TL;DR
- Calan is a brand name for norethisterone, a synthetic progesterone used for menstrual disorders and contraception.
- Typical adult dose for hormone therapy is 5mg daily; for contraception it’s 0.35mg in a combined pill.
- Common side effects include nausea, breast tenderness, and mood changes; serious risks are rare but include blood clots.
- Take Calan with food, at the same time each day, and avoid it if you’re pregnant, smoke heavily, or have certain liver conditions.
- Always discuss with a GP or pharmacist before starting, especially if you’re on other meds.
What is Calan and How Does It Work?
Calan is the trade name for norethisterone, a synthetic form of the natural hormone progesterone. It mimics the body’s own progesterone to regulate the menstrual cycle, thin the uterine lining, and prevent ovulation when combined with estrogen. The drug belongs to the class of progestins and has been on the market in the UK since the 1970s.
When you take Calan, the progestin binds to progesterone receptors in the uterus and brain. This signals the body to stay in the luteal phase, which either postpones a period (useful for delaying menstruation) or stabilises irregular cycles. In combined oral contraceptives, norethisterone works alongside estrogen to suppress the release of follicle‑stimulating hormone (FSH) and luteinising hormone (LH), stopping the ovary from releasing an egg.
Because it’s a hormone, timing and consistency matter. Skipping doses or taking it at irregular times can cause breakthrough bleeding or reduce effectiveness.
Approved Uses and Typical Dosage Regimens
Calan is prescribed for several distinct indications. The dosage varies depending on the reason you’re taking it.
- Menstrual Cycle Management: 5mg taken daily for up to 10days to delay a period or treat irregular bleeding.
- Endometriosis Treatment: 5mg daily for 3‑6months, sometimes followed by a drug‑free interval.
- Contraception: As part of a combined pill (e.g., 0.35mg norestisterone + 0.02mg ethinylestradiol) taken for 21 days followed by a 7‑day break.
To maximise benefits and minimise side‑effects, follow these practical rules:
- Start the tablet at the same clock time each day - morning is often easiest.
- If you miss a dose, take it as soon as you remember unless it’s within 12hours of the next dose; then skip the missed one to avoid double‑dosing.
- Do not crush or chew the tablet; swallow whole with water.
- Store below 30°C, away from moisture and direct sunlight.
Always double‑check the specific regimen your doctor gave you - the above are common, not universal.
Side Effects, Risks and Who Should Avoid Calan
Like any hormone, Calan can cause unwanted effects. Most are mild and resolve within a few weeks, but a few require medical attention.
| Side Effect | Frequency | Typical Onset |
|---|---|---|
| Nausea / vomiting | Common (1‑10%) | First few days |
| Breast tenderness | Common (1‑10%) | Within 1‑2 weeks |
| Headache | Common (1‑10%) | First week |
| Mood swings / depression | Uncommon (0.1‑1%) | 2‑4 weeks |
| Weight gain | Uncommon (0.1‑1%) | 1‑2 months |
| Blood clot (DVT/PE) | Rare (<0.1%) | Variable |
| Liver enzyme elevation | Rare (<0.1%) | After 3+ months |
Serious complications such as deep‑vein thrombosis (DVT) or pulmonary embolism are extremely rare but more likely if you smoke, are over 35, or have a history of clotting disorders. If you notice sudden leg pain, swelling, or shortness of breath, seek emergency care.
People who should NOT take Calan include:
- Pregnant or breastfeeding women (unless prescribed for a specific condition by a specialist).
- Those with active liver disease, severe hypertension, or known breast cancer.
- Heavy smokers (>15 cigarettes/day) over the age of 35.
- Anyone taking strong enzyme‑inducing drugs (e.g., certain antiepileptics) without medical supervision, as they can lower Calan’s effectiveness.
Before starting, always provide a full medication list to your GP - interactions with antibiotics, antifungals, or herbal supplements can be significant.
Practical Tips, FAQs and What to Do If Things Go Wrong
Below are the most common questions people ask after the prescription is written.
- Can I take Calan to skip my period for a vacation? Yes, a 5mg daily dose for up to 10 days can reliably delay bleeding. Start the tablet 2‑3 days before the expected period and continue until you’re ready to resume a normal cycle.
- Will Calan affect my fertility? Short‑term use does not cause permanent infertility. Ovulation typically returns within one to two cycles after stopping.
- Is it safe to combine Calan with hormonal IUDs? Generally not recommended without specialist advice because the cumulative progestin load can increase side‑effects.
- What should I do if I miss a dose? If it’s less than 12hours late, take it immediately and continue as normal. If more than 12hours, skip the missed dose and resume your regular schedule - don’t double‑dose.
- Can I take Calan while on a low‑carb diet? Diet does not affect the drug’s absorption, but drastic weight loss may alter hormone levels, so keep your doctor informed.
**Troubleshooting checklist**:
- Unexpected breakthrough bleeding? Check if you missed a dose or started a new medication that speeds up metabolism.
- Severe mood changes? Discuss with your GP; a lower dose or alternative progestin may be needed.
- Weight gain after a few months? Review your overall diet and activity - hormones can cause fluid retention, not fat.
Remember, the key to a smooth experience is consistency, open communication with your prescriber, and prompt reporting of any unusual symptoms.
Bottom Line - Is Calan Right for You?
Calan is a versatile, well‑studied progestin that can help manage periods, treat endometriosis, and serve as a component of contraception. Its safety profile is solid for most healthy adults, but it demands caution in smokers, older women, and those with liver or clotting issues.
If you need a reliable way to delay a period for a special event, or you’re dealing with painful menstrual irregularities, a short course of Calan is often the simplest solution. For long‑term contraception, consider the combined pill or discuss intra‑uterine options with your clinician.
Always have a clear conversation with your GP or pharmacist - they can tailor the dose, monitor labs if needed, and switch you to another hormone if side‑effects become bothersome. With the right guidance, Calan can be a safe, effective tool in your reproductive‑health toolbox.
