I often am asked about over-the-counter medications and which ones are best.  Meclizine HCl is one of those medications.  The following is a summary of both good and bad points about Meclizine.

Meclizine Uses

Primarily for the treatment of nausea, vomiting or dizziness associated with motion sickness.  There is some evidence supporting the use of meclizine to manage vertigo.

Meclizine Dosages

• Motion Sickness (Adults): 25 to 50mg to be taken 1 hour before travel.  You can repeat the dose every 24 hours as needed.  Do not exceed 2 tablets in 24 hours.  Children under 12 years old: Consult physician.
• Vertigo:  25 to 100mg daily in divided doses depending on response and severity of symptoms.

Action in Body

Meclizine is an antihistamine.  It is better at blocking the vasopressor response to histamine.  A vasopressor response is where the blood vessels constrict.  So Meclizine HCl is somewhat more effective at blocking this constriction.

It is not as effective at blocking the actions of acetylcholine.  Acetylcholine has a lot of effects in the body.  Especially in your central nervous system and skeletal and cardiac muscles.  This blocking of acetylcholine partially explains some of the side effects (below) you'll see with Meclizine HCl.

Once taken, you will see the effects of meclizine within 30 to 60 minutes depending on the dose.  The duration of action can range from 6 hours at low dose to 12 to 24 hours at higher doses.

When Not to Take

You should not take Meclizine HCl if you have ever had an allergic reaction to Meclizine or any of it's components.

Warnings Against Use

If you have any allergy to aspirin you would be better off avoiding Meclizine because it may contain FD&C Yellow Number 5 (tartrazine).  This substance can cause an allergic type reaction in susceptible patients.  This is more frequently seen in patients allergic to aspirin.

It should also be used with caution in the following cases because of it's anticholinergic effects:

• Asthma
• Emphysema
• Chronic Bronchitis
• Glaucoma
• Enlargement of the Prostate

Because Meclizine HCl can cause drowsiness be cautious if you perform any activities that require alertness: driving, operating heavy machinery, etc.

Because no reliable studies have been performed in children under 12 years of age it's use in this age group is discouraged.

Pregnancy/Lactation

Meclizine HCl should be used during pregnancy and lactation ONLY if the benefit outweighs the risks.  From the limited amount of information available, it appears as Meclizine HCl does not exert any adverse effects on the fetus during pregnancy.  But, as always, this is an area where you and your doctor should exercise caution.

Interactions

Alcohol and sedatives can compound the drowsiness from Meclizine HCl.

Side Effects

Most common side effects include drowsiness (in some cases excitation), blurred vision, dry mouth, low blood pressure, dry nose and throat.