PENTOSTATIN Drug Interactions: What You Need to Know

Drug Interactions Allopurinol and NIPENT are both associated with skin rashes. Based on clinical studies in 25 refractory patients who received both NIPENT and allopurinol, the combined use of NIPENT and allopurinol did not appear to produce a higher incidence of skin rashes than observed with NIPENT alone. There has been a report of one patient who received both drugs and experienced a hypersensitivity vasculitis that resulted in death. It was unclear whether this adverse event and subsequent death resulted from the drug combination. Biochemical studies have demonstrated that pentostatin enhances the effects of vidarabine, a purine nucleoside with antiviral activity. The combined use of vidarabine and NIPENT may result in an increase in adverse reactions associated with each drug. The therapeutic benefit of the drug combination has not been established. The combined use of NIPENT and fludarabine phosphate is not recommended because it may be associated with an increased risk of fatal pulmonary toxicity (see WARNINGS ). Acute pulmonary edema and hypotension, leading to death, have been reported in the literature in patients treated with pentostatin in combination with carmustine, etoposide and high dose cyclophosphamide as part of the ablative regimen for bone marrow transplant.

CONTRAINDICATIONS NIPENT is contraindicated: In patients who have demonstrated hypersensitivity to NIPENT.

WARNINGS See Boxed Warning . Patients with hairy cell leukemia may experience myelosuppression primarily during the first few courses of treatment. Patients with infections prior to NIPENT treatment have in some cases developed worsening of their condition leading to death, whereas others have achieved complete response. Patients with infection should be treated only when the potential benefit of treatment justifies the potential risk to the patient. Efforts should be made to control the infection before treatment is initiated or resumed. In patients with progressive hairy cell leukemia, the initial courses of NIPENT treatment were associated with worsening of neutropenia. Therefore, frequent monitoring of complete blood counts during this time is necessary. If severe neutropenia continues beyond the initial cycles, patients should be evaluated for disease status, including a bone marrow examination. Elevations in liver function tests occurred during treatment with NIPENT and were generally reversible. Renal toxicity was observed at higher doses in early studies; however, in patients treated at the recommended dose, elevations in serum creatinine were usually minor and reversible. There were some patients who began treatment with normal renal function who had evidence of mild to moderate toxicity at a final assessment (See DOSAGE AND ADMINISTRATION ). Rashes, occasionally severe, were commonly reported and may worsen with continued treatment. Withholding of treatment may be required (See DOSAGE AND ADMINISTRATION ). Acute pulmonary edema and hypotension, leading to death, have been reported in the literature in patients treated with pentostatin in combination with carmustine, etoposide and high dose cyclophosphamide as part of the ablative regimen for bone marrow transplant.

Pregnancy

Pentostatin can cause fetal harm when administered to a pregnant woman. Pentostatin was administered intravenously at doses of 0, 0.01, 0.1, or 0.75 mg/kg/day (0, 0.06, 0.6, and 4.5 mg/m 2 ) to pregnant rats on days 6 through 15 of gestation. Drug-related maternal toxicity occurred at doses of 0.1 and 0.75 mg/kg/day (0.6 and 4.5 mg/m 2 ). Teratogenic effects were observed at 0.75 mg/kg/day (4.5 mg/m 2 ) manifested by increased incidence of various skeletal malformations. In a dose range-finding study, pentostatin was administered intravenously to rats at doses of 0, 0.05, 0.1, 0.5, 0.75, or 1 mg/kg/day (0, 0.3, 0.6, 3, 4.5, 6 mg/m 2 ), on days 6 through 15 of gestation. Fetal malformations that were observed were an omphalocele at 0.05 mg/kg (0.3 mg/m 2 ), gastroschisis at 0.75 mg/kg and 1 mg/kg (4.5 and 6 mg/m 2 ), and a flexure defect of the hindlimbs at 0.75 mg/kg (4.5 mg/m 2 ). Pentostatin was also shown to be teratogenic in mice when administered as a single 2 mg/kg (6 mg/m 2 ) intraperitoneal injection on day 7 of gestation. Pentostatin was not teratogenic in rabbits when administered intravenously on days 6 through 18 of gestation at doses of 0, 0.005, 0.01, or 0.02 mg/kg/day (0, 0.015, 0.03, or 0.06 mg/m 2 ); however maternal toxicity, abortions, early deliveries, and deaths occurred in all drug-treated groups. There are no adequate and well-controlled studies in pregnant women. If NIPENT is used during pregnancy, or if the patient becomes pregnant while taking (receiving) this drug, the patient should be apprised of the potential hazard to the fetus. Women of childbearing potential receiving NIPENT should be advised to avoid becoming pregnant.