Periactin (CYPROHEPTADINE) is a piperidine antihistamine. Unlike other antihistamines, this drug also antagonizes serotonin receptors. This action makes Cyproheptadine useful in conditions such as vascular headache and anorexia. Cyproheptadine does not prevent the release of histamine but rather competes with free histamine for binding at HA-receptor sites. Cyproheptadine competitively antagonizes the effects of histamine on HA-receptors in the GI tract, uterus, large blood vessels, and bronchial smooth muscle. Most antihistamines possess significant anticholinergic properties, but Cyproheptadine exerts only weak anticholinergic actions. Blockade of central muscarinic receptors appears to account for Cyproheptadine's antiemetic effects, although the exact mechanism is unknown. Cyproheptadine also competes with serotonin at receptor sites in smooth muscle in the intestines and other locations. Antagonism of serotonin on the appetite center of the hypothalamus may account for Cyproheptadine's ability to stimulate appetite. Cyproheptadine also has been used to counter vascular headaches, which many believe are caused by changes in serotonin activity, however it is unclear how Cyproheptadine exerts a beneficial effect on this condition. For treatment of perennial and seasonal allergic rhinitis, vasomotor rhinitis, allergic conjunctivitis due to inhalant allergens and foods, mild uncomplicated allergic skin manifestations of urticaria and angioedema, amelioration of allergic reactions to blood or plasma, cold urticaria, dermatographism, and as therapy for anaphylactic reactions adjunctive to epinephrine.

Common uses

Cyproheptadine relieves red, irritated, itchy, watery eyes; sneezing; and runny nose caused by allergies, irritants in the air, and hay fever. It may also be used to relieve the itching of allergic skin conditions, and to treat hives, including hives caused by exposure to cold temperatures and by rubbing the skin. Cyproheptadine is also sometimes used to treat allergic reactions in people who have received blood products as part of medical treatment and to treat life-threatening allergic reactions after the symptoms have been brought under control with other medications. Cyproheptadine should not be used to treat children younger than 2 years of age because it may cause serious or life-threatening side effects in young children. Cyproheptadine should be used carefully in children 2-11 years of age. Cyproheptadine will help relieve symptoms but will not treat the cause of symptoms or speed recovery. Cyproheptadine should not be used to cause sleepiness in children. Cyproheptadine is in a class of medications called antihistamines. It works by blocking the action of histamine, a substance in the body that causes allergic symptoms.

Before using

Your doctor need to know if you have any of these conditions:
•asthma or chronic obstructive lung disease (COPD)
•glaucoma
•high blood pressure or heart disease
•liver disease
•other chronic illness
•prostate disease
•pain or difficulty passing urine
•ulcers or other stomach problems
•pregnant or trying to get pregnant
•breast-feeding


Directions

Take cyproheptadine exactly as directed by your doctor. If you do not understand these directions, ask your pharmacist, nurse, or doctor to explain them to you.
Take each dose with a full glass of water.
Cyproheptadine can be taken with or without food.
To ensure that you get a correct dose, measure the syrup form of cyproheptadine with a special dose-measuring spoon or cup, not with a regular tablespoon. If you do not have a dose-measuring device, ask your pharmacist where you can get one.
Never take more of this medication than is prescribed for you. The maximum amount of cyproheptadine that you should take in 1 day is 32 mg.

Cautions

Use caution when driving, operating machinery, or performing other hazardous activities. Cyproheptadine may cause dizziness or drowsiness. If you experience dizziness or drowsiness, avoid these activities. Use alcohol cautiously. Alcohol may increase drowsiness and dizziness while you are taking cyproheptadine.

Possible side effects

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.
• More common 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.

If you take too much

Seek emergency medical attention.
Symptoms of a cyproheptadine overdose include extreme sleepiness, confusion, weakness, ringing in the ears, blurred vision, large pupils, dry mouth, flushing, fever, shaking, insomnia, hallucinations, and possibly seizures.
Overdosage in children may produce hallucinations and convulsions.

Additional information

Periactin is to be used only by the patient for whom it is prescribed. Do not share it with other people.
If your symptoms do not improve or if they become worse, check with your doctor.

Drug interactions

There may be an increase in sedation when cyproheptadine is taken with alcohol or other sedating medicines such as anti-anxiety medcines, hypnotics, sedatives or tranquillisers).

Monoamine oxidase inhibitor antidepressants (such as phenelzine) prolong and intensify the anti-cholinergic effects of antihistamines, such as, dry mouth, blurred vision and constipation.
MAO inhibitors prolong and intensify the anticholinergic effects of antihistamines. Antihistamines may have additive effects with alcohol and other CNS depressants, e.g., hypnotics, sedatives, tranquilizers, antianxiety agents.