How Do Parathyroid Hormone Analogs Work?

Parathyroid hormone (PTH) analogs are a synthetic form of PTH used to treat osteoporosis (bones become weak and brittle because of decreased density of the bone caused by hormonal imbalance or fracture) in the body. PTH regulates the distribution of calcium and phosphate in the body.

Increased PTH levels in the body increase the calcium level in the blood by transferring calcium from the bones into the blood. It also increases the absorption of calcium by the intestine and renal tubules in the kidney. The calcium levels in the blood decrease with a decrease in PTH levels. However, the periodic administration of recombinant PTH stimulates bone formation and treats osteoporosis in both men and women.

Recombinant PTH increases bone calcium levels, but each drug has its unique approach to attain the required result.

Abaloparatide is a synthetic peptide analog of human PTH-related protein (hPTHrP). Naturally occurring hPTHrP regulates bone formation along with other functions. Abaloparatide works as an anabolic agent for bone by acting as an agonist on the PTH type 1 receptor and activating signaling pathways expressed in osteoblasts and osteoclasts. A PTH-related protein analog is used for the treatment of osteoporosis in postmenopausal women at risk for fracture.

Human PTH, the recombinant form raises serum calcium levels by increasing renal tubular calcium reabsorption, intestinal calcium absorption, and bone turnover, which releases calcium into the circulation.

Teriparatide is a recombinant human PTH that stimulates osteoblast function, increases calcium absorption, and increases renal tubular reabsorption of calcium, thus increasing bone mineral density, bone mass, and strength.

PTH analogs are given as subcutaneous injections to treat:

• Osteoporosis
• Treatment of postmenopausal women with osteoporosis at high risk for fracture
• Increase bone mass in men with primary or hypogonadal osteoporosis
• Treatment of men and women with osteoporosis associated with sustained systemic glucocorticoid therapy at high risk for fracture, or have failed or are intolerant to other available therapy
  • Hypocalcemia

Side effects of PTH analogs include:

• Injection site reactions
• Nausea and vomiting
• Diarrhea or constipation
• Abdominal discomfort
• Dizziness
• Headache
• Vertigo (spinning sensation)
• Fatigue
• Irritability
• Palpitations
• Hypertension
• Orthostatic hypotension (decrease in blood pressure while standing from sitting or lying position)
• Upper respiratory tract infection
• Muscle and joint pains
• Paresthesia
• Sleeplessness
• Hypercalcemia (high calcium levels in the blood)
• Hypocalcemia (low calcium levels in the blood)
• Seizures
• Anaphylaxis (life-threatening allergic reactions)

The information contained herein is not intended to cover all possible side effects, precautions, warnings, drug interactions, allergic reactions, or adverse effects. Check with your doctor or pharmacist to make sure these drugs do not cause any harm when you take them along with other medicines. Never stop taking your medication and never change your dose or frequency without consulting your doctor.

Generic and brand names of PTH analog drugs include:

• Abaloparatide
• Bonsity
• Forteo
• Human parathyroid hormone, recombinant
• Natpara
• Parathyroid hormone
• Teriparatide
• Tymlos