Teriparatide (Forteo) - Uses, Dose, Side effects

Teriparatide (Forteo) is a recombinant formulation of the endogenous parathyroid hormone. It stimulates osteoblasts, increases the gastrointestinal calcium absorption, and increases renal tubular reabsorption of calcium.

Teriparatide Uses and indications:

Glucocorticoid-induced osteoporosis:
- Treatment of osteoporosis associated with sustained systemic glucocorticoid therapy in patients at high risk of fractures.
- Sustained glucocorticoid therapy is the use of prednisone at a daily dose of 5 mg or more
- Patients at high risk for fracture are those with a history of osteoporotic fracture or multiple risk factors for fracture.
- It may also be used in patients who are intolerant or have failed other available osteoporosis therapy.
Osteoporosis in men:
- To increase bone mass in men (primary or hypogonadal osteoporosis) at high risk of fractures
- It may also be used in patients who are intolerant or have failed other available osteoporosis therapy.
Osteoporosis in postmenopausal women:
- Treatment of postmenopausal women (with osteoporosis) who are at high risk for fracture.
- It may also be used in patients who are intolerant or have failed other available osteoporosis therapy.

Teriparatide dose in Adults

Dose in the treatment of Osteoporosis in men, postmenopausal women, and glucocorticoid-induced osteoporosis:

20 mcg subQ once a day for up to 2 years.
Antiresorptive therapy should be initiated to prevent bone density decline and loss of fracture efficacy after discontinuing teriparatide.

Teriparatide dose in children:

It is contraindicated in children and young adults with open epiphysis

Pregnancy Risk Factor C

It has not yet been tested in pregnant women.
It is not recommended to be used during pregnancy.

Teriparatide use during breastfeeding:

It has not been tested in breastfeeding mothers.
It is recommended that breastfeeding mothers discontinue using it.

Teriparatide dose in Renal impairment:

Adjustment in the dose is not required in patients with renal disease.

Teriparatide Dose in liver disease:

Adjustment in the dose is not required in patients with liver disease.

Common Side Effects of Teriparatide Include:

Endocrine & metabolic:
- Hypercalcemia

Less Common Side Effects of Teriparatide Include:

Cardiovascular:
- Orthostatic Hypotension
- Angina Pectoris
- Syncope
Central Nervous System:
- Dizziness
- Headache
- Insomnia
- Anxiety
- Depression
- Vertigo
Endocrine & Metabolic:
- Hyperuricemia
Gastrointestinal:
- Nausea
- Gastritis
- Dyspepsia
- Vomiting
Immunologic:
- Antibody Development
Infection:
- Herpes Zoster
Neuromuscular & Skeletal:
- Arthralgia
- Weakness
- Leg Cramps
Respiratory:
- Rhinitis
- Pharyngitis
- Dyspnea
- Pneumonia

Contraindication to Teriparatide Include:

Allergy reactions to teriparatide and any component of the formulation
Preexisting hypercalcemia
Grave renal impairment
Other than osteoporosis, there are metabolic bone diseases that can be caused by other than osteoporosis (including Paget’s disease and hyperparathyroidism).
Unexplained elevations in alkalinephosphatase
Implant radiation therapy or prior external beam radiation therapy of the skeleton
History of bone metastases and skeletal malignancies
Pregnancy
Breastfeeding
Young adults and children with open epiphysis

Warnings and precautions

Orthostatic hypotension
- It can lead to orthostatic hypotension.
- In the first four hours after administration, transient hypotension can occur.
Osteosarcoma - [US Boxed Warning]
- In animal studies, Teriparatide was associated with an increase in osteosarcoma risk regardless of its duration and dose.
- Osteosarcoma is a serious condition that can lead to bone cancer. Risk factors include:
  - Paget disease
  - Prior radiation
  - Unexplained increase in alkalinephosphatase
  - Implant radiation therapy or prior external beam radiation therapy of the skeleton
  - Children and young adults with open epiphyses.
- Avoid use in patients suffering from hyperparathyroidism, bone metastatics, history of skeletal meetastases, and pre-existing hypercalcemia.
Urolithiasis
- Urolithiasis patients should be cautious as it can increase the likelihood of developing kidney stones.

Monitor:

Blood pressure ( for orthostatic hypotension)
Urinary calcium in patients with suspected hypercalciuria and nephrolithiasis)
Evaluated bone mineral density at 1 - 2 years after initiating therapy.
Measure annual height and weight
Assess the patient for symptomatic improvement in chronic back pain
Monitor serum calcium (draw at least 16 hours after Forteo dose)
25(OH)D
Consider measuring biochemical markers of bone turnover

How to administer Teriparatide (Forteo)?

SubQ administration:
- The initial dose should be administered in the sitting or lying posture to prevent orthostasis.
- It should be injected into the thigh or abdominal wall.
- It may be administered without regard to meals or time of day.
- The dose may be administered immediately following removal from the refrigerator.
- After the first injection, each device can be used for up to 28 days
Note: The 3 mL prefilled pen [Canadian product] must be primed before each dose.

Mechanism of action of Teriparatide (Forteo):

Teriparatide (Forteo), a recombinant form of the endogenous parathyroid hormone, is available.
Teriparatide stimulates osteoblasts and increases the gastrointestinal calcium absorption.
It also increases the renal tubular calcium reabsorption. This leads to increased bone mineral density and bone mass.
It also has been shown to reduce osteoporosis-related bone fractures in postmenopausal females.

MetabolismIt is located by the liver. It has abioavailability95% and abovehalf-life eliminationDepending on whether intravenous or subcutaneous routes are used, the time between administration is approximately 5 minutes to 1 hour. TheTime to achieve peak serum concentrationIt takes approximately 30 minutes It isexcretedVia the urine as metabolites