meclizine hydrochloride

(mek' li zeen)

Bonamine (CAN)

Oral prescription tablets:

Antivert, Antrizine, Dramamine Less Drowsy Formula, Meni-D

 

Pregnancy Category B

 

Drug classes

Antiemetic

Anti-motion sickness drug

Antihistamine

Anticholinergic

 

Therapeutic actions

Reduces sensitivity of the labyrinthine apparatus; probably acts at least partly by blocking cholinergic synapses in the vomiting center, which receives input from the chemoreceptor trigger zone and from peripheral nerve pathways; peripheral anticholinergic effects may contribute to efficacy.

 

Indications

·        Prevention and treatment of nausea, vomiting, motion sickness

·        Possibly effective for the management of vertigo associated with diseases affecting the vestibular system

 

Contraindications and cautions

·        Contraindicated with allergy to meclizine or cyclizine.

·        Use cautiously with lactation, narrow-angle glaucoma, stenosing peptic ulcer, symptomatic prostatic hypertrophy, bronchial asthma, bladder neck obstruction, pyloroduodenal obstruction, cardiac arrhythmias, postoperative state (hypotensive effects may be confusing and dangerous), pregnancy.

 

Available forms

Tablets—12.5, 25, 50 mg; chewable tablets—25 mg; capsules—25, 30 mg

 

Dosages

ADULTS

·        Motion sickness: 25–50 mg PO 1 hr prior to travel. May repeat dose every 24 hr for the duration of the journey.

·        Vertigo: 25–100 mg PO daily in divided doses.

PEDIATRIC PATIENTS

Not recommended for use in children < 12 yr.

GERIATRIC PATIENTS

More likely to cause dizziness, sedation, syncope, toxic confusional states, and hypotension in elderly patients; use with caution.

 

Pharmacokinetics

Route

Onset

Peak

Duration

Oral

1 hr

1–2 hr

12–24 hr

 

Metabolism: T1/2: 6 hr

Distribution: Crosses placenta; may enter breast milk

Excretion: Feces

 

Adverse effects

·        CNS: Drowsiness, confusion, euphoria, nervousness, restlessness, insomnia and excitement, seizures, vertigo, tinnitus, blurred vision, diplopia, auditory and visual hallucinations

·        CV: Hypotension, palpitations, tachycardia

·        Dermatologic: Urticaria, rash

·        GI: Dry mouth, anorexia, nausea, vomiting, diarrhea or constipation

·        GU: Urinary frequency, difficult urination, urinary retention

·        Respiratory: Respiratory depression, death (due to overdose, especially in young children), dry nose and throat

 

Interactions

·        Increased sedation with alcohol or other CNS depressants

 

Nursing considerations

Assessment

·        History: Allergy to meclizine or cyclizine, pregnancy, narrow-angle glaucoma, stenosing peptic ulcer, symptomatic prostatic hypertrophy, bronchial asthma, bladder neck obstruction, pyloroduodenal obstruction, cardiac arrhythmias, postoperative patients, lactation, pregnancy

·        Physical: Skin color, lesions, texture; orientation, reflexes, affect; ophthalmic examination; P, BP; R, adventitious sounds; bowel sounds, normal output, status of mucous membranes; prostate palpation, urinary output

 

Interventions

·        Monitor I & O, and take appropriate measures with urinary retention.

 

Teaching points

·        Take as prescribed. Avoid excessive dosage. Chew the chewable tablets carefully before swallowing.

·        Anti-motion sickness drugs work best if used ahead of time for prevention.

·        Avoid alcohol; serious sedation could occur.

·        You may experience these side effects: Dizziness, sedation, drowsiness (use caution driving or performing tasks that require alertness); epigastric distress, diarrhea, or constipation (take with food); dry mouth (practice frequent mouth care, suck sugarless lozenges); dryness of nasal mucosa (try another motion sickness, antivertigo remedy).

·        Report difficulty breathing, hallucinations, tremors, loss of coordination, visual disturbances, irregular heartbeat.

 

Adverse effects in Italic are most common; those in Bold are life-threatening.