cyproheptadine hydrochloride

Action

Antagonizes effects of histamine at histamine₁-receptor sites, preventing histamine-mediated responses. Also blocks effects of serotonin, causing increased appetite.

Availability

Syrup: 2 mg/5 ml

Tablets: 4 mg

Indications and dosages

➣ Allergy symptoms caused by histamine release (including seasonal and perennial allergic rhinitis); chronic urticaria; angioedema; dermographism; cold urticaria; adjunctive therapy for anaphylactic reactions

Adults: Initially, 4 mg P.O. q 8 hours. Maintenance dosage is 4 to 20 mg/day in three divided doses, to a maximum dosage of 0.5 mg/kg/day.

Children ages 7 to 14: 2 to 4 mg P.O. q 12 hours. Don't exceed 16 mg/day.

Children ages 2 to 6: 2 mg P.O. q 12 hours. Don't exceed 12 mg/day.

Off-label uses

• Vascular cluster headaches

• Anorexia nervosa

• Cushing's syndrome

Contraindications

• Hypersensitivity to drug

• Alcohol intolerance (syrup only)

• Bladder neck obstruction

• Angle-closure glaucoma

• Ulcer disease

• Symptomatic prostatic hypertrophy

• MAO inhibitor use within past 14 days

Precautions

Use cautiously in:

• hepatic impairment

• elderly patients

• pregnant patients (safety not established)

• breastfeeding patients.

Administration

• Give with food or milk to decrease GI upset.

Adverse reactions

CNS: drowsiness, dizziness, excitation (especially in children), fatigue, sedation, hallucinations, disorientation, tremor

CV: palpitations, hypotension, arrhythmias

EENT: blurred vision, nasal dryness and congestion, dry throat

GI: constipation, dry mouth

GU: urinary retention, urinary frequency, ejaculatory inhibition, early menses

Respiratory: thickened bronchial secretions

Skin: rash, photosensitivity

Other: weight gain

Interactions

Drug-drug. CNS depressants (including opioid analgesics, sedative-hypnotics): increased CNS depression

MAO inhibitors: intensified, prolonged anticholinergic effects

Drug-diagnostic tests. Allergy skin tests: false-negative reactions

Drug-behaviors. Alcohol use: increased CNS depression

Patient monitoring

• Monitor patient for excessive anti-cholinergic effects.

• Assess for excessive CNS depression.

• Discontinue drug 4 days before diagnostic skin testing.

Patient teaching

• Advise patient to take drug with food to minimize GI upset.

• Caution patient not to use other CNS depressants, sleep aids, or alcohol during therapy.

• Instruct patient to avoid driving and other hazardous activities until he knows how drug affects concentration and alertness.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, and behaviors mentioned above.