Medical Treatment 

Therapy is outlined for symptomatic treatment of dizziness presumed to be of peripheral origin (Table 7):

*Usual adult starting dose, can be increased by factor of 2 to 3. The most common side effect is drowsiness.

**The combination preparations Donphen and Donnatal each contain a mixture of atropine alkaloids with approximately 1/4 grain (15-16.2 mg) phenobarbital.

***Note the very low dose when compared to usual antipsychotic levels. Still, the patient should be observed for dystonias.

When a definitive diagnosis such as vestibular schwannoma, autoimmune disorder, perilymph fistula, or systemic vasculitis has been made, the therapy must be directed to the underlying disorder.

Although most of the drugs used for dizziness are loosely referred to as vestibular suppressants, their mechanism of action may not be defined and it is often unclear which agents will be effective in a given patient. The primary vestibular afferent system could be suppressed directly or indirectly through the inhibitory portion of the vestibular efferent system. An important effect of some agents may be to act on other sensory systems such as proprioceptive or visual inputs to the vestibular nuclei of the brainstem.

Few controlled studies have investigated the response of patients with presumed peripheral vestibular dysfunction. Most of the drugs used are empirical based on studies of the prevention of motion sickness in normal subjects or of the various regimens employed by otologists for Meniere's syndrome. Each of the drug classes are discussed separately.  

Antihistamines are among the most commonly employed agents in the treatment of dizziness. The initial drug usually employed is meclizine hydrochloride in doses up to 50mg three times per day. Since the main side effect of antihistamines is drowsiness, the smallest dose should be used initially, even as low as 12.5 mg two to three times per day.

For dizziness, antihistamines falling into the H1 antagonist group are used. Possibly the H1 blockers, effective in motion sickness, act by central antagonism of acetylcholine, as does scopolamine. An excellent drug as a second choice is Promethazine, (Phenergan® ), a phenothiazine with the strongest ACh-blocking action. The usual starting dose is 25 mg three times per day, but if this amount produces drowsiness and still has a positive effect the drug dosage may be reduced to 12.5 mg three times a day.

Anticholinergics that block the muscarinic effect of Ach have been widely used and studied for the prevention of motion sickness. Atropine acts centrally to stimulate the medulla and cerebrum, but the closely related alkaloid scopolamine is more widely used.

Transdermal delivery of scopolamine may prevent or mitigate the nausea and vomiting associated with motion sickness, but not the dizziness. In general, transdermal scopolamine is not useful in patients with acquired vestibulopathy. Frequent side effects are blurred vision and dry mouth, in addition to occasional confusion. Some patients have significant difficulty when they try to discontinue scopolamine patches. A side effect of low dose scopolamine or atropine is the transient bradycardia (4 to 8 beats less per minute) associated with the peak action of oral scopolamine at 90 minutes and diminishing thereafter.

Sympathomimetics have been used in the treatment of motion sickness, particularly in combination with anticholinergics. The sole agent in this class that may have an application in combination with other drugs is ephedrine. Tolerance may develop after a few weeks of treatment.

Antiemetics may be used when prominent nausea is an accompanying feature of the patient's complaint. Many of the antihistaminic and anticholinergic drugs listed here are also used for their antiemetic actions. Prochlorperazine (Compazine® ) should be used with caution, particularly by the intramuscular route, because of the high incidence of dystonic reactions. Because promethazine (Phenergan® ) has a significant antiemetic effect, this drug is particularly useful when there is prominent nausea.

Tranquilizers is the general name given to include drugs from different classes having central and probably peripheral effects. Drugs include benzodiazepines, butyrophenones, and phenothiazines. Diazepam (Valium® ) is one of the most widely prescribed drugs for the treatment of dizziness. Many believe it should not be the first choice, primarily because of the significant potential for habituation and depression, and because it can be the actual cause of dizziness. Nonetheless, it does remain the first choice of many otoneurologists or otologists. Other longer-acting benzodiazepines may be helpful in certain patients, but no study has substantiated their effectiveness. Haloperidol in small oral doses (0.5 mg three times a day) is effective in many patients with peripheral vestibular dysfunction who are not helped by other antidizziness medications.

Combination preparations and other agents, include those listed in Table 6 are frequently useful, particularly the combination of ephedrine and promethazine. Some other agents and regimens used primarily in the medical management of Meniere's disease are listed. Low sodium diets and diuretics have been helpful with some patients. In the belief that in some cases an effect on blood supply to the peripheral end organ might be a factor, agents such as cyclandelate have been used. The general approach to the patient with an acute or chronic vestibulopathy would be first to employ an antihistamine such as Meclizine hydrochloride. If this is not helpful, the next step would be to use promethazine (Phenergan® ), and if this is ineffective, low doses of haloperidol or low dose diazepam always keeping in mind the potential for habituation with benzodiazepines.