Cyproheptadine hydrochloride

Brand names: Periactin

Why is Cyproheptadine hydrochloride prescribed?

Periactin is an antihistamine given to help relieve cold- and allergy-related symptoms such as hay fever, nasal inflammation, stuffy nose, red and inflamed eyes, hives, and swelling. Periactin may also be given after epinephrine to help treat anaphylaxis, a life-threatening allergic reaction.

Some doctors prescribe Periactin to treat cluster headache and to stimulate appetite in underweight people.

Most important fact about Cyproheptadine hydrochloride

Like other antihistamines, Periactin may make you feel sleepy and sluggish. However, some people, particularly children, may have the opposite reaction and become excited.

How should you take Cyproheptadine hydrochloride?

Take Periactin exactly as prescribed by your doctor.

  • If you miss a dose...Take it as soon as you remember. If it is almost time for your next dose, skip the one you missed and go back to your regular schedule. Do not take 2 doses at once.
  • Storage instructions...Store at room temperature in a tightly closed container.

What side effects may occur?

Side effects cannot be anticipated. If any develop or change in intensity, tell your doctor immediately. Only your doctor can determine whether it is safe for you to continue taking Periactin.

  • Side effects may include:Anaphylaxis (life-threatening allergic reaction), anemia, appetite loss, chest congestion or tightness, chills, confusion, constipation, convulsions, diarrhea, difficulty urinating, dizziness, dry mouth, nose, or throat, earlier-than-expected menstrual period, exaggerated feeling of well-being, excessive perspiration, excitement, faintness, fatigue, fluttery or throbbing heartbeat, frequent urination, hallucinations, headache, hives, hysteria, inability to urinate, increased appetite and weight gain, insomnia, irritability, lack of coordination, light sensitivity, liver problems, low blood pressure, nausea, nervousness, rapid heartbeat, rash and swelling, restlessness, ringing in the ears, sleepiness, stomach pain, stuffy nose, tingling or pins and needles, tremor, vertigo, vision problems (double vision, blurred vision), vomiting, weight gain, wheezing, yellow eyes and skin

Older people, in particular, are likely to become dizzy or drowsy, or develop low blood pressure in response to Periactin.

Why should Cyproheptadine hydrochloride not be prescribed?

Do not take Periactin if you are sensitive to it, or have ever had an allergic reaction to it or to a similar antihistamine.

Do not take Periactin if you are taking an antidepressant drug known as an MAO inhibitor.

Do not take Periactin if you have the eye condition called angle-closure glaucoma, a peptic ulcer, an enlarged prostate, obstruction of the neck of the bladder, or obstruction of the outlet of the stomach.

Newborn or premature infants should not be given Cyproheptadine hydrochloride, nor should it be used by women who are breastfeeding an infant.

The elderly and those in a weakened condition should not take Cyproheptadine hydrochloride.

Special warnings about Cyproheptadine hydrochloride

Like other antihistamines, Periactin may make you drowsy or impair your coordination. Be very careful about driving, climbing, or operating machinery, or doing hazardous tasks until you know how you react to Cyproheptadine hydrochloride.

Be cautious about taking Periactin if you have bronchial asthma, the eye condition called glaucoma, an overactive thyroid gland, high blood pressure, heart disease, or circulatory problems.

Possible food and drug interactions when taking Cyproheptadine hydrochloride

Avoid alcoholic beverages while taking Periactin.

If Periactin is taken with certain other drugs, the effects of either could be increased, decreased, or altered. It is especially important to check with your doctor before combining Periactin with the following:

Antidepressant drugs classified as MAO inhibitorsSedativesTranquilizers

Special information if you are pregnant or breastfeeding

Because of possible harm to the unborn baby, Periactin should not be used during pregnancy unless it is clearly needed. Periactin should not be taken by a woman who is breastfeeding. If you have just given birth, you will need to choose between breastfeeding and taking Periactin.

Recommended dosage for Cyproheptadine hydrochloride


The usual initial dose is 4 milligrams (1 tablet) 3 times daily. Dosage may range from 4 to 20 milligrams a day, but most people will take between 12 and 16 milligrams. Some may need as much as 32 milligrams a day. If you are over 65, the doctor will probably keep the dosage relatively low.


Ages 2 to 6 Years

The usual dose is 2 milligrams (one-half tablet) 2 or 3 times a day; your doctor may adjust the dose if necessary. A child this age should not take more than 12 milligrams a day.

Ages 7 to 14 Years

The usual dose is 4 milligrams (1 tablet) 2 or 3 times a day; your doctor may adjust the dose if needed. A child this age should not take more than 16 milligrams a day.


Any drug taken in excess may have serious consequences. An overdose of Periactin can be fatal. If you suspect an overdose, seek medical attention immediately.

  • Symptoms of Periactin overdose may include:Dilated pupils, dry mouth, extreme excitement and agitation, fever, flushing, stomach or bowel distress, stupor or coma

Overdosage in children may produce hallucinations and convulsions.

  • Cyproheptadine Prescribing Information (FDA)
  • cyproheptadine Concise Consumer Information (Cerner Multum)
  • Cyproheptadine MedFacts Consumer Leaflet (Wolters Kluwer)