Phamactin (Cyproheptadine hydrochloride)

Cyproheptadine hydrochloride, commonly known as Cyprodine or Phamactin, is an antihistamine medication used to relieve symptoms of allergies such as sneezing, itching, and watery eyes. It is also used to stimulate appetite and promote weight gain in people who have difficulty gaining weight due to medical conditions such as anorexia nervosa or cancer. Cyproheptadine works by blocking the action of histamine, a chemical produced by the body in response to allergens.

Cyproheptadine has potent antihistaminic and serotonin antagonist properties with anticholinergic, sedative and calcium-channel blocking activity. Cyproheptadine is beneficial in Cushing’s syndrome due to serotonin antagonist activity.

Oral cyproheptadine is well absorbed, completely metabolized to quarternary ammonium glucuronide conjugate and excreted principally in urine as conjugates and faeces. Elimination is diminished in renal insufficiency.

Indications

Cyproheptadine hydrochloride syrup is indicated in treatment of acute and chronic allergies such as dermatitis, eczema, mild and local allergic reactions to insect bites, hay fever, seasonal rhinitis, allergic conjuctivitis due to inhalant allergens and foods, urticaria, angioneurotic oedema, anogenital pruritus of chickenpox. It may also be used in treatment and prophylaxis of migraine and vascular headaches. It is also used in loss of appetite, poor eating habits and anorexia.

Contraindications

In known hypersensitivity to cyproheptadine, angle-closure glaucoma, stenosing peptic ulcer, symptomatic prostatic hypertrophy, bladder neck and pyloroduodenal obstruction.

Special precautions and warnings

Use with caution in patients with history of bronchial asthma, increased intraocular pressure, hyperthyroidism, cardiovascular disease and hypertension. Prolonged therapy may cause blood dyscrasias. Not be used in newborn or premature infants, elderly and debilitated patients due to dizzness, sedation and hypotension.

Pregnancy and lactation: use only if potential benefit justifies potential risk to fetus

Dosage and direction for use

Dosages should be individualized according to the needs and the response of the patient.

Allergy and pruritus
Adults: 12-16 mg per day in divided doses, not exceeding 32mg/day. Initiate with 4mg (two spoosnful) 3 times a day and adjust according to size and response of patient.
Children (2-6 years): 2mg twice or thrice daily, not exceeding 12mg/day
Children ( 7-14 years): usually 4mg twice or thrice daily, not exceeding 16 mg/day

Migraine and vascular headaches: Recommended dosage is 4mg initially, repeated after half hour if necessary, but not to exceed 8mg in 4-6 hour period.

Appetite stimulant: 12mg/day in 3 divided doses for adults and children of 7-17 years and maximum 8mg/day for children of 2-6 years

Adverse effects

Drowsiness, nausea, dryness of mouth, sedation, dizzness, disturbed coordination, confusion, restlessness, excitation, nervousness, tremor, insomnia, paresthesias, neuritis, convulsions, euphoria, hallucinations, hysteria, hypotension, palpitation, tachycardia, anaphylactic shock, anemia, leukopenia, agranulocytosis, thrombocytopenia, fatigue, diarrhea, epigastric stress, rash, urticarial, photosensitivity, dry nose and throat, wheezing, chills and headache.

Drug interactions

MAO inhibitors prolongs and intensifies anticholinergic effects of cyproheptadine. Cyproheptadine may have additive effects with alcohol and other CNS depressants, e.g., hypnotics, sedatives, tranquilizers and anti-anxiety agents.