McKenna's Pharmacology for Nursing, 2e

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P A R T 6  Drugs acting on the endocrine system

Adverse effects Bisphosphonates

Contraindications and cautions for use of these drugs during pregnancy and breastfeeding. Calcitonins These drugs are metabolised in the body tissues to inactive fragments, which are excreted by the kidney. Calcitonins cross the placenta and have been associ- ated with adverse effects on the fetus in animal studies. These drugs inhibit breastfeeding in animals; it is not known whether they are excreted in breast milk (see Contraindications and cautions). Salmon calcitonin can be given by injection. Peak effects are seen within 40 minutes, and the duration of effect is 8 to 24 hours. Contraindications and cautions Bisphosphonates These drugs should not be used in the presence of hypo­ calcaemia, which could be made worse by lowering calcium levels , or with a history of any allergy to bis- phosphonates to avoid hypersensitivity reactions . Fetal abnormalities have been associated with these drugs in animal trials, and they should not be used during preg- nancy unless the benefit to the mother clearly outweighs the potential risk to the fetus or neonate. Extreme caution should be used when breastfeeding because of the potential for adverse effects on the baby. Alendronate should not be used by breastfeeding mothers. Caution should be used in people with renal dysfunction, which could interfere with excretion of the drug, or with upper GI disease, which could be aggra- vated by the drug. Alendronate and risedronate need to be taken on arising in the morning, with a full glass of water, fully 30 minutes before any other food or beverage, and the person must then remain upright for at least 30 minutes; taking the drug with a full glass of water and remaining upright for at least 30 minutes facilitates delivery of the drug to the stomach. These drugs should not be given to anyone who is unable to remain upright for 30 minutes after taking the drug because serious oesophageal erosion can occur. Zoledronic acid should be used cautiously in aspirin-sensitive asthmatic people. Alendronate and rise- dronate are now available in a once-a-week formulation to decrease the number of times the person must take the drug, which should increase compliance with the drug regimen. Calcitonins These drugs should be used in pregnancy only if the benefit to the mother clearly outweighs the potential risk to the fetus. They should not be used during breastfeed- ing because the calcium-lowering effects could cause problems for the baby. These drugs should be used with caution in people with renal dysfunction or pernicious anaemia, which could be exacerbated by these drugs.

The most common adverse effects seen with bisphos- phonates are headache, nausea and diarrhoea. There is also an increase in bone pain in individuals with Paget’s disease, but this effect usually passes after a few days to a few weeks. Oesophageal erosion has been associated with alendronate if the person has not remained upright for at least 30 minutes after taking the tablets. Calcitonins The most common adverse effects seen with these drugs are flushing of the face and hands, skin rash, nausea and vomiting, urinary frequency and local inflamma- tion at the site of injection. Many of these side effects lessen with time, the time varying with each individual person. Clinically important drug–drug interactions Bisphosphonates Oral absorption of bisphosphonates is decreased if they are taken concurrently with antacids, calcium products, iron or multiple vitamins. If these drugs need to be taken, they should be separated by at least 30 minutes. GI distress may increase if bisphosphonates are combined with aspirin; this combination should be avoided if possible. Calcitonins There have been no clinically important drug–drug interactions reported with the use of calcitonins. osteoporosis in postmenopausal women and in men; treatment of glucocorticoid-induced osteoporosis; treatment of Paget’s disease in certain people. Actions: Slows normal and abnormal bone resorption without inhibiting bone formation and mineralisation. Pharmacokinetics: Route Onset Duration PO Slow Days T 1/2 : Greater than 10 days; not metabolised, but excreted in the urine. Adverse effects: Headache, nausea, diarrhoea, increased or recurrent bone pain, oesophageal erosion. Prototype summary: Alendronate Indications: Treatment and prevention of