This is an update of an article that appeared in the May/June 2000 issue of Advance for Audiologists (www.advanceforaud.com )
Treating Dizziness with Antivert
Research indicates that long-term use may not be the best solution
By Alan L. Desmond, Au.D., CCC-A and R.Brian Collie, D.O., RPh
Considering how frequently Antivert is prescribed for dizziness, its effectiveness has been measured in remarkably few studies. While there is general agreement among specialists that vestibular compensation is inhibited by the use of vestibular or central nervous system sedative medications, the literature suggests that these types of medications are used the majority of the time when a patient presents in the primary care setting with the complaint of dizziness, vertigo or imbalance. Well over half of these patients – 61 percent to 89 percent – receive some type of medication following their initial visit, Antivert being the most common. In one study, approximately 90 percent of patients subsequently diagnosed with benign paroxysmal positional vertigo (BPPV) were given Antivert prior to receiving a correct diagnosis. However, another study found that in the general population only 31 percent of patients receiving medication for dizziness found it helpful.
More recent studies indicate little change in prescribing patterns since this article came out in 2000. Newman-Toker et al. (2009) report that approximately 60% of patients diagnosed with vestibular disorders in the Emergency Department (ED) are prescribed meclizine, and that 58% of patients diagnosed with BPPV in the ED are prescribed meclizine. A very recent (2013) Harvard Medical School report states that 21%-22% of elderly patients with balance disorders (as opposed to vertigo) are given meclzine.
Dizziness is a vague term that can mean different things to different people. A recent study reports that of elderly patients complaining of dizziness, only 25 percent were describing rotary vertigo. On further questioning, approximately 75 percent described their dizziness as unsteadiness, dysequilibrium, loss of balance, or pre-syncopal lightheadedness. Although etiology of these complaints was not obtained, we know that BPPV is the most common cause of vertigo, and dysequilibrium and unsteadiness can be the result of vestibular and/or non-vestibular pathology. Antivert (meclizine hydrochloride) is an antihistamine. According to the Physicians Desk Reference, it is effective for:
“management of nausea and vomiting and dizziness associated with motion sickness” and possibly effective for “management of vertigo associated with diseases affecting the vestibular system.”
Antivert is not recommended for complaints of unsteadiness, dysequilibrium, loss of balance, or pre-syncopal lightheadedness.
Medication taken to suppress vestibular symptoms ideally should be used only during the acute stage following vestibular insult. During the acute phase of vestibular dysfunction, typically lasting three to five days, vestibular suppressants are helpful in reducing the activity in the vestibular nuclei and cerebellum. Asymmetry in activity in these areas creates the acute symptoms of vestibular-induced vertigo. In order for natural or therapeutically enhanced compensation to take place, the brain eventually must be made aware that an asymmetry exists. Appropriate treatment following the acute phase encourages activity to promote central compensation rather than suppression of stimulation needed for compensation.
The intensity of vertigo associated with BPPV may be lessened when using Antivert. However, this is a less than ideal treatment for two reasons: a therapeutic dosage of Antivert creates a lasting sedating effect only to marginally reduce the intensity of symptoms, which last only a few seconds, and canalith repositioning procedures are extremely effective in relieving the symptoms of positional vertigo. The AAO-HNS Clinical Practice Guideline for BPPV released in 2008 recommends against the use of vestibular supressants for BPPV.
Many patients describing dizziness do not experience vertigo and may have perfectly normal vestibular function. However, since suppressant medications may hinder the function of the vestibular apparatus at a time when the patient is most dependent upon it, these patients actually may experience greater symptoms.
In 1972 a randomized, double-blind crossover study indicated that meclizine had a greater effect than a placebo on diminishing symptoms and signs of vertigo of vestibular origin. Scopolamine has been shown to be more effective than meclizine in treating the symptoms of motion sickness. We are aware of no studies that indicate meclizine provides any benefit for complaints of dysequilibrium, imbalance or lightheadedness.
Is there a role in rehabilitation?
Lauter, Lynch, Wood, and Schoeffler (1999) performed a battery of tests on normal subjects using meclizine and also noted increased subjective drowsiness and decrease in eye–hand reaction test scores. Interestingly, they found that these subjects had improved eye–hand reaction tasks at 2 days after medication compared with placebo. The implications of this are unknown, but the authors suggest that there may be a “cortical activating” effect related to CNS plasticity. In other words, they suspect that the CNS reaction to a CNS sedative would be to overcompensate and create an improvement in reaction time. Contrary to current popular thinking among vestibular specialists, they infer that early short-term use of meclizine may actually enhance vestibular rehabilitation and central compensation
Next week, we will discuss potential negative effects of taking meclizine.