TREATMENT
NONPHARMACOLOGIC
Patients with mild osteoporosis may be treated first non-pharmacologically. Lifestyle changes such as calcium and vitamin D supplementation, exercise, and smoking cessation are non-pharmacologic treatment options. Calcium carbonate and calcium citrate are common supplements. Calcium carbonate is 40% elemental calcium, whereas calcium citrate supplements are only 21% elemental calcium. Calcium supplements are best absorbed when taken with food.24 The recommended daily total calcium intake is 1200 mg.25 Only 500 to 600 milligrams of calcium can be absorbed by the GI tract at a time. Therefore, calcium supplements should be taken at least 4 to 5 hours apart.24Patients should also be counseled that calcium supplements may cause GI side effects such as bloating and constipation. To reduce side effects, patients can slowly increase the dose of calcium to a therapeutic level.
Vitamin D supplementation works best in conjunction with calcium supplementation. Vitamin D functions to regulate calcium absorption in the intestine and stimulate bone resorption and maintain the serum calcium concentration. The National Osteoporosis Foundation recommends 800 to 1000 international units of vitamin D daily.24 Lifestyle changes may be sufficient to stop the progression of osteoporosis in its early stages. Once osteoporosis becomes severe enough, pharmacotherapy is needed to stop further bone destruction and improve BMD.
PHARMACOLOGIC
After an initial fragility fracture, the risk of additional ones increases significantly, making treatment of osteoporosis essential. The National Osteoporosis Foundation recommends treating osteoporosis with pharmacotherapy in patients with a high risk of fracture (T score <-2.5) or history of fragility fracture.26 Bisphosphonates inhibit bone resorption and are considered the first-line therapy for postmenopausal women with osteoporosis. A common side effect of oral bisphosphonates is GI toxicity. Patients are advised to avoid lying down for at least 30 minutes after medication administration to avoid esophageal irritation. Oral bisphosphonates should also be taken in the morning on an empty stomach with at least 8 ounces of water. Recurrent bisphosphonate use should be avoided in patients with chronic kidney disease. Oral alendronate and risedronate are typically discontinued after 5 years of use.27 Long-term bisphosphonate use may cause an increased risk of fragility fracture due to oversuppression of bone turnover. To avoid this risk, bisphosphonate “drug holidays” are an option. Bisphosphonates accumulate over time, creating reservoirs. Even after therapy is stopped, patients continue to have therapeutic effects for 2 to 5 years.28
Bisphosphonates are available in both oral and intravenous forms. Alendronate is available in doses of 10 mg and 70 mg for daily and weekly administration, respectively. Both are available in tablet form, but the 70 mg weekly dose is also available in a dissolvable formulation. Alendronate is available in a reduced dose for osteoporosis prevention. Alendronate dosing for osteoporosis prevention is 5 mg daily or 35 mg weekly. Risedronate is dosed as 5 mg daily, 35 mg weekly, or 150 mg monthly. Intravenous bisphosphonates are indicated when oral bisphosphonates are not tolerated, only after vitamin D has been assessed and is within the normal range. Zoledronic acid is administered as a 15-minute infusion once a year.
Teriparatide (Forteo; PTH-1-34) is available for glucocorticoid-induced osteoporosis, postmenopausal women, and men with severe osteoporosis. It is indicated for patients in whom bisphosphonate treatment has failed or those who do not tolerate bisphosphonates. Teriparatide is a synthetic parathyroid hormone (PTH) that acts as an anabolic agent, stimulating bone formation, maturation, and remodeling.29 In addition to its application as a bone-building hormone, teriparatide has gained popularity for various off-label uses. These include accelerated osteosynthesis, stress fracture healing, and in the nonoperative treatment of osteoarthritis.29 Parathyroid hormone has been shown to stimulate the maturation, proliferation, and maintenance of osteoblast progenitor cells. More recently, PTH has been shown to regulate chondrocyte signaling, as well as differentiation and maturation. Further study on the chondroregenerative potential of PTH has demonstrated its efficacy as a novel disease-modifying agent in the treatment of osteoarthritis.29 Teriparatide is administered as a daily subcutaneous injection. The United States dosing is 600 mcg/2.4 mL. Adverse effects such as orthostatic hypotension and osteosarcoma may occur. BMD testing should be performed 1 to 2 years after initiation of teriparatide and every 2 years thereafter.26
Abaloparatide (Tymlos), a human parathyroid hormone, is another treatment option for postmenopausal women at risk of osteoporotic fracture. In a study comparing the efficacy of abaloparatide and teriparatide, treatment with abaloparatide was found to induce higher BMD levels in a time frame of 12 months. The BMD differences could be attributed to many factors, such as an enhanced net anabolic effect or a reduced osteoblast expression. Furthermore, the risk of developing new vertebral and nonvertebral fractures decreased in the abaloparatide group compared with the placebo group over a period of 18 months.30
Continue to: The recommended daily dose for abaloparatide...