Teriparatide

Pronunciation

(ter i PAR a tide)

U.S. Brand Names

Forteo™

Synonyms

Parathyroid Hormone (1-34); Recombinant Human Parathyroid Hormone (1-34); rhPTH(1-34)

Generic Available

No

Use

Treatment of osteoporosis in postmenopausal women at high risk of fracture; treatment of primary or hypogonadal osteoporosis in men at high risk of fracture

Pregnancy Risk Factor

C

Pregnancy Implications

Effect on human fetal development has not been studied; not indicated for use in pregnant women

Lactation

Excretion in breast milk unknown/not recommended

Contraindications

Hypersensitivity to teriparatide or any component of the formulation

Warnings/Precautions

In animal studies, teriparatide has been associated with an increase in osteosarcoma; risk was dependent on both dose and duration. Use of teriparatide for longer than 2 years is not recommended. Avoid use in patients with an increased risk of osteosarcoma (including Paget's disease, prior radiation, unexplained elevation of alkaline phosphatase, or in patients with open epiphyses). Do not use in patients with a history of skeletal metastases, hyperparathyroidism, or pre-existing hypercalcemia. Exclude metabolic bone disease other than osteoporosis prior to initiating therapy. Use caution in patients with active or recent urolithiasis. Use caution in patients at risk of orthostasis (including concurrent antihypertensive therapy), or in patients who may not tolerate transient hypotension (cardiovascular or cerebrovascular disease). Use caution in patients with renal or hepatic impairment (limited data available concerning safety and efficacy). Not approved for use in pediatric patients.

Adverse Reactions

1% to 10%:

Cardiovascular: Chest pain (3%), syncope (3%)

Central nervous system: Dizziness (8%), depression (4%), vertigo (4%)

Dermatologic: Rash (5%)

Endocrine & metabolic: Hypercalcemia (transient increases noted 4-6 hours postdose in 11% of women and 6% of men)

Gastrointestinal: Nausea (9%), dyspepsia (5%), vomiting (3%), tooth disorder (2%)

Genitourinary: Hyperuricemia (3%)

Neuromuscular & skeletal: Arthralgia (10%), weakness (9%), leg cramps (3%)

Respiratory: Rhinitis (10%), pharyngitis (6%), dyspnea (4%), pneumonia (4%)

Miscellaneous: Antibodies to teriparatide (3% of women in long-term treatment; hypersensitivity reactions or decreased efficacy were not associated in preclinical trials)

Overdosage/Toxicology

No specific experience in overdose. Symptoms may include hypercalcemia, hypotension, headache, nausea, vomiting, and hypotension. Treatment is supportive (monitor serum calcium and phosphorus).

Drug Interactions

Digitalis: No effect on digitalis serum concentrations noted, however, transient hypercalcemia may increase risk of digitalis toxicity (case reports).

Ethanol/Nutrition/Herb Interactions

Ethanol: Excessive intake may increase risk of osteoporosis.

Herb/Nutraceutical: Ensure adequate calcium and vitamin D intake.

Stability

Store at 2°C to 8°C (36°F to 46°F); protect from light; do not freeze. Discard pen 28 days after first injection.

Mechanism of Action

Teriparatide is a recombinant formulation of endogenous parathyroid hormone (PTH), containing a 34-amino-acid sequence which is identical to the N-terminal portion of this hormone. The pharmacologic activity of teriparatide is similar to the physiologic activity of PTH, stimulating osteoblast function, increasing gastrointestinal calcium absorption, increasing renal tubular reabsorption of calcium. Treatment with teriparatide increases bone mineral density, bone mass, and strength. In postmenopausal women, it has been shown to decrease osteoporosis-related fractures.

Pharmacodynamics/Kinetics

Distribution: Vd: 0.12 L/kg

Metabolism: Hepatic (nonspecific proteolysis)

Bioavailability: 95%

Half-life elimination: Serum: I.V.: 5 minutes; SubQ: 1 hour

Excretion: Urine (as metabolites)

Dosage

SubQ: Adults: 20 mcg once daily; Note: Initial administration should occur under circumstances in which the patient may sit or lie down, in the event of orthostasis.

Dosage adjustment in renal impairment: No dosage adjustment required. Bioavailability and half-life increase with Clcr<30 mL/minute.

Administration

Administer by subcutaneous injection into the thigh or abdominal wall. Initial administration should occur under circumstances in which the patient may sit or lie down, in the event of orthostasis.

Monitoring Parameters

Serum calcium, serum phosphorus, uric acid; blood pressure; bone mineral density

Patient Education

Inform prescriber of all prescriptions, OTC medications, or herbal products you are taking, and any allergies you have. Do not take any new medication during therapy without consulting prescriber. Use injector pen and dispose of pen exactly as instructed; (refer to Forteo™ user manual dispensed with the medication); rotate injection sites in thigh or abdominal wall. Sit when administering to reduce possibility of falling or injury. Avoid excess alcohol and follow dietary instructions of prescriber. May cause dizziness (use caution when driving or engaged in potentially hazardous tasks until response to drug is known); nausea, vomiting, or upset stomach (small, frequent meals or frequent mouth care may help); muscle or skeletal pain, weakness, or cramping (consult prescriber for approved analgesic). Report chest pain or palpitations; respiratory difficulty; or other persistent adverse effects. Pregnancy/breast-feeding precautions: Inform prescriber if you are or intend to become pregnant. Breast-feeding is not recommended.

Nursing Implications

Patient must be instructed in use of the injector "pen".

Additional Information

Teriparatide was formerly marketed as a diagnostic agent (Perithar™); that agent was withdrawn from the market in 1997. Teriparatide (Forteo™) is manufactured through recombinant DNA technology using a strain of E. coli.

Dental Health: Effects on Dental Treatment

No significant effects or complications reported

Dental Health: Vasoconstrictor/Local Anesthetic Precautions

No information available to require special precautions

Mental Health: Effects on Mental Status

May cause dizziness or depression

Mental Health: Effects on Psychiatric Treatment

May cause orthostasis; use caution with psychotropics. May cause GI side effects; use caution with SSRIs.

Dosage Forms

Injection, solution: 250 mcg/mL (3 mL) [prefilled syringe, delivers teriparatide 20 mcg/dose]

References

Body JJ, Gaich GA, Scheele WH, et al, "A Randomized Double-blind Trial to Compare the Efficacy of Teriparatide [Recombinant Human Parathyroid Hormone (1-34)] With Alendronate in Postmenopausal Women With Osteoporosis,"J Clin Endocrinol Metab, 2002, 87(10):4528-35.

Neer RM, Arnaud CD, Zanchetta JR, et al, "Effect of Parathyroid Hormone (1-34) on Fractures and Bone Mineral Density in Postmenopausal Women With Osteoporosis,"N Engl J Med, 2001, 344(19):1434-41.

Reeve, J, "Recombinant Human Parathyroid Hormone,"BMJ, 2002, 324(7335):435-6.

International Brand Names

Forsteo® (CH, DE, DK, GB, IE, SE); Human PTH® (JP)