TOPOTECAN HYDROCHLORIDE

TOPOTECAN HYDROCHLORIDE
(toe-po-tee'can)
Hycamtin
Classifications: antineoplastic; camptothecin agent; topoisomerase i inhibitor;
Therapeutic: antineoplastic
; topoisomerase i inhibitor
Pregnancy Category: D

Availability

4 mg injection

Action

Antitumor mechanism is related to inhibition of the activity of topoisomerase I, an enzyme required for DNA replication. Topoisomerase I is essential for the relaxation of supercoiled double-stranded DNA that enables replication and transcription to proceed.

Therapeutic Effect

Topotecan binds to the DNA-topoisomerase I complex. This permits uncoiling but prevents recoiling of the two strands of DNA, resulting in a permanent break in the DNA strands.

Uses

Metastatic ovarian cancer, small cell lung cancer.

Contraindications

Previous hypersensitivity to topotecan, irinotecan, or other camptothecin analogs; acute infection; severe bone marrow depression; severe thrombocytopenia; pregnancy (category D), lactation.

Cautious Use

Myelosuppression; severe renal impairment or renal failure; history of bleeding disorders; previous cytotoxic or radiation therapy.

Route & Dosage

Metastatic Ovarian Cancer and Small Cell Lung Cancer
Adult: IV 1.5 mg/m2 daily for 5 d starting on day 1 of a 21 d course. Four courses of therapy recommended. Subsequent doses can be adjusted by 0.25 mg/m2 depending on toxicity.

Renal Impairment
Clcr 20–39 mL/min: use 0.75 mg/m2
Hemodialysis: Supplementation not needed

Administration

Intravenous
  • Initiate therapy only if baseline neutrophil count ≥1500/mm3 and platelet count ≥100,000/mm3. Do not give subsequent doses until neutrophils ≥1000/mm3, platelets ≥100,000/mm3, and Hgb >9.0 mg/dL.
  • Note: Dosage adjustments to 0.75 mg/m2 are recommended with moderate renal impairment.

PREPARE: IV Infusion: Reconstitute each 4-mg vial with 4 mL sterile water for injection to yield 1 mg/mL. Withdraw the required dose and inject into 50–100 mL of NS or D5W. If skin contacts drug during preparation, wash immediately with soap and water.  

ADMINISTER: IV Infusion: Give over 30 min immediately after preparation.  

INCOMPATIBILITIES Y-site: Dexamethasone, fluorouracil, mitomycin.

  • Store vials at 20°–25° C (68°–77° F); protect from light. Reconstituted vials are stable for 24 h.

Adverse Effects (≥1%)

Body as a Whole: Asthenia, fever, fatigue. GI: Nausea, vomiting, diarrhea, constipation, abdominal pain, stomatitis, anorexia, transient elevations in liver function tests. Hematologic: Leukopenia, neutropenia, anemia, thrombocytopenia. Respiratory: Dyspnea. Skin: Alopecia.

Interactions

Drug: Increased risk of bleeding with anticoagulants, nsaids, salicylates, antiplatelet agents.

Pharmacokinetics

Distribution: 35% bound to plasma proteins. Metabolism: Undergoes pH-dependent hydrolysis. Elimination: 30% in urine. Half-Life: 2–3 h.

Nursing Implications

Assessment & Drug Effects

  • Lab tests: Obtain CBC counts with differential frequently; periodically monitor ALT.
  • Assess for GI distress, respiratory distress, neurosensory symptoms, and S&S of infection throughout therapy.

Patient & Family Education

  • Learn common adverse effects and measures to control or minimize when possible. Immediately report any distressing adverse effects to physician.
  • Avoid pregnancy during therapy.

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

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