What it's for (Indications)
- Teriparatide is indicated for the treatment of postmenopausal women with osteoporosis who are at high risk for fracture.
- This includes patients with a history of osteoporotic fracture, multiple risk factors for fracture, or those who have failed or are intolerant to other available osteoporosis therapy.
- It is also indicated for increasing bone mass in men with primary or hypogonadal osteoporosis who are at high risk for fracture.
- Furthermore, teriparatide is approved for the treatment of men and women with glucocorticoid-induced osteoporosis who are at high risk for fracture, emphasizing its role in conditions beyond typical postmenopausal or senile osteoporosis.
- The definition of "high risk" often involves patients with very low bone mineral density (T-score less than -3.
- 0), a history of vertebral or hip fracture, or those with multiple other independent risk factors for fracture.
Dosage Information
| Type | Guideline |
|---|---|
| Standard | The recommended dosage of teriparatide is 20 mcg administered once daily as a subcutaneous injection into the thigh or abdominal wall. The injection should be administered at approximately the same time each day. Patients should be instructed on proper injection technique by a healthcare professional. The maximum duration of treatment with teriparatide is 2 years over a patient's lifetime. This critical limitation is due to the potential risk of osteosarcoma observed in animal studies, which is elaborated in the Black Box Warning section. Patients should be adequately supplemented with calcium and vitamin D if dietary intake is insufficient during teriparatide therapy. Regular monitoring of serum calcium levels may be warranted, particularly at the initiation of treatment. |
Safety & Warnings
Common Side Effects
- Commonly reported side effects associated with teriparatide include nausea, leg cramps, dizziness, and joint pain (arthralgia).
- Some patients may experience orthostatic hypotension, particularly during the first few doses, manifesting as a transient feeling of lightheadedness or dizziness upon standing, which typically resolves spontaneously within a few hours.
- Injection site reactions such as pain, swelling, or bruising are also possible.
- Less common but important adverse events include hypercalcemia, which necessitates careful monitoring, and hyperuricemia.
- Patients may also report headache, depression, asthenia, and vomiting.
- It is crucial for patients to report any unusual or severe symptoms to their healthcare provider.
- Allergic reactions, though rare, are also possible and require immediate medical attention.
Serious Warnings
- Black Box Warning: **Osteosarcoma Risk**: Teriparatide (Forsteo) caused an increase in the incidence of osteosarcoma, a malignant bone tumor, in male and female rats at supraphysiological doses and duration of exposure. While the clinical relevance of this finding in humans is uncertain, a potential risk cannot be excluded. Due to this theoretical risk, teriparatide should not be used for more than 2 years over a patient's lifetime. Additionally, teriparatide is contraindicated in patients with an increased baseline risk for osteosarcoma, including those with Paget's disease of bone, unexplained elevations of alkaline phosphatase, pediatric patients with open epiphyses, a history of prior external beam or implant radiation therapy involving the skeleton, or in patients with pre-existing skeletal malignancies or bone metastases. Patients should be informed of these potential risks prior to initiating therapy and strictly adhere to the treatment duration limits.
- Patients should be advised about the potential for orthostatic hypotension, especially with initial doses, and instructed to sit or lie down if symptoms occur.
- Hypercalcemia can occur and may be exacerbated in patients with pre-existing conditions or concurrent medications; serum calcium should be monitored.
- There is an increased risk of urolithiasis; patients with active or recent urolithiasis should be carefully evaluated.
- Caution is advised when administering teriparatide to patients with moderate renal impairment, and serum and urinary calcium should be monitored.
- Patients with conditions such as Paget's disease, unexplained elevations of alkaline phosphatase, or a history of prior external beam or implant radiation therapy to the skeleton should avoid teriparatide due to increased risk factors for skeletal malignancies.
- Concomitant use with digoxin warrants caution due to hypercalcemia potentially predisposing to digoxin toxicity, necessitating careful monitoring of serum calcium and digoxin levels.
How it Works (Mechanism of Action)
Teriparatide is a recombinant human parathyroid hormone (PTH) analog, comprising the first 34 amino acids of the 84-amino acid human parathyroid hormone. It functions as an anabolic agent for bone. Unlike continuous PTH elevation, which can lead to bone resorption, intermittent daily administration of teriparatide preferentially stimulates osteoblast function (bone-forming cells) over osteoclast activity (bone-resorbing cells). This results in a net increase in bone formation, leading to an increase in bone mineral density (BMD), improved bone microarchitecture, and ultimately, enhanced bone strength and reduced fracture risk. Teriparatide also affects calcium and phosphate metabolism by increasing intestinal calcium absorption and renal tubular reabsorption of calcium, while decreasing renal tubular reabsorption of phosphate.
Commercial Brands (Alternatives)
No other brands found for this formula.