CYCLIZINE HYDROCHLORIDE

CYCLIZINE HYDROCHLORIDE
(sye'kli-zeen)
Marezine, Marzine

CYCLIZINE LACTATE
Marezine Lactate, Marzine
Classifications: antihistamine (h₁-receptor antagonist); antivertigo agent; antiemetic;
Therapeutic:antivertigo; antiemetic; antihistamine
Prototype: Meclizine
Pregnancy Category: B

Availability

50 mg tablets; 50 mg/mL injection

Action

Piperazine antihistamine (H₁-receptor antagonist) that exhibits CNS depression and anticholinergic, antispasmodic, local anesthetic, and antihistaminic activity. Has prominent depressant action on labyrinthine excitability and on conduction in vestibular-cerebellar pathways.

Therapeutic Effect

Produces marked antimotion and antiemetic effects.

Uses

Chiefly for prevention and treatment of motion sickness and postoperative nausea and vomiting.

Contraindications

Increased intraocular pressure; asthma, closed-angle glaucoma; children <6 y.

Cautious Use

Narrow-angle glaucoma; prostatic hypertrophy; elderly; obstructive disease of GU or GI tracts; postoperative patients; pregnancy (category B), lactation.

Route & Dosage

Motion Sickness
Adult: PO 50 mg 30 min before travel, then q4–6h prn (max: 200 mg/d) IM 50 mg q4–6h prn
Child: PO 6–12 y, 25 mg q4–6h prn (max: 75 mg/d) IM 6–12 y, 1 mg/kg t.i.d. prn (max: 75 mg/d)

Postoperative Vomiting
Adult: IM 50 mg 15–30 min before end of operation, may repeat q4–6h (t.i.d.) prn during first few days after surgery

Administration

Oral

Give dose 30 min prior to any activity likely to cause motion sickness.

Intramuscular

Aspirate needle carefully before injecting IM. Anaphylactic reactions following inadvertent IV injection have been reported.
For prophylaxis of postoperative nausea and vomiting, drug usually prescribed with preoperative medication or is administered 20–30 min before expected termination of surgery.
Store tablets in tight, light-resistant container at 15°–30° C (59°–86° F) unless otherwise directed. Store parenteral form in a cold place at 5°–10° C (41°–50° F). When parenteral solution is stored at room temperature for prolonged periods, it may become slightly yellow, but this does not indicate loss of potency.

Adverse Effects (≥1%)

CV: Hypotension, palpitation, tachycardia. GI: Anorexia, nausea, vomiting, diarrhea, or constipation, cholestatic jaundice. CNS: Drowsiness, excitement, euphoria, auditory and visual hallucinations, hyperexcitability alternating with drowsiness, convulsions, respiratory paralysis (rare). Skin: Urticaria, rash. Special Senses: Dry mouth, nose, and throat; blurred vision, diplopia; tinnitus. Other: Pain at IM injection site.

Diagnostic Test Interference

Because cyclizine is an antihistamine, inform patient that skin testing procedures should not be scheduled for about 4 d after drug is discontinued or false-negative reactions may result.

Interactions

Drug: Alcohol, barbiturates, cns depressants (e.g., hypnotics, sedatives, and anxiolytics) may compound effects of cyclizine.

Pharmacokinetics

Onset: Rapid. Duration: 4–6 h. Metabolism: Unknown.

Nursing Implications

Assessment & Drug Effects

Monitor post-operative patient's vital signs closely, as cyclizine can cause hypotension.
Monitor for and report signs of CNS stimulation (e.g., hyperexcitability, euphoria). Dose reduction or discontinuation of drug may be indicated.

Patient & Family Education

Take cyclizine with food or a glass of milk or water to minimize GI irritation.
Do not drive a car or engage in other potentially hazardous activities until reaction to the drug is known. Adverse effects include drowsiness and dizziness.
Alcohol, barbiturates, narcotic analgesic, and other CNS depressants may compound sedative action.

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

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