McKenna's Pharmacology for Nursing, 2e

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P A R T 2  Chemotherapeutic agents

to oestrogen stimulation. Oestrogen-receptor sites on the tumour react with circulating oestrogen, and this reaction stimulates the tumour cells to grow and divide. Several antineoplastic agents are used to block or inter­ fere with these receptor sites to prevent growth of the cancer and in some situations to actually cause cell death. Some hormones are used to block the release of gonadotropic hormones in breast or prostate cancer if the tumours are responsive to gonadotropic hormones. Others may block androgen-receptor sites directly and are useful in the treatment of advanced prostate cancers. Hormones and hormone modulators include abiraterone ( Zytiga ), anastrozole ( Arianna, Arimidex ), bicalutamide ( Calutex, Cosudex ), cabazitaxel ( Jevtana ), degare­ lix ( Firmagon ), exemestane ( Aromasin ), flutamide ( Eulexin, Flutamin ), fulvestrant ( Faslodex ), goserelin ( Zoladex ), letrozole ( Femara ), megestrol ( Megace ), nilu­ tamide ( Anandron ), tamoxifen ( Nolvadex , Tamosin ), toremifene ( Fareston ) and triptorelin ( Diphereline ) (see Table 14.5). Therapeutic actions and indications The hormones and hormone modulators used as anti­ neoplastics are receptor-site specific or hormone specific to block the stimulation of growing cancer cells that are sensitive to the presence of that hormone (see Figure 14.4). These drugs are indicated for the treat­ ment of breast cancer in postmenopausal women or in other women without ovarian function. Some drugs are indicated for the treatment of prostatic cancers that are sensitive to hormone manipulation. Table 14.5 shows usual indications for each of the hormones and hormone modulators. Pharmacokinetics These drugs are readily absorbed from the GI tract, metabolised in the liver and excreted in the urine. Caution must be used with any individual who has hepatic or renal impairment. These drugs cross the placenta and enter into breast milk. Contraindications and cautions These drugs are contraindicated during pregnancy and breastfeeding because of toxic effects on the fetus and neonate . Hypercalcaemia is a contraindication to the use of toremifene, which is known to increase calcium levels. Use caution when giving hormones and hormone modulators to anyone with a known allergy to any of these drugs. Care is necessary in people with bone marrow suppression, which is often the index for redosing and dosing levels , and in those with renal or hepatic dysfunction, which could interfere with the metabolism or excretion of these drugs and often indi- cates a need to change the dose.

scarf or hat is important for maintaining body temperature . If alopecia is an anticipated effect of drug therapy, advise the person to obtain a wig or head covering before the condition occurs to promote self-esteem and positive body image . ■ ■ Provide the following teaching: –– Follow the appropriate dosage regimen, including dates to return for further doses. –– Maintain nutrition if GI effects are severe. –– Cover the head at extremes of temperature if alopecia is anticipated. –– Plan for appropriate rest periods because fatigue and weakness are common effects of the drugs. –– Avoid situations that might lead to infection, including crowded areas, sick people and working in the soil. –– Use safety measures such as avoiding driving or using dangerous equipment, due to possible dizziness, headache and drowsiness. –– Consult with a healthcare provider, as appropriate, due to the possibility of impaired fertility. –– Use barrier contraceptives to reduce the risk of pregnancy during therapy. Evaluation ■ ■ Monitor response to the drug (alleviation of cancer being treated and palliation of signs and symptoms of cancer). suppression, GI toxicity, neurotoxicity, alopecia, renal or hepatic dysfunction, and local reactions at the injection site). ■ ■ Evaluate the effectiveness of the teaching plan (person can name the drug, dosage, possible adverse effects to watch for and specific measures to help avoid adverse effects). ■ ■ Monitor for adverse effects (bone marrow

KEY POINTS

■■ Mitotic inhibitors kill cells during the M phase and are used to treat a variety of cancers. ■■ These drugs are usually given intravenously. Extravasation could be a serious problem. ■■ Bone marrow suppression, alopecia and toxic GI effects are common adverse effects of the mitotic inhibitors.

HORMONES AND HORMONE MODULATORS

Some cancers, particularly those involving the breast tissue, ovaries, uterus, prostate and testes, are sensitive