Periactin, Vimicon 
Classifications: antihistamine (h1-receptor antagonist); antipruritic;
Therapeutic: antihistamine
; h1-receptor antagonist
Prototype: Diphenhydramine
Pregnancy Category: B


4 mg tablets


Potent piperidine antihistamine with pharmacologic actions that acts by competing with histamine for H1-receptor sites on effector cells, thus preventing histamine-mediated responses.

Therapeutic Effect

Has significant antipruritic, local anesthetic, and antiserotonin activity. Produces mild central depression and moderate anticholinergic effects.


Symptomatic relief of various allergic conditions, including hay fever, vasomotor rhinitis, allergic conjunctivitis, urticaria caused by cold sensitivity, and pruritus of allergic dermatoses. Effective in treatment of anaphylactoid reactions as adjunct to epinephrine and other standard measures after acute symptoms have been controlled.

Unlabeled Uses

Cushing's disease, carcinoid syndrome, vascular headaches, appetite stimulant.


Hypersensitivity to cyproheptadine or other H1-receptor antagonist antihistamines; acute asthma attack; lactation. Safe use in children <2 y not established.

Cautious Use

Older adult and debilitated patients; patients predisposed to urinary retention; glaucoma; asthma; COPD; hyperthyroidism; cardiovascular or hepatic disease, hypertension; GI or GU tract obstruction, children with a family history of SIDS; pregnancy (category B).

Route & Dosage

Adult: PO 4 mg t.i.d. or q.i.d. (4–20 mg/d), max 0.5 mg/kg/d
Geriatric: PO Start with 4 mg b.i.d.
Child: PO 0.25 mg/kg/d in 3–4 divided doses (max: 12 mg/d for 2–6 y, 16 mg/d for 6–12 y)


  • GI adverse effects may be minimized by administering drug with food or milk.
  • Store in tightly covered container at 15°–30° C (59°–86° F) unless otherwise directed.

Adverse Effects (≥1%)

GI: Dry mouth, nausea, vomiting, epigastric distress, appetite stimulation, weight gain, transient decrease in fasting blood sugar level, increased serum amylase level, cholestatic jaundice. CNS: Drowsiness, dizziness, faintness, headache, tremulousness, fatigue, disturbed coordination. Respiratory: Thickened bronchial secretions. Skin: Skin rash. Special Senses: Dry nose and throat. Urogenital: Urinary frequency, retention, and difficult urination.

Diagnostic Test Interference

As a general rule, antihistamines are discontinued about 4 d before skin testing procedures are to be performed because they may produce false-negative results.


Drug: Alcohol and cns depressants add to CNS depression; tricyclic antidepressants and other anticholinergics have additive anticholinergic effects; may inhibit pressor effects of epinephrine.


Absorption: Readily absorbed from GI tract. Duration: 6–9 h. Distribution: Distribution into breast milk not known. Metabolism: In liver. Elimination: In urine.

Nursing Implications

Assessment & Drug Effects

  • Monitor level of alertness. In some patients, the sedative effect disappears spontaneously after 3–4 d of drug administration.
  • Since drug may cause dizziness, supervision of ambulation and other safety precautions may be warranted.

Patient & Family Education

  • Avoid activities requiring mental alertness and physical coordination, such as driving a car, until reaction to the drug is known.
  • Drug causes sedation, dizziness, and hypotension in older adults. Report these symptoms. Children are more apt to manifest CNS stimulation (e.g., confusion, agitation, tremors, hallucinations). Reduction in dosage may be indicated.
  • Cyproheptadine may increase and prolong the effects of alcohol, barbiturates, narcotic analgesics, anxiolytics, and other CNS depressants.
  • Monitor weight and keep physician informed of any significant weight gain.
  • Maintain sufficient fluid intake to help to relieve dry mouth and also reduce risk of cholestatic jaundice.

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug

© 2006-2022 Last Updated On: 11/22/2022 (0)
Wait 20 seconds...!!!