its equivalent). After administering, give 500 ml of dextrose 5% in water (D₅W) or its equivalent.

☞ Follow facility protocol for handling, administering, and disposing of chemotherapeutic drugs.

• Give by direct I.V. bolus injection or dilute with 25 to 50 ml of D₅W or normal saline solution; infuse over 20 to 30 minutes.

Adverse reactions

CNS: headache, malaise, anxiety, confusion, depression, dizziness, insomnia, nervousness, paresthesia, drowsiness, abnormal thinking, fatigue, asthenia, hallucinations, hostility, amnesia

CV: peripheral edema, cellulitis, vasculitis, hypotension, angina, tachycardia, bradycardia, phlebitis, thrombophlebitis, cardiac arrest, heart failure, hemorrhage, ventricular asystole, pericardial effusion, sinus arrest

EENT: abnormal vision, nonreactive pupils, photophobia, retinopathy, eye pain, conjunctivitis, dry or watery eyes, hearing loss, tinnitus, ear pain, epistaxis, pharyngitis, rhinitis

GI: nausea, vomiting, diarrhea, constipation, dyspepsia, abdominal pain, ileus, flatulence, stomatitis, glossitis, anorexia

GU: amenorrhea, breast lump, erectile dysfunction, decreased libido, renal calculi, renal dysfunction, renal insufficiency, renal failure

Hematologic: ecchymosis, anemia, hemolytic anemia, agranulocytosis, aplastic anemia, leukopenia, thrombocytopenia

Metabolic: hyperuricemia, hypercalcemia, hyponatremia

Musculoskeletal: myalgia, joint pain

Respiratory: cough, dyspnea, respiratory tract infection, pulmonary embolism

Skin: rash, eczema, petechiae, dry skin, pruritus, skin disorder, furunculosis, acne, alopecia, diaphoresis, photosensitivity

Other: unusual taste, gingivitis, fever, chills, pain, facial edema, lymphadenopathy, herpes simplex or herpes zoster infection, flulike symptoms, viral or bacterial infection, allergic reaction, sepsis, neoplasm

Interactions

Drug-drug. Allopurinol: hypersensitiv-ity vasculitis

Carmustine, cyclophosphamide, etoposide: potentially fatal acute pulmonary edema and hypotension

Fludarabine: severe or fatal pulmonary toxicity.

Vidarabine: increased risk and severity of adverse reactions

Drug-diagnostic tests. Calcium, liver

function tests, serum uric acid: increased values

Granulocytes, platelets, sodium, white blood cells: decreased levels

Patient monitoring

☞ Monitor CBC (including platelet count). Watch for evidence of blood dyscrasias.

• Assess kidney and liver function tests. Stay alert for evidence of organ dysfunction.

• Monitor temperature. Watch for signs and symptoms of bacterial and viral infection.

• Closely monitor vital signs and ECG, particularly for life-threatening arrhythmias, heart failure, and pulmonary edema.

Patient teaching

☞ Tell patient drug lowers resistance to infection. Instruct him to avoid crowds and to immediately report fever, cough, sore throat, and other infection symptoms.

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

• Instruct female patient of childbearing age to avoid pregnancy during drug therapy and to seek medical advice before becoming pregnant.

• 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 drugs and tests mentioned above.