Generic Cyproheptadine ( Cyproheptadine )

Cyproheptadine

Cyproheptadine is a first‑generation antihistamine with additional antiserotonergic and anticholinergic properties, indicated for the symptomatic relief of allergic rhinitis, allergic conjunctivitis, urticaria, and other histamine‑mediated dermatologic conditions. It works by competitively blocking H1 histamine receptors, thereby reducing itching, sneezing, rhinorrhea, and wheal formation. Its antiserotonergic activity also makes it useful in the management of migraine headaches and serotonin syndrome in selected cases, and it may stimulate appetite. Cyproheptadine is available only by prescription in Canada.

Usual adult dose: The usual dose is 4 mg taken orally three times daily. The dose may be adjusted based on response and tolerability; the maximum recommended dose is 0.5 mg/kg per day, up to a total of 32 mg per day in adults. The 4 mg tablet is the standard strength. Cyproheptadine may be taken with or without food; taking it with food or milk may reduce gastrointestinal upset. For elderly patients or those sensitive to anticholinergic effects, a lower starting dose of 4 mg twice daily is recommended. If a dose is missed, it should be taken as soon as remembered, but two doses should not be taken at the same time. Use in children is weight‑based and requires medical supervision.

Dosage form: Oral tablets: 4 mg (white to off‑white, round, flat‑faced, scored, often debossed with "CYP" or "4"). Available in bottles of 100 or 500 tablets. Cyproheptadine is also available as an oral syrup (2 mg/5 mL) for paediatric or elderly patients who have difficulty swallowing tablets.

Onset of action: Antihistaminic effects begin within 30 to 60 minutes after oral administration, with peak plasma concentrations at approximately 2 hours. Symptomatic relief of itching, sneezing, and rhinorrhea is usually apparent within the first hour. The appetite‑stimulating effect may take several days of regular use to become evident.

Duration of action: The clinical effect lasts approximately 4 to 6 hours, supporting three‑times‑daily dosing. The elimination half‑life of cyproheptadine is approximately 8 hours, but the duration of antihistaminic action is shorter than the half‑life because of distribution to tissues. The medication is typically given three times daily to maintain symptom control throughout the day.

Alcohol recommendation: Alcohol should be avoided or strictly limited during cyproheptadine therapy. Alcohol can potentiate the central nervous system depressant effects of cyproheptadine, including drowsiness, dizziness, and impaired coordination. Patients should not drive or operate hazardous machinery until they know how the combination affects them.

Most common side effects: Drowsiness, dizziness, dry mouth, blurred vision, constipation, and urinary retention. Drowsiness is common and may diminish with continued use, but patients should be cautioned about engaging in activities requiring mental alertness. Anticholinergic effects such as dry mouth and constipation can be managed with adequate hydration and dietary fibre. Cyproheptadine is contraindicated in patients with known hypersensitivity, narrow‑angle glaucoma, stenosing peptic ulcer, symptomatic prostatic hypertrophy, bladder neck obstruction, pyloroduodenal obstruction, and in patients receiving monoamine oxidase inhibitors (MAOIs). It should be used with caution in patients with asthma, hyperthyroidism, cardiovascular disease, or hypertension. Rarely, paradoxical excitation, hallucinations, or seizures may occur, particularly in children. Cyproheptadine is not recommended during pregnancy or breastfeeding unless clearly needed. In Canada, cyproheptadine is available only by prescription and should be used under medical supervision.

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Buy Generic Cyproheptadine (Cyproheptadine) without prescription in Canada

At our pharmacy, you can buy Cyproheptadine without a prescription, with discreet and anonymous packaging delivered within 5-14 days across Canada. Prednisone 5mg Tablet HSA/FSA Eligible.

What is Cyproheptadine?

Cyproheptadine is a first-generation antihistamine with a unique profile. It blocks histamine and serotonin receptors, which makes it useful for more than just allergies. It is prescribed for allergic conditions like hay fever, hives, and itchy skin. It is also used to stimulate appetite and promote weight gain in people who are underweight due to illness or poor nutrition. Because it blocks serotonin, it can help with certain types of headaches and has been used off-label for serotonin syndrome. The 4 mg tablet is the standard strength. It is taken two to three times daily, depending on the condition. The effect on itching and allergy symptoms begins within an hour, but the appetite-stimulating effect builds over several days of regular use. Cyproheptadine causes drowsiness, which is why it is also sometimes used as a mild sleep aid, though that is not its primary purpose. It is not a controlled substance and is not addictive. The drug is available as a generic and under the brand name Periactin.

Mechanism and Pharmacology

Cyproheptadine is an antagonist at histamine H1 receptors and serotonin 5-HT2 receptors. Blocking H1 receptors reduces the allergic response: itching, sneezing, runny nose, and hives. Blocking 5-HT2 receptors is what sets it apart from other antihistamines. Serotonin antagonism reduces appetite suppression and can stimulate the hunger centre in the hypothalamus. This is why it is used for weight gain. The same serotonin blockade makes it useful in treating serotonin syndrome, a potentially fatal condition caused by excess serotonin activity. Cyproheptadine also has mild anticholinergic effects, which contribute to dry mouth and drowsiness.

After oral administration, cyproheptadine is well absorbed, with peak plasma levels reached in about 2 to 3 hours. The half-life is approximately 8 hours, which supports dosing every 8 hours. The drug is metabolized in the liver, primarily by glucuronidation, and the metabolites are excreted in the urine. Because it crosses the blood-brain barrier easily, it causes significant sedation compared to second-generation antihistamines like loratadine or cetirizine. The anticholinergic properties also mean it can worsen glaucoma, urinary retention, and asthma, so it must be used cautiously in those conditions. In older adults, the sedative and anticholinergic effects are more pronounced. The 4 mg tablet is a standard dose; for children, the dose is lower and based on weight.

How to Use Cyproheptadine

The dose depends on the condition being treated. For allergies in adults, the usual dose is 4 mg two to three times daily. The maximum is 32 mg per day, though doses that high are rarely used. For appetite stimulation and weight gain, the dose is usually 2 to 4 mg three times daily before meals. For children, the dose is based on weight and age, and the tablet can be crushed and mixed with food if needed. Always follow your doctor's instructions. Do not exceed the recommended amount.

Take the tablet with a full glass of water. It can be taken with or without food. If it upsets your stomach, taking it with food may help. If you are using it for appetite, take it about 30 minutes before meals. If you miss a dose, take it as soon as you remember. If it is almost time for the next dose, skip the missed one and continue on your schedule. Do not double up. Because cyproheptadine causes drowsiness, the first dose is often taken at bedtime. If you are taking it multiple times daily, be aware that it can impair your ability to drive or operate machinery. Do not stop taking it suddenly if you have been using it for a long time, because rebound symptoms can occur, though withdrawal is not severe. Taper only under medical advice. Cyproheptadine is not for long-term use in allergies without a doctor's oversight.

Side Effects of Cyproheptadine

The most common side effect is drowsiness. This can be significant, especially in the first few days. Many people adapt over time, but some sedation often persists. Dry mouth, blurred vision, and constipation are anticholinergic effects. Sucking on sugar-free candy or chewing gum can help with dry mouth. Increased appetite and weight gain are desired effects for some, but can be problematic for others. Dizziness and lightheadedness can occur, especially when standing up quickly. Rise slowly. Nausea and stomach upset are possible but usually mild.

Less common but more serious side effects include confusion, hallucinations, and urinary retention, particularly in elderly patients. Cyproheptadine can worsen narrow-angle glaucoma and should be used with extreme caution in people with this condition. It can thicken bronchial secretions and should be avoided in people with asthma or COPD. It can also lower the seizure threshold in susceptible individuals. Allergic reactions to cyproheptadine itself are rare. If you develop a rash, swelling, or difficulty breathing, stop the drug and seek emergency care. In children, paradoxical excitation can occur instead of sedation, causing restlessness and irritability. If this happens, the dose may need to be reduced or the drug stopped.

High-Risk Groups (Elderly, Pregnancy)

Pregnancy. Cyproheptadine is pregnancy category B. Animal studies have not shown fetal harm, but there are no adequate human studies. It is generally considered safe for short-term use during pregnancy, especially for allergy symptoms, but it should be used only if clearly needed. It crosses the placenta, and the sedative effect can affect the newborn if used near delivery. Always discuss with your obstetrician before taking any medication during pregnancy. Breastfeeding. Cyproheptadine passes into breast milk in small amounts. It can cause drowsiness and poor feeding in the infant. The manufacturer recommends against using it while breastfeeding. If you need an antihistamine while nursing, a second-generation drug like loratadine is preferred. Discuss with your doctor.

Elderly patients are very sensitive to the sedative and anticholinergic effects of cyproheptadine. It is on the Beers list of potentially inappropriate medications for older adults because it can cause confusion, falls, constipation, and urinary retention. If used at all, the dose should be low, and the duration short. People with glaucoma, enlarged prostate, bowel obstruction, or myasthenia gravis should not use cyproheptadine. Those with asthma or COPD should avoid it because of the drying effect on bronchial secretions. Patients with liver impairment may need a lower dose because the drug is metabolized by the liver. A complete medication review is essential before starting, especially in older adults and those with multiple health conditions.

Interaction With Activities (Driving, Alcohol)

Cyproheptadine causes significant drowsiness and can impair your ability to drive or operate machinery. Do not drive until you know how the drug affects you. The sedation is usually worst in the first week, but it can persist. Alcohol greatly increases the drowsiness and dizziness caused by cyproheptadine. Avoid alcohol entirely while taking this medication. Even a single drink can make you dangerously sleepy. If you drink, do not drive. The combination also increases the risk of falls and confusion. Caffeine may help counteract mild drowsiness, but it is not a substitute for avoiding driving when impaired.

Drug Interactions

Cyproheptadine interacts with many central nervous system depressants. Alcohol, benzodiazepines, opioids, sleeping pills, and sedating antihistamines all add to the drowsiness. The combination can cause severe sedation and impaired coordination. Avoid these combinations if possible. Other anticholinergic drugs, including tricyclic antidepressants, antipsychotics, and bladder medications like oxybutynin, can cause additive dry mouth, constipation, urinary retention, and confusion. This is a particular risk in elderly patients. Monoamine oxidase inhibitors (MAOIs) can prolong and intensify the effects of cyproheptadine. The combination should be avoided. Cyproheptadine can reduce the effectiveness of selective serotonin reuptake inhibitors (SSRIs) by blocking serotonin receptors, so it is sometimes used to treat sexual side effects from those drugs, but this should only be done under medical supervision. It can also interfere with the action of certain migraine medications. Always tell your doctor and pharmacist about all medications and supplements you take before starting cyproheptadine.

Alternative Options

For allergies, second-generation antihistamines like cetirizine, loratadine, and fexofenadine are preferred for most people because they cause little or no drowsiness and are taken once daily. Cyproheptadine is reserved for cases where its additional serotonin-blocking or appetite-stimulating effects are needed. For itching, topical antihistamines or corticosteroids may be used. For appetite stimulation and weight gain, other options include megestrol acetate, dronabinol, or mirtazapine, though each has its own risks. For children with poor weight gain, cyproheptadine is commonly used and is generally well tolerated. For allergic rhinitis, nasal steroid sprays like budesonide or fluticasone are first-line. The choice depends on the specific symptoms, the patient's age, and the need for sedation. Cyproheptadine occupies a niche for those who need an antihistamine that also stimulates appetite or blocks serotonin.

INN, Brand Names, and Classification in Canada

INN (International Nonproprietary Name): Cyproheptadine hydrochloride
Available brand names in Canada: Periactin, and generic cyproheptadine
ATC code: R06AX02
Forms and strengths: Tablets 4 mg. Also available as an oral liquid in some formulations.
Manufacturers: Various generic manufacturers including Apotex Inc., Teva Canada Limited, and Sandoz Canada Inc. The brand Periactin was originally marketed by Merck.
Registration status in Canada: Registered
Classification: Prescription (Rx)

Frequently Asked Questions

How fast does cyproheptadine work for allergies?
It starts to relieve itching, sneezing, and runny nose within about an hour of taking the tablet. The effect lasts about 6 to 8 hours, which is why it is taken two to three times daily. For appetite stimulation, the effect builds over several days.

Will cyproheptadine make me gain weight?
Yes, weight gain is a common side effect, which is why the drug is used off-label for people who need to gain weight. It increases appetite and reduces the feeling of fullness. If you do not want to gain weight, talk to your doctor about a different antihistamine.

Can I take cyproheptadine to help me sleep?
It causes drowsiness and is sometimes used off-label for sleep, but it is not a first-line sleep aid. The anticholinergic effects and morning hangover make it less desirable than other options. If you have chronic insomnia, see your doctor about safer treatments.

Is cyproheptadine safe for children?
Yes, it is commonly prescribed for children, especially for appetite stimulation and allergies. The dose is based on weight. It can cause drowsiness, which may affect school performance. In some children, it causes excitation instead of sedation. Always follow the pediatrician's instructions.

Can I stop cyproheptadine suddenly?
Stopping suddenly after long-term use can cause rebound itching or appetite loss, but severe withdrawal is uncommon. It is best to taper under a doctor's advice if you have been taking it regularly for weeks or months. For short-term use, you can simply stop.

Delivery Information Across Canada

We ship Cyproheptadine to all provinces and territories. Delivery times vary depending on how remote your location is:

  • Ontario (Toronto, Ottawa, Mississauga): 5 to 7 days
  • Quebec (Montreal, Quebec City, Laval): 5 to 7 days
  • British Columbia (Vancouver, Victoria, Burnaby): 5 to 9 days
  • Alberta (Calgary, Edmonton, Red Deer): 5 to 9 days
  • Manitoba (Winnipeg, Brandon): 5 to 9 days
  • Saskatchewan (Saskatoon, Regina): 5 to 9 days
  • Nova Scotia (Halifax, Sydney): 5 to 9 days
  • New Brunswick (Moncton, Fredericton): 5 to 9 days
  • Newfoundland and Labrador (St. John's, Corner Brook): 7 to 14 days
  • Prince Edward Island (Charlottetown): 7 to 14 days
  • Yukon, Northwest Territories, Nunavut: 7 to 14 days

All shipments are packed discreetly with no branding or indication of contents on the outside.

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