BLACK BOX WARNING
- osteosarcoma reported in animal studies; do not use in patients with increased risk of osteosarcoma (Paget's disease, history of radiation therapy to bone, metabolic bone diseases, prior skeletal malignancy); use limited to 2 years lifetime
teriparatide
Brand: Forteo
⚠ BBW Prototype Drug
Drug Class: parathyroid hormone analog
Drug Family: bone agent
Subclass: recombinant PTH (1-34) anabolic agent
Organ Systems: endocrinemusculoskeletal
Mechanism of Action
Recombinant PTH(1-34) fragment that activates PTH1 receptors on osteoblasts; when given intermittently (daily injection) rather than continuously, produces net anabolic bone formation (increases osteoblast activity more than osteoclast activity), increasing bone mineral density and reducing fracture risk.
PTH1 receptor on osteoblasts
Indications
- osteoporosis in postmenopausal women at high fracture risk
- male osteoporosis
- glucocorticoid-induced osteoporosis
Contraindications
- Paget's disease of bone
- unexplained elevated alkaline phosphatase
- prior radiation therapy to skeleton
- pre-existing hypercalcemia
- metabolic bone diseases other than osteoporosis
- history of bone malignancy or skeletal metastases
Adverse Effects
Common
- nausea
- dizziness
- leg cramps
- transient hypercalcemia
- orthostatic hypotension
Serious
- osteosarcoma (rodent studies at high doses; extremely rare in clinical use)
- severe hypercalcemia
- urolithiasis
Pharmacokinetics (ADME)
| Absorption | subcutaneous injection; rapid absorption |
| Distribution | Vd ~1.7 L/kg |
| Metabolism | hepatic and peripheral (non-specific proteases) |
| Excretion | renal and biliary |
| Half-life | ~1 hour |
| Onset | months |
| Peak | 30 minutes |
| Duration | continuous daily dosing; effects sustained months after stopping |
| Protein Binding | not significant |
| Vd | 1.7 L/kg |
Drug Interactions
| Drug / Agent | Mechanism | Severity |
|---|---|---|
| digoxin | hypercalcemia from teriparatide sensitizes heart to digoxin toxicity | major |
Nursing Considerations
- Use is limited to 2 years (lifetime maximum) due to osteosarcoma risk in animal studies; confirm patient has not previously received teriparatide.
- Administer once daily SC injection; administer initially in sitting position due to transient orthostatic hypotension risk.
- Monitor serum calcium; transient hypercalcemia occurring several hours after injection; check calcium 16 hours after first dose.
- Store in refrigerator; discard 28 days after first use regardless of remaining quantity.
Clinical Pearls
- Teriparatide is the only FDA-approved anabolic bone agent that actually stimulates new bone formation rather than merely preventing resorption; it produces significantly greater fracture risk reduction than antiresorptive agents in patients with severe osteoporosis.
- After teriparatide therapy, transition to an antiresorptive agent (bisphosphonate or denosumab) is essential to preserve bone density gains, as benefits regress after discontinuation.
Safety Profile
Pregnancy avoid
Lactation avoid
Renal Adjustment Not required
Hepatic Adjustment Not required
TDM Not required
Concordance Terms
Cross-referenced clinical concepts — click any term to see all content where it appears.