Medications affecting the parathyroid glands: Nursing pharmacology

Parathyroid disorders affect the parathyroids, which are four small glands located on the thyroid gland. Now, the parathyroid glands produce parathyroid hormone, or PTH for short, in response to low levels of calcium in the bloodstream. So parathyroid disorders include hypoparathyroidism, which is characterized by a decrease in PTH, and hyperparathyroidism, which is characterized by an increase in PTH.

Let’s start with hypoparathyroidism, which is treated with the active form of vitamin D3 called calcitriol, which can be given orally or intravenously, as PTH replacement therapy. Once administered, calcitriol acts by binding to PTH receptors and mimicking the actions of PTH. These include promoting the absorption of calcium from the gastrointestinal tract, as well as promoting the reabsorption of calcium from renal tubules, and to a certain extent, releasing calcium from bones into the bloodstream. As a result, calcitriol causes an increase in blood calcium levels. This medication can also be given to treat secondary hyperparathyroidism or hypocalcemia associated with chronic kidney disease, as well as pseudohypoparathyroidism.

Now, the most common side effects of calcitriol include headache and drowsiness, as well as a dry mouth and a metallic taste. Clients can also experience abdominal pain, anorexia, nausea, vomiting, diarrhea or constipation. Calcitriol may also cause blurred vision and photophobia, as well as myalgia and arthralgia. Other important side effects include hypertension, arrhythmias, hypercalcemia, pancreatitis, and anaphylactic reactions.

Alright, now contraindications of calcitriol include hypercalcemia, hyperphosphatemia, and vitamin D toxicity, while precautions should be taken in clients with cardiovascular disease and renal calculi, as well as during pregnancy and breastfeeding.

In contrast, hyperparathyroidism is treated using calcitonin, which can be administered subcutaneously, intramuscularly, and intranasally. Once administered, this medication works by inhibiting the breakdown of bones by osteoclasts and promoting calcium deposition in bones, as well as increasing the renal excretion of calcium. As a result, calcitonin causes a decrease in blood calcium levels. This medication can also be given to treat hypercalcemia, Paget disease, and postmenopausal osteoporosis. Side effects of calcitonin include headache, bronchospasm and flu-like symptoms, as well as anorexia, nausea, vomiting, and diarrhea. Clients taking calcitonin may also experience myalgia and arthralgia. Lastly, calcitonin may cause a skin rash, flushing, and even anaphylactic reactions.

Calcitonin is contraindicated in clients who are allergic to fish, since calcitonin is obtained from salmon. In addition, precautions should be taken during pregnancy, breastfeeding, and in children. Finally, calcitonin should also be used with caution in clients with hypotension or hypocalcemia.

Okay, when caring for a client with a parathyroid disorder, before administering any medication, be sure to conduct a focused assessment, noting signs of hypocalcemia like muscle cramps, hyperreflexia, paresthesias of the extremities or around the mouth, as well as positive Trousseau's and Chvostek’s signs; or signs of hypercalcemia, such as muscle weakness, depressed reflexes, and gait abnormalities. Next, review your client’s most recent laboratory test results, including calcium, phosphorus, magnesium, alkaline phosphatase, vitamin D, and PTH levels, as well as urine calcium measurements. Lastly, review diagnostic test results, including ECG and bone density tests.