Most osteoporosis medications work by slowing bone breakdown — they preserve what you have. A different category, called anabolic agents, actually builds new bone. Teriparatide (Forteo, Osnuvo) and romosozumab (Evenity) are the two available in Canada, and they're used when bone building, not just preservation, is the goal.
Understanding which type of medication you're on — or being offered — starts with this distinction. Antiresorptive medications slow the cells (osteoclasts) that break down bone. Anabolic medications stimulate the cells (osteoblasts) that build new bone.
| Category | Medications | Mechanism | Typical BMD Gain (Lumbar Spine) |
|---|---|---|---|
| Antiresorptive | Alendronate, risedronate, zoledronic acid (bisphosphonates); denosumab (Prolia) | Slow bone breakdown | 2–4% over 2–3 years |
| Anabolic / Osteoanabolic | Teriparatide (Forteo, Osnuvo); romosozumab (Evenity) | Build new bone | 9–15% over 12–24 months |
For most people with osteoporosis, bisphosphonates are the right first-line treatment — they're well-studied, inexpensive, and broadly covered. Anabolic agents are reserved for severe osteoporosis where the priority is gaining bone mass, not just slowing loss.
Teriparatide is a synthetic fragment of parathyroid hormone (PTH 1-34). When given as a daily injection in small doses, it drives osteoblast activity and generates new bone — the opposite of what happens with chronic high PTH in hyperparathyroidism.
Teriparatide is a daily subcutaneous (under-the-skin) self-injection, typically in the thigh or abdomen. The treatment duration is capped at 24 months — that limit applies once in a lifetime, not once per brand.
Forteo is the original brand from Eli Lilly. Osnuvo is a Health Canada-approved biosimilar, introduced to provide a lower-cost alternative. The two are considered therapeutically equivalent.
Osnuvo is covered with Special Authority on most provincial formularies, including BC PharmaCare, Ontario's ODB program, and Alberta's Non-Group Benefits. Forteo (brand) is less often covered directly but may be accessible via private insurance or manufacturer support.
Eli Lilly offers a patient support program for Forteo. The Osnuvo manufacturer also has assistance pathways. If your provincial formulary rejects the initial Special Authority application, the decision can be appealed — ask your physician or pharmacist to assist with the appeal process.
In clinical trials, teriparatide produced lumbar spine BMD gains of approximately +9–13% over 24 months. This is substantially larger than what bisphosphonates achieve. Hip BMD gains are more modest (+3–6%), but fracture risk reduction is significant at both sites.
The most common side effect is dizziness or lightheadedness shortly after injection, especially with the first few doses. Inject lying down for the first week to reduce this risk — sit or stand slowly afterward. Other common effects include nausea, a metallic taste, and leg cramps.
The osteosarcoma question comes up often. Preclinical studies in rats showed increased bone tumour risk at very high doses over their full lifespan. This has not been observed in humans at therapeutic doses. Post-marketing surveillance of over 1.7 million patient-years has not demonstrated an increased osteosarcoma signal in humans. The 24-month lifetime limit exists as a precaution derived from those animal studies.
Your prescribing physician will review these before initiating teriparatide. A baseline serum calcium should be checked, and calcium and vitamin D intake should be adequate throughout treatment.
Romosozumab is a sclerostin inhibitor with a mechanism unlike any other osteoporosis medication. Sclerostin is a protein that normally suppresses bone formation. By blocking it, romosozumab simultaneously increases bone formation and decreases bone resorption — a dual anabolic and antiresorptive action.
Evenity is given as two subcutaneous injections once monthly for 12 months — administered by a healthcare provider, not self-injected at home. The course is one year only. After completing romosozumab, transition to antiresorptive therapy is required.
In the ARCH trial (Saag et al., NEJM 2017), romosozumab produced lumbar spine BMD gains of approximately +13% over 12 months. A 2025 JCEM comparison showed romosozumab achieved superior BMD gains at both spine and hip compared to teriparatide at 12 months, making it the strongest bone-building option available in Canada.
Romosozumab costs approximately $7,900–$8,500 per year in Canada. It is not listed as a benefit under BC PharmaCare as of early 2026, and coverage varies significantly by province. Most provincial public plans require Special Authority or do not list it at all.
Patients typically access Evenity through private drug insurance or the Amgen One-to-One patient support program. If you're in a province where it's not covered and you don't have private insurance, discuss the Amgen program directly with your physician's office.
Abaloparatide (brand name Tymlos in the US) is a PTH-related peptide analogue approved by the FDA and used in the United States. It is not approved by Health Canada and is not available in Canada. If you encounter US-based information about Tymlos, it does not apply to your treatment options.
Osteoporosis Canada guidelines identify specific criteria for anabolic therapy. These drugs are not first-line for all patients with osteoporosis — they're reserved for those with the highest fracture risk or those who have failed prior treatment.
Anabolic agents are generally indicated when one or more of the following applies:
See the DEXA scan guide for how T-scores and fracture risk are assessed, and osteoporosis medications overview for how these fit into the full treatment landscape.
The bone gains from anabolic therapy are real, but they depend on continued suppression of bone resorption to be maintained. After completing your 12-month romosozumab course or 24-month teriparatide course, your physician will transition you to a bisphosphonate (typically alendronate or zoledronic acid) or continue denosumab (Prolia).
If you're currently on Prolia and considering anabolic therapy, the transition sequence matters. See the stopping Prolia guide for why the order of operations is critical.
Special Authority applications for teriparatide (particularly Osnuvo) are submitted by your physician to your provincial drug plan. The typical required documentation includes your T-score, fracture history, and evidence of prior antiresorptive therapy (or contraindication to it).
If the initial application is denied, it can be appealed. A rejection at the first level does not mean the medication is unavailable — it means additional documentation or clinical justification may be needed. An osteoporosis specialist at an academic medical centre can often support these appeals.
For romosozumab, where provincial coverage is limited, the Amgen One-to-One program can substantially reduce out-of-pocket cost. Eligibility criteria apply and change over time — contact the program directly or have your clinic's support staff assist.
For information on the drug holidays that precede or follow anabolic therapy, see that dedicated guide.