Teriparatide
EmergingRecombinant PTH 1-34 — first true bone-ANABOLIC drug, given as daily SC injection up to 2 years for severe osteoporosis. | Peptide · Injectable
Aliases (4)
▸ Reconstitution Lyophilized peptide
Reconstitute lyophilized peptide with bacteriostatic water (BAC) using sterile technique. Calculator below converts vial mg + diluent mL into syringe units.
- 1 Wipe BAC water vial + peptide vial stoppers with isopropyl alcohol.
- 2 Draw the planned diluent volume into a 1 mL syringe.
- 3 Inject diluent slowly down the inside wall of the peptide vial — do NOT spray onto powder.
- 4 Swirl gently (do not shake) until fully dissolved. Solution should be clear.
- 5 Label vial with date reconstituted; refrigerate 2-8 °C.
- 6 Use within 30 days for most peptides (BPC-157 / TB-500 ~ 60 days at 4 °C).
▸ Overview TL;DR
Recombinant PTH 1-34 — first true bone-ANABOLIC drug, given as daily SC injection up to 2 years for severe osteoporosis. Counterintuitive mechanism: continuous PTH dissolves bone, but pulsed daily PTH builds it. NOT-RELEVANT for Dylan (20, peak BMD); document as reference for older-athlete fracture context and for the related compound abaloparatide.
▸ Mechanism of action
Teriparatide is the biologically active 1-34 amino acid fragment of human parathyroid hormone (PTH), produced via recombinant E. coli expression. It binds the same PTH/PTHrP type 1 receptor (PTH1R) as endogenous PTH on osteoblasts and renal tubule cells.
The core paradox: Continuous elevated PTH (e.g., primary hyperparathyroidism) is profoundly catabolic to bone — it stimulates RANKL on osteoblasts, drives osteoclast activation, and produces net bone loss with hypercalcemia. Brief daily pulses do the opposite. The mechanism is thought to be:
- Once-daily SC injection produces a short PTH spike (peak ~30 min, gone by ~3 hr)
- Brief PTH1R activation on osteoblast lineage cells preferentially upregulates anabolic signaling (Runx2, Wnt/β-catenin via Sost suppression, IGF-1) before catabolic RANKL expression catches up
- Net effect: increased osteoblast number, decreased osteoblast apoptosis, modeling-based bone formation, and improved trabecular microarchitecture
- Osteoclast activation does still occur — bone formation outpaces resorption only for ~12-24 months ("anabolic window") before equilibrium re-establishes; this is why duration is capped
Teriparatide preferentially builds trabecular (vertebral) bone, with weaker but real effects on cortical bone (hip, forearm).
▸Molecular information Peptide
▸ Pharmacokinetics Approximate
Approximate decay curve drawn from the half-life mention(s) in the source notes. Real PK data not yet ingested per compound.
▸Quality indicators6 checks
▸ What to expect Generic
- 1Week 1Injection / administration protocol established. Tolerability check.
- 2Week 2-4Early onset of effect — subtle in most users, noticeable in responders.
- 3Week 4-8Peak benefit window for most peptide cycles.
- 4Week 8+Cycle decision point: continue, taper, or break.
▸ Side effects + safety
Common (>10%): Nausea, arthralgia, mild injection-site reactions, asymptomatic mild hypercalcemia (transient peak 4-6 hr post-dose)
Less common (1-10%): Orthostatic hypotension (first doses), leg cramps, dizziness, headache, hyperuricemia, hypercalciuria
Rare-serious (<1%):
- Symptomatic hypercalcemia — especially with concurrent vitamin D, calcium supplements, thiazide diuretics
- Digoxin sensitization — hypercalcemia potentiates digoxin → arrhythmia risk
- Osteosarcoma (BLACK BOX historically) — Fischer rats given high doses for most of their lifespan developed osteosarcoma at high rates. Human signal: post-marketing surveillance over ~20 years (Forteo Patient Registry, US-only, ~76,000 patients tracked) detected NO excess osteosarcoma above baseline incidence. The 2-year lifetime cap and black box warning were both removed/loosened by FDA in 2020 based on this reassuring human data — the cap was restated as "use longer than 2 years only when continued treatment justified."
- Allergic reactions (rare, including anaphylaxis case reports)
Specific watch periods:
- First 4-6 doses: orthostatic events
- Months 1-3: serum calcium check (immediate baseline + ~1 month + then PRN)
- 24-hour urine calcium baseline if hypercalciuria history
- Annual DXA to verify gain and decision-point for sequencing
Contraindications (label):
- Prior skeletal radiation
- Pre-existing hypercalcemia (any cause)
- Paget's disease of bone
- Unexplained alkaline phosphatase elevation
- Open epiphyses (pediatric — bone still growing) ← This is one reason teriparatide is not used in young adults in the post-epiphyseal-fusion 18-25 window even off-label; the regulatory caution about "active bone growth" lingers.
- Bone metastases or skeletal malignancies, or prior radiation to skeleton
▸Interactions6 compounds
- denosumabSynergistic(concurrent) — DATA trial showed additive BMD effect; emerging combination strategy in highest-risk patients
- bisphosphonate / denosumabSynergistic(sequential, post-teriparatide) — locks in gains, considered standard of care for severe osteoporosis
- vitamin D + calciumSynergisticrequired co-administration (insufficient calcium/D blunts response and increases fracture risk despite BMD gain). Target 25(OH)D ≥30 ng/mL, calcium 1000-1200…
- digoxinAvoidhypercalcemia from teriparatide can sensitize myocardium → arrhythmia
- thiazide diureticsAvoidadditive hypercalcemia risk (HCTZ reduces urinary calcium excretion)
- bisphosphonates concurrentlyAvoid(alendronate + teriparatide simultaneously) — the older Black 2003 NEJM data suggested alendronate blunted teriparatide response when given together; this wa…
▸References8 sources
Neer et al. 2001 NEJM — Fracture Prevention Trial
2001pivotal RCT, n=1637, 65% vertebral / 53% non-vertebral fracture reduction
Saag et al. 2007 NEJM — Glucocorticoid-induced osteoporosis
2007teriparatide superior to alendronate
Kendler et al. 2018 Lancet — VERO trial (vs risedronate)
201832137-2) — head-to-head with risedronate, 56% vertebral fracture reduction
Miller et al. 2016 JAMA — ACTIVE trial (abaloparatide vs teriparatide)
2016class comparison
Tsai et al. 2013 Lancet — DATA trial (concurrent denosumab+teriparatide)
201360856-9) — combination strategy
FDA 2020 label update removing 2-year cap
2020duration restriction loosened based on post-marketing data
Forteo prescribing information (current)
full label
Black et al. 2003 NEJM — alendronate + teriparatide combination
2003basis for "anabolic before antiresorptive" sequencing rule