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Cyproheptadine

Antihistamine

Brand names:

Periactin®

Often used for:

Symptoms associated with allergies, hay fever, colds, and allergic reactions; may be used to improve appetite and promote weight gain

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What is cyproheptadine?

Cyproheptadine is an antihistamine. This type of medicine acts to block the activity of the histamine, a substance that causes allergy symptoms.

Cyproheptadine can be used to treat a variety of symptoms including:

  • Allergy and cold symptoms such as irritated and itchy eyes, sneezing, and runny nose
  • Itching and hives
  • Allergic reactions such as rash, itching, swelling
  • Movement problems
  • Migraine headaches
  • Vomiting

Cyproheptadine may also be used to stimulate appetite and promote weight gain.

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May be taken as a tablet by mouth

 
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May be taken as a liquid by mouth

 
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Possible cyproheptadine side effects

  • Drowsiness or dizziness
  • Dry mouth, nose, or throat
  • Increased appetite
  • Weight gain
  • Feeling nervous, excitable, or restless
  • Sun sensitivity
  • Fatigue or weakness
  • Nausea and vomiting
  • Diarrhea
  • Constipation
  • Abdominal pain
  • Headache
  • Increased congestion of the nose or chest
  • Blurry vision

Not all patients who take cyproheptadine will experience these side effects. Common side effects are in bold, but there may be others. Please report all suspected side effects to your doctor or pharmacist.

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Tips for families

Be sure to discuss these and other recommendations with your doctor or pharmacist.

  • Be careful when using more than one cold or allergy medicine at the same time. These products may have similar ingredients, and using them together could cause an overdose. Read the label carefully, and discuss any questions with a doctor or pharmacist.
  • Patients should protect their skin from the sun while taking this medicine.
  • Patients should avoid drinking alcohol while on this medicine.
  • Patients should tell their doctor if they are pregnant or breastfeeding.

Cyproheptadine at home:

  • Do not take more often or in greater amounts than recommended.
  • Cyproheptadine may be taken with or without food. Take with food if stomach upset occurs.
  • This medicine may make you dizzy or drowsy. Do not drive or do anything that could be dangerous until you see how this medicine affects you.
  • For liquid cyproheptadine (oral syrup), use the measuring device that comes with the medicine.
  • Give a missed dose as soon as possible. If it is near the time for the next dose, skip the dose. Do not give 2 doses at the same time.
  • Store cyproheptadine at room temperature. Cyproheptadine syrup should be protected from light.
  • Do not use the medicine past the expiration date.
  • Follow instructions for safe storage and disposal.

Learn More About Cyproheptadine

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Always check the medication label. Many medicines look the same. Do not take any new medicine, including over-the counter medicines or supplements, without checking with your doctor or pharmacist. Talk to your doctor or pharmacist about what to do in the case of a missed dose, allergic reaction, or medical emergency. 

This information is not intended to be a complete guide and is not a substitute for talking with your provider. Medicine names, appearance, formulas, or availability may vary by clinic location. Always follow the instructions given by your care team.