ANTIVERT
Clinical safety rating: caution
Comprehensive clinical and safety monograph for ANTIVERT (ANTIVERT).
Antivert (meclizine) is a piperazine H1 histamine receptor antagonist with central anticholinergic and sedative properties. It suppresses the chemoreceptor trigger zone and labyrinthine apparatus, reducing vestibular stimulation and vertigo.
| Metabolism | Hepatic metabolism via hydroxylation and conjugation; not extensively metabolized by CYP450; main metabolite is norchlorcyclizine. |
| Excretion | Primarily renal (urine) as unchanged drug and metabolites; biliary excretion is minimal. Approximately 80% excreted unchanged in urine. |
| Half-life | Terminal elimination half-life is 35–50 hours in adults; prolonged in renal impairment. |
| Protein binding | 75–90% bound to plasma proteins, primarily albumin. |
| Volume of Distribution | 5–10 L/kg; large due to tissue distribution and high lipophilicity. |
| Bioavailability | Oral: 25–30% due to extensive first-pass metabolism; IM: 70–90%. |
| Onset of Action | Oral: 15–60 minutes; IM: 10–30 minutes; IV: immediate. |
| Duration of Action | Oral/IM: 12–24 hours; IV: 6–12 hours; clinical effects taper slowly. |
25-100 mg orally daily in divided doses 2-4 times daily; maximum 400 mg/day.
| Dosage form | TABLET |
| Renal impairment | CrCl 10-50 mL/min: administer 50% of dose; CrCl <10 mL/min: administer 25% of dose. |
| Liver impairment | No specific guidelines; use with caution in severe hepatic impairment (Child-Pugh Class C) due to potential accumulation. |
| Pediatric use | Not recommended for children under 12 years; for ages 12 and older, dose as per adult dosing. |
| Geriatric use | Start at lowest effective dose; monitor for anticholinergic effects (sedation, confusion, urinary retention). |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for ANTIVERT (ANTIVERT).
| Breastfeeding | Meclizine is excreted into breast milk in small amounts. M/P ratio not established. Probably compatible with breastfeeding; however, monitor infant for drowsiness or irritability. Avoid use in nursing mothers of premature or jaundiced infants. |
| Teratogenic Risk | Antivert (meclizine) is classified as FDA Pregnancy Category B. Animal studies have not demonstrated fetal risk, but no adequate human studies exist. First trimester: theoretical risk based on antihistamine class, but no specific teratogenic effects identified. Second and third trimesters: generally considered safe; however, use only if clearly needed. |
■ FDA Black Box Warning
None
| Common Effects | Application site reactions burning irritation itching and redness |
| Serious Effects |
["Hypersensitivity to meclizine or any component of the formulation.","Acute narrow-angle glaucoma (due to anticholinergic effects)."]
| Precautions | ["Drowsiness and sedation may impair ability to drive or operate machinery.","Anticholinergic effects (dry mouth, blurred vision, urinary retention) – use caution in patients with narrow-angle glaucoma, prostatic hyperplasia, or pyloroduodenal obstruction.","May mask ototoxicity symptoms during concomitant aminoglycoside therapy.","Elderly patients more sensitive to anticholinergic and sedative effects."] |
| Food/Dietary | No significant food interactions. However, alcohol should be avoided due to additive CNS depression. |
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| Fetal Monitoring | No specific monitoring required. Routine prenatal care. Monitor for maternal hypotension with IV use if applicable. Assess fetal heart rate if severe maternal hypotension occurs. |
| Fertility Effects | No known effects on fertility. Antihistamines may cause anticholinergic effects; theoretical potential for altered cervical mucus or tubal motility, but not clinically significant. |
| Clinical Pearls | Antivert (meclizine) is an antihistamine with anticholinergic properties used primarily for vertigo and motion sickness. Its onset is within 1 hour, duration 12-24 hours. Avoid in narrow-angle glaucoma, prostatic hypertrophy, and urinary retention. Can cause drowsiness; caution when driving or operating machinery. Use with caution in elderly due to fall risk. Not effective for motion sickness prophylaxis if taken after symptoms develop. |
| Patient Advice | Take Antivert at least 1 hour before travel for motion sickness. · Do not drive or operate heavy machinery until you know how this medication affects you. · Avoid alcohol and other CNS depressants as they may increase drowsiness. · Contact your doctor if you experience blurred vision, dry mouth, or difficulty urinating. · This medication may cause drowsiness; take it at bedtime if possible. |