McKenna's Pharmacology for Nursing, 2e

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P A R T 2  Chemotherapeutic agents

Clinically important drug–drug interactions Use caution when administering imatinib with other drugs affected by the cytochrome P450 enzyme system. In addition, St John’s wort decreases the effectiveness of many of these drugs and should be avoided. When using nilotinib avoid any other drugs that are known to prolong the QT interval.

KEY POINTS

■■ Cancer cell–specific drugs have been developed to target processes that occur in cancer cells but not in healthy cells. This specificity results in fewer toxic effects than with traditional antineoplastic therapy. ■■ Protein tyrosine kinase inhibitors, epidermal growth factor inhibitors and proteasome inhibitors have been developed to target cancer cells specifically. MISCELLANEOUS ANTINEOPLASTICS Many other agents that do not fit into one of the pre­ viously discussed groups are used as antineoplastics to cause cell death. These drugs are used for treating a wide variety of cancers. Table 14.7 lists the unclas­ sified antineoplastic drugs, their indications and any special considerations associated with the drug. Specific

Care considerations for people receiving cancer cell–specific agents

These are similar to care considerations for people receiving alkylating agents.

TABLE 14.7

DRUGS IN FOCUS Miscellaneous antineoplastics

Drug name

Dosage/route

Usual indications

arsenic trioxide (Phenasen)

Induction: 0.15 mg/kg per day IV until remission Consolidation: continue 3–6 weeks after inducting for up to 25 doses

Induction and consolidation in people with acute promyelocytic leukaemia (APL) who are refractory to or relapsed from standard therapy Actions: causes damage to fusion proteins and DNA failure, leading to cell death Special considerations: monitor for cardiac toxicity; do not use during pregnancy Inhibits enzymes essential for the synthesis of DNA, causing cell death Actions: treatment of melanoma, ovarian cancer, chronic myelocytic leukaemia; in combination therapy for primary squamous cell cancers of the head and neck; also used in the treatment of sickle cell anaemia Special considerations: can cause bone marrow depression, headache, rash, GI toxicity and renal dysfunction; encourage person to drink 10–12 glasses of water each day while taking this drug Treatment of metastatic colon or rectal cancer after treatment with fluorouracil (5-FU) or given with 5-FU Actions: disrupts DNA strands during DNA synthesis, causing cell death Special considerations: can cause severe bone marrow depression, which regulates dose of the drug; causes GI toxicity, dyspnoea, and alopecia Treatment of people with metastatic ovarian cancer after failure of other agents Actions: damages DNA strand, causing cell death during cell division Special considerations: can cause severe bone marrow depression, which regulates the dose of the drug; total alopecia, GI toxicity and CNS effects may also limit the use of the drug; analgesics may be helpful

hydroxyurea (Hydrea)

80 mg/kg PO every third day; 20–30 mg/kg PO daily for continual therapy

irinotecan (Camptosar, Tecan)

125 mg/m 2 IV over 90 minutes, once a week for 4 weeks, followed by 2 weeks of rest; repeat every 6 weeks

topotecan (Hycamtin)

1.5 mg/m 2 per day IV for 5 days; as part of a 21-day course; minimum of four courses