Table of Common Drugs and Generic Names
- Antihypocalcemic agents
- calcitriol (Rocaltrol)
- teriparatide (Forteo)
- Antihypercalcemic agents
- bisphosphonates
- alendronate (Fosamax)
- calcitonin
- calcitonin salmon (Miacalcin, Fortical)
- bisphosphonates
Disease Spotlight: Parathyroid Dysfunction
Parathyroid dysfunction is either too little PTH (hypoparathyroidism) or too much (hyperparathyroidism), and it can hit any age group.
Hypoparathyroidism is rare: PTH is absent, calcium drops (hypocalcemia), and the usual cause is accidental removal of the parathyroid glands during surgery. Hyperparathyroidism is the reverse, excess PTH driving calcium up (hypercalcemia). Primary hyperparathyroidism shows up more often in women between 60-70 years of age; secondary hyperparathyroidism is most common in chronic renal failure.
Paget's disease is a genetically linked disorder where overactive osteoclasts get replaced by enlarged, softened bone. Watch for deep bone pain, headaches, and hearing loss. Postmenopausal osteoporosis happens when falling estrogen lets calcium pull out of bone, leaving a weakened, honeycombed structure.
Antihypocalcemic Agents
These treat deficient PTH.
Therapeutic Action
Calcitriol is a vitamin D compound that regulates calcium and phosphate absorption from the small intestine, mineral resorption in bone, and phosphate reabsorption in the renal tubules, raising serum calcium. Teriparatide stimulates new bone formation and increases skeletal mass; it raises serum calcium and lowers serum phosphorus.
Indications
Hypocalcemia in patients on chronic renal dialysis, and hypocalcemia tied to hypoparathyroidism or sustained systemic glucocorticoid therapy.
Pharmacokinetics
Here are the characteristic interactions of anti hypocalcemic agents and the body in terms of absorption, distribution, metabolism, and excretion:
| Route | Onset | Peak | Duration |
|---|---|---|---|
| PO | Slow | 4 h | 3-5 d |
| Half-life (T1/2) | Metabolism | Excretion |
|---|---|---|
| 5-8 h | Liver | Bile |
Contraindications and Cautions
Allergy to any component prevents hypersensitivity reactions. Hypercalcemia or vitamin D toxicity can be worsened by drug effects. In pregnancy and lactation there is potential harm to the fetus, and calcitriol has been linked to hypercalcemia in the infant of a nursing mother. Teriparatide caused osteosarcoma in rats given high doses for most of their lifespan. Based on 18 years of postmarketing surveillance that found no increased osteosarcoma risk in treated adults, the FDA removed the boxed warning and the two-year lifetime limit from the Forteo label in 2020, so the older "two years maximum" rule no longer applies (FDA Forteo label).
Adverse Effects
CNS: weakness, headache, somnolence, irritability. GI: metallic taste, nausea, vomiting, dry mouth, constipation.
Interactions
Magnesium-containing antacids raise the risk of hypermagnesemia. Cholestyramine or mineral oil cut absorption of the antihypocalcemic agent, so separate them by at least two hours.
Nursing Considerations
Nursing Assessment
Screen for contraindications and cautions (allergy, renal stone, pregnancy). Establish a baseline: skin lesions, orientation and affect, liver evaluation, serum calcium, magnesium, and alkaline phosphatase, and bone radiographs as appropriate.
Nursing Diagnoses
Acute pain related to GI and CNS effects. Imbalanced nutrition, less than body requirements, related to GI effects.
Implementation with Rationale
Check serum calcium before and periodically during treatment so the dose can be adjusted to keep calcium in normal limits. Give supportive measures (analgesics, small frequent meals, help with activities of daily living) for CNS and GI effects, and arrange a nutritional consult if GI effects are severe. Teach drug effects and the warning signs to report.
Evaluation
Track the response (serum calcium returning to normal), watch for adverse effects (weakness, headache, GI effects), confirm the patient can name the drug, its indication, and what to watch for, and monitor compliance.
Antihypercalcemic Agents
These treat PTH excess or hypercalcemia and include bisphosphonates and calcitonin salmon. They act on serum calcium directly and do not suppress the parathyroid gland or PTH.
Therapeutic Action
Bisphosphonates slow normal and abnormal bone resorption without blocking bone formation or mineralization. Calcitonin inhibits bone resorption and lowers elevated serum calcium, and it increases renal excretion of filtered phosphate, calcium, and sodium.
Indications
Bisphosphonate treats and prevents osteoporosis in postmenopausal women and in men, treats glucocorticoid-induced osteoporosis, and treats Paget's disease. Calcitonin treats Paget's disease, postmenopausal osteoporosis, and is used in emergency treatment of hypercalcemia.
Pharmacokinetics
Here are the characteristic interactions of biphosphonates and the body in terms of absorption, distribution, metabolism, and excretion:
| Route | Onset | Peak | Duration |
|---|---|---|---|
| PO | Slow | – | Days |
| Half-life (T1/2) | Metabolism | Excretion |
|---|---|---|
| >10 days | Not metabolized | Urine |
Here are the characteristic interactions of calcitonin and the body in terms of absorption, distribution, metabolism, and excretion:
| Route | Onset | Peak | Duration |
|---|---|---|---|
| IM, subcutaneous | 15 min | 3-4 h | 8-24 h |
| Nasal | Rapid | 31-39 min | 8-24 h |
| Half-life (T1/2) | Metabolism | Excretion |
|---|---|---|
| 1.43 h | Kidneys | Urine |
Contraindications and Cautions
Allergy to any component prevents hypersensitivity reactions. Hypocalcemia is worsened by the calcium-lowering effect of bisphosphonates. Pregnancy and lactation carry potential harm to fetus or neonate. Renal dysfunction can alter excretion. Upper GI disease can be aggravated by bisphosphonates, so the patient takes the drug with a full glass of plain water and stays upright (sitting or standing) for at least 30 minutes and until after the first food of the day, because lying down raises the risk of serious esophageal erosion, ulceration, and perforation (FDA Fosamax label). Allergy to salmon or fish products is a contraindication to calcitonin, and pernicious anemia can be worsened by calcitonin.
Adverse Effects
Bisphosphonates: headache, nausea, diarrhea. Calcitonins: flushing of the face and hands, skin rash, nausea and vomiting, urinary frequency, and local inflammation at the injection site.
Interactions
Bisphosphonates: iron, antacids, or multiple vitamins cut absorption, so separate by at least 30 minutes; aspirin adds GI distress. Calcitonin has no clinically important drug-drug interaction.
Nursing Considerations
Nursing Assessment
Screen for contraindications and cautions (allergy to the drug or to fish products with salmon calcitonin, renal dysfunction, pregnancy and lactation). Establish a baseline: skin lesions, orientation and affect, abdominal exam, serum electrolytes, and renal function tests.
Nursing Diagnoses
Acute pain related to GI and skin effects. Imbalanced nutrition, less than body requirements, related to GI effects.
Implementation with Rationale
Keep the patient well hydrated to reduce renal complications. Arrange concomitant vitamin D, calcium supplements, and hormone replacement therapy if treating postmenopausal osteoporosis. Rotate injection sites and watch for inflammation with calcitonins. Check serum calcium before and periodically during treatment for dose adjustment. Order periodic renal function blood tests if using gallium. Provide comfort measures and teach drug effects and the warning signs to report.
Evaluation
Track the response (calcium returning to normal, prevention of osteoporosis complications, control of Paget's disease), watch for adverse effects (skin rash, nausea and vomiting, renal dysfunction), confirm the patient can name the drug, its indication, and what to watch for, and monitor compliance.
Frequently Asked Questions
What is the difference between antihypocalcemic and antihypercalcemic agents? Antihypocalcemic agents (calcitriol, teriparatide) raise a low serum calcium and treat deficient PTH. Antihypercalcemic agents (bisphosphonates and calcitonin) bring a high serum calcium down by slowing bone resorption. Match the drug to the direction the calcium needs to move.
Why does the patient have to stay upright after taking alendronate? Bisphosphonates can erode the esophagus if a tablet lingers there. The patient takes it with a full glass of plain water and stays sitting or standing for at least 30 minutes and until the first food of the day, which lowers the risk of esophageal ulceration and perforation (FDA Fosamax label).
Is teriparatide still limited to two years with a boxed warning for bone cancer? No. The osteosarcoma signal came from rats given high lifetime doses. After 18 years of human surveillance showed no increased risk, the FDA removed both the boxed warning and the two-year lifetime limit from the Forteo label in 2020 (FDA Forteo label).
Why does a fish or salmon allergy matter with calcitonin? The calcitonin used clinically is calcitonin salmon, so a documented allergy to salmon or fish products is a contraindication. Screen for it before the first dose.
Which labs should be monitored on parathyroid agents? Check serum calcium before starting and periodically during treatment so the dose can be titrated to keep calcium in normal limits. Add magnesium, alkaline phosphatase, and renal function tests as the specific drug and the patient's condition require.
Why is calcitonin given by injection or nasal spray instead of by mouth? Calcitonin is a peptide hormone that the gut would digest, so it is delivered intramuscularly, subcutaneously, or intranasally rather than as an oral tablet.