Vertigo and motion sickness. Part II: pharmacologic treatment

Ear, Nose & Throat Journal, Jan, 2006 by Timothy P. Zajonc, Peter S. Roland

Table 1. Selected medications approved in the U.S. for motion sickness
and vertigo

Drug               MS   AV   CV   Action

Benzodiazepines
Diazepam                          GABA A-mediated
                                  inhibition in the
                                  vestibular nuclei

Lorazepam                         Same as diazepam

Clonazepam                        Same as diazepam

Antihistamines
Diphenhydramine                   H, blockade;
                                  anticholinergic effects

Dimenhydrinate                    Same as
                                  diphenhydramine

Meclizine                         Same as
                                  diphenhydramine

Cyclizine                         Same as
                                  diphenhydramine

Promethazine                      H, blockade; strong
                                  anticholinergic effects

Anticholinergics
Scopolamine                       M1, M2, and M3 blockade;
                                  M3 blockade is likely
                                  most important

Scopolamine/                      Same as scopolamine
ephedrine *                       alone plus adrenergic
                                  and dopaminergic
                                  effects

Scopolamine/                      Same as scopolamine/
d-amphetamine *                   ephedrine

Neuroleptics
Droperidol/                  ?    Antiadrenergic and
  fentanyl                        antidopaminergic
                                  effects; analgesia
                                  w/fentanyl

Drug               Dosage

Benzodiazepines
Diazepam           Oral: 2, 5, or 10 mg
                   bid to qid;
                   Slow IV: 5 to 10 mg q4h

Lorazepam          Oral: 1 to 2 mg tid;
                   IM/slow IV: 2 mg
Clonazepam         Oral: 0.5 mg tid;

Antihistamines
Diphenhydramine    Oral: 25 to 50 mg
                   q4h to q6h;
                   IM/IV: 10 to 50 mg qid

Dimenhydrinate     Oral: 50 mg q4h to q6h
                   IM/IV: 25 to 50 mg
                   q4h to q6h

Meclizine          Oral: 25 to 50 mg
                   qd to qid

Cyclizine          Oral: 50 mg q4h to q6h

Promethazine       Oral: 25 mg q6h;
                   suppository: 50 mg q1 2h
                   IM: 25 mg q4h to q6h

Anticholinergics
Scopolamine        Oral: 0.6 mg q4h
                   transdermal: 1.5-mg
                   patch delivers
                   1.0 mg qid

Scopolamine/       Oral: 0.6 mg/25 mg q6h
ephedrine *

Scopolamine/       Oral: 0.6 mg/5 to 10 mg
d-amphetamine *    q6h

Neuroleptics
Droperidol/        IM/slow IV: droperidol
  fentanyl         2.5 to 5 mg/fentanyl
                   50 Ng/ml q1 2h

Drug               Precaution

Benzodiazepines
Diazepam           Sedation; avoid in patients
                   w/pulmonary insufficiency,
                   sleep apnea, or liver or
                   kidney disease; addiction
                   is possible

Lorazepam          Same as diazepam

Clonazepam         Same as diazepam

Antihistamines
Diphenhydramine    Sedation

Dimenhydrinate     Sedation

Meclizine          Sedation

Cyclizine          Sedation; may aggravate
                   severe heart failure

Promethazine       Sedation; use w/caution in
                   patients w/renal failure

Anticholinergics
Scopolamine        Sedation, dry mouth,
                   blurred vision, acute angle
                   glaucoma, dermatitis,
                   possible withdrawal
                   symptoms; rare psychosis
                   reported

Scopolamine/       Hypertension, anxiety,
ephedrine *        arrhythmia; use w/caution
                   in patients w/hyperthyroid-
                   ism, diabetes, or glaucoma

Scopolamine/       Same as scopolamine/
d-amphetamine *    ephedrine

Neuroleptics
Droperidol/        Hypotension, respiratory
  fentanyl         depression; use w/caution
                   in patients w/liver or
                   kidney disease

* Both adrenergics are effective as monotherapies.

Key: MS = motion sickness; AV = acute vertigo; CV = chronic vertigo.

Table 2. Selected investigational medications and agents not approved
in the U.S.

Drug                MS      Vertigo   Suspected drug action

Anticholinergics                      [M.sub.1] and
Idaverine            -                [M.sub.2] receptor blockade

Zamifenacin                           [M.sub.3] and
                                      [M.sub.5] receptor blockade

Anticonvulsant                        Stabilization of
Phenytoin                             neuronal membranes in CNS

Calcium
antagonists                           Labyrinth suppression,
Flunarizine                           possibly at the level
cells                                 of the vestibular hair

Cinnarizine                           Same as flunarizine

Nimodipine                            Same as flunarizine;
                                      possible CNS modulation

Nifedipine                            Unknown

Tricyclic                             Strong [H.sub.1] antagonist,
antidepressant                        adrenergic, and anticholinergic
Doxepin                               effects; weak dopaminergic effect

Serotonergics                         5-[H.sub.T1A] agonist effects,
8-OH-DPAT                             probably in the vestibular nuclei

DOI                                   5-[H.sub.T2] agonist effects

Imipramine/                           Increase in concentration of
fluoxetine           (A)              serotonin in synapses

Ondansetron          -                5-[H.sub.T3] receptor blockade,
                                      likely in the area postrema
Others                                3(chemoreceptor trigger zone)

GR203040             (AH)             N[K.sub.1] receptor blockade

LY233053             (A)              NMDA blockade in the vestibular
                                      nuclei and the final common
                                      pathway for vomiting

ORG 2766             (A)              Suppression, possibly in the
                                      vestibular nuclei

Key. MS = motion sickness; CNS = central nervous system; 8-OH-DPAT =
8-hydroxy-2-(di-n propylamino)tetralin; DOI =
1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane; A = in animals; AH =
in animals and humans; NMDA = n-methyl-d-aspartate.