TL;DR
- Calcort is a synthetic salmon calcitonin used for osteoporosis, Paget’s disease and high blood calcium.
- Available as nasal spray (200IU) and injection (100IU); dosing varies by condition.
- Common side effects include nasal irritation, nausea and flushing; serious reactions are rare.
- Do not use if pregnant, nursing or allergic to any ingredient; always discuss kidney or thyroid issues with a doctor.
- Stay hydrated, avoid abrupt discontinuation, and keep a medication record for interactions.
What Is Calcort and How Does It Work?
Calcort is the brand name for synthetic salmon calcitonin, a hormone that helps regulate calcium levels in the body. While the human version of calcitonin is produced in the thyroid, the salmon form is more potent and longer‑acting, making it useful as a prescription drug.
When you take Calcort, it binds to calcitonin receptors on bone cells, signaling them to slow down bone breakdown (resorption). At the same time, it tells the kidneys to excrete more calcium, helping lower blood calcium levels. This dual action is why doctors prescribe it for three main reasons:
- Preventing further bone loss in post‑menopausal osteoporosis.
- Managing Paget’s disease of bone, where bone remodeling goes haywire.
- Treating acute hypercalcaemia (dangerously high calcium) when other measures are insufficient.
Because it mimics a natural hormone, Calcort is generally well‑tolerated, but it isn’t a cure‑all. It works best when combined with calcium‑ and vitamin‑D supplementation, weight‑bearing exercise, and other osteoporosis drugs if needed.
Approved Uses and Who Should Take It
Regulatory agencies such as the UK MHRA and the US FDA have cleared Calcort for the following indications:
- Post‑menopausal osteoporosis: Women over 50 with a confirmed diagnosis and a high risk of fractures.
- Paget’s disease of bone: Adults with abnormal bone turnover causing pain, deformities, or elevated alkaline phosphatase.
- Acute hypercalcaemia: Typically in cancer patients where calcium spikes dangerously high.
Who should avoid it?
- Pregnant or breastfeeding women - safety data are lacking.
- Anyone with a known allergy to salmon proteins or any component of the nasal spray or injectable form.
- Patients with severe renal impairment need close monitoring, as calcium handling is already compromised.
If you fall into one of the approved groups, a doctor will weigh Calcort against other options like bisphosphonates, denosumab, or selective estrogen receptor modulators (SERMs). The decision often hinges on personal tolerance, cost, and convenience.
Dosage Guidelines and Administration
Calcort comes in two formats, each with its own dosing schedule. Below is a quick reference:
Formulation | Strength | Typical Dose | Frequency | Administration Notes |
---|---|---|---|---|
Nasal spray | 200IU per puff | 1 puff (200IU) | Once daily | Insert tip into one nostril, inhale gently. Do not share device. |
Injection | 100IU/0.5mL | 100IU | Every 3-7 days (depends on condition) | Subcutaneous injection, preferably in the abdomen. Rotate sites. |
For osteoporosis, the most common regimen is one nasal spray puff each morning. If you can’t tolerate the spray-because of chronic sinus issues, for example-the doctor may switch you to the injection, given once a week.
In hypercalcaemia, the dosage is more aggressive: a single 200IU nasal dose followed by repeat doses every 12hours until calcium levels normalize.
Key tips to remember:
- Always use the device that comes with a sealed tip; once opened, the spray loses potency after 30 days.
- If you miss a dose, take it as soon as you remember, unless it’s within 12hours of the next scheduled dose-then skip the missed one.
- Store the nasal spray at room temperature, away from direct sunlight. Refrigerate the injectable vials if not used within a month.

Side Effects, Interactions, and Safety Tips
Most people experience only mild, transient side effects. The most frequently reported issues are:
- Nasal irritation, runny nose, or sneezing (spray only).
- Nausea, vomiting, or mild abdominal cramps.
- Flushing or a warm sensation on the face.
- Transient low calcium (hypocalcaemia) if you have normal baseline levels.
Serious but rare reactions include:
- Allergic rash or angioedema.
- Severe hypocalcaemia, especially in patients on high‑dose vitamin D supplements.
- Antibody formation that reduces the drug’s effectiveness after prolonged use (observed after >2years).
Potential drug interactions:
- Calcium channel blockers - may modestly increase the risk of low calcium.
- Thyroid hormone replacement (levothyroxine) - monitor thyroid function tests because calcitonin can slightly affect thyroid hormone metabolism.
- Other osteoporosis agents (bisphosphonates, denosumab) - no direct contraindication, but overlapping mechanisms can raise the chance of low calcium.
Safety checklist before starting Calcort:
- Confirm you’re not pregnant, nursing, or allergic to salmon proteins.
- Get a baseline calcium, phosphate, and alkaline phosphatase lab panel.
- Review current supplements-especially calcium and vitaminD-to avoid excess.
- Discuss any history of kidney stones or renal disease with your prescriber.
- Keep a written record of the device’s expiration date and any symptoms you notice.
If you experience any of the serious side effects listed above, seek medical attention right away. For mild issues, contact your pharmacist; they can suggest saline nasal rinses or anti‑nausea strategies.
Mini‑FAQ
Q: How quickly does Calcort start working?
A: For osteoporosis, noticeable bone‑density improvements appear after 6-12months of consistent use. In hypercalcaemia, calcium levels often drop within 4-6hours of the first dose.
Q: Can I switch between nasal and injectable forms?
A: Yes, but do it under medical supervision. The dosing interval changes, and you’ll need a brief overlap period to maintain steady hormone levels.
Q: Is Calcort safe for long‑term use?
A: Studies up to 2years show a stable safety profile, but antibody development can reduce effectiveness after that. Your doctor may reassess the need for continuation annually.
Q: Does Calcort interact with over‑the‑counter pain relievers?
A: Ibuprofen and acetaminophen are generally safe, but high‑dose aspirin can irritate the nasal mucosa and should be avoided with the spray.
Q: What should I do if I forget a dose?
A: Take it as soon as you remember unless it’s within 12hours of the next scheduled dose; then skip the missed one and continue as normal.
Next Steps & Troubleshooting
If you’re considering Calcort, schedule a consultation with your GP or an endocrinologist. Bring a list of current meds, supplements, and any recent lab results. After you start:
- Monitor calcium levels at 1‑month, 3‑month, and 6‑month intervals.
- Keep a symptom diary-note any nasal discomfort, nausea, or unusual bruising.
- If you notice persistent side effects, ask about rotating to the injectable form or trying an alternative osteoporosis drug.
- Should you need to stop abruptly (e.g., surgery), discuss a tapering plan to avoid rebound bone loss.
Remember, Calcort is just one tool in a broader bone‑health strategy. Pair it with a balanced diet, regular weight‑bearing exercise, and routine bone‑density scans for the best outcome.