motion sickness

Pharmacy Practice IV

Prepared by Ibrahim Abdullah, BPharm (Hons) Nottingham, UK.

Motion Sickness // of 5

Motion Sickness (Travel Travail)

Lanta and Banta are discussing the possibility of love. Banta: "I thought I was in love three times." Lanta: "Thought...?" What do you mean?" Banta: "Three years ago, I cared very deeply for a woman who wanted nothing to do with me. Wasn't that love?" Lanta: "No, that was obsession.” Banta: "Then two years ago, I cared very deeply for an attractive woman who didn't understand me. Wasn't that love?" Lanta: "No, that was lust." Banta: "And just last year, I met a woman while I was on a cruise. She was gorgeous, intelligent, a great conversationalist and had a super sense of humor. Everywhere I followed her on that ship, I would get a very strange sensation in the pit of my stomach. Well, wasn't that love?" Lanta: "No. That was motion sickness!"

Synonyms

Kinetosis, seasickness, space sickness (astronauts), travel sickness, camel sickness, etc.

Causes

1. Due to conflicting information fed into the vestibular system (sensing motion, acceleration,

and gravity) and other sensory systems (eyes, skin pressure receptors, and the muscle and

joint sensory receptors), particularly visual system. Information received by the vestibular

system mismatches / dis-coordinates with that received by the eyes.

2. Example: Reading a book while traveling in a car – your eyes detect no movement but

vestibular system and pressure receptors feel the movement.

3. The vestibular system plays more important role than the visual system – blind people do

get motion sickness too.

4. Adaptability. Adaptation occurs with continual exposure to the motion that causes the

motion sickness. So, may experience seasick for one day only and recover for the rest of the

trip.




Symptoms

Brain responds to the mismatch, inducing and resulting in:

a. Epigastric discomfort

b. Nausea

c. Malaise

d. Pallor

e. Sweating

f. Vomiting

Who get it?

1. Very common:

a. 33% of all people

b. 50% of shuttle astronauts

c. 29% of airline pilots

d. 100% of ship passengers become seasick under rough conditions

2. Age: About 58% children affected. Children younger than 2 years of age are rarely affected.

Susceptibility rapidly increases with age, peaking between 4 and 10 years.

3. Gender: Females tend to be more susceptible than males, regardless of age.

Management

1. Education for patients about the causes of motion sickness and how to prevent it can

alleviate anxiety and enhance their enjoyment of travel and recreation.

2. Appropriate management should:

a. Be based on patient characteristics (age, sex, pregnancy, lactation, concomitant

illnesses, allergies, previous motion sickness)

� Elderly passengers tend to be more resistant to motion sickness and may

not require medication. Dosages should be halved and particular care should

be taken with anticholinergics if there is concern about side effects

� Pregnant women are particularly susceptible to nausea caused by motion

sickness. Adequate hydration should be emphasized




� Oral contraceptives enhance susceptibility. Women are also especially

vulnerable during menses

� Anxiety and pre-exposure tendency to facial flushing or nausea correlate

with subsequent motion sickness

b. Depend on type and length of the exposure

� For short-duration exposures

� For longer exposures

� Travelers who wish to sleep

� For extended exposures e.g., a sailing trip

c. Include medicines as prevention

d. Include general preventive recommendations

Prevention - Medicines

The conflicting input within the brain involves neurotransmitters histamine, acetylcholine, and

norepinephrine. Many of the drugs that are used to treat motion sickness act by influencing or

normalizing the levels of these compounds within the vestibular centre in the brain. They

thereby diminish the potential for eye-balance (visual-vestibular) conflict.

If medications are necessary, they are best taken at least half an hour to one hour before

embarking.

1. Antidopaminergics

a. Promethazine hydrochloride (Phenergan). It is useful for both active and prophylactic

treatment of motion sickness

b. Metoclopramide hydrochloride (Maxolon). Particularly if stomach distress is the

predominate symptom. Metoclopramide is effective in pregnancy, but it is a potent

lactation stimulant

2. Anticholinergics

a. Scopolamine hydrobromide or hyoscine (Scopoderm). Cutaneous patch applied

behind the ear to deliver a continuous dose of scopolamine to the systemic

circulation for 3 days. Inhibits vestibular input to the central nervous system,

resulting in inhibition of the vomiting reflex. It may also have a direct action on the

vomiting center




b. Scopolamine is atropine-derivative. Side effects include blurred vision resulting from

dilated pupils, dry mucous membranes

c. Discontinuation may cause withdrawal symptoms - nausea, dizziness, headache, and

equilibrium disturbance

d. In the elderly they can cause psychological problems as side effects

3. Antihistamines

a. Intrinsic anticholinergic properties. Can cause drowsiness, sedation, somnolence,

dizziness, and thickened bronchial secretions. Use with caution in patients with a

history of bronchial asthma, increased intraocular pressure, hyperthyroidism,

cardiovascular disease, or hypertension

b. Diphenhydramine hydrochloride (Benadryl). Safe in pregnant mothers

c. Dimenhydrinate (Dramamine, Gravol). Safe in pregnant mothers

d. Cinnarizine (Stugeron)

e. Meclizine – not sedative, works 24 hours. But not available in Malaysia?

Prevention - Nonpharmacological

1. Herbal preparations: Ginger root (Zingiber officinale) – not proven?

2. Acupressure. Pressure is applied to the P6 acupuncture point on the pericardial meridian –

not proven?

3. Drink and food:

a. Eat a light meal no less than three hours before exposure

b. Avoid heavy, spicy, or fat-rich foods, dairy products and foods high in protein,

calories, or sodium before or on travel




4. Ventilation. Increase ventilation or exposure to cool, fresh air. Open a vent or source of

fresh air if possible.

5. Position:

a. Lie in supine position

b. Do not sit facing backwards from your direction of travel

c. Stay in central location on boat or in airplane – least motion. On a ship, those in

lower level cabins near the center of a ship generally experience less motion than

passengers in higher or outer cabins

d. Sit in the front seat of a car

6. Eye:

a. Avoid visual stimuli (e.g., reading, watching videos)

b. Focus on a stable horizon or fixed stationary external object

7. Others:

a. Limit head movements (e.g., press head into headrest)

b. Isolate yourself from others who may be suffering from motion sickness. Hearing

others talk about motion sickness or seeing others becoming ill can sometimes make

you feel ill yourself

When should refer

1. The distressing symptoms of motion sickness usually stop when the motion that causes it

ceases. But this is not always true. There are people who suffer symptoms for even a few

days after the trip is over.

2. Most cases of motion sickness are mild and self–treatable. However, very severe cases and

those that become progressively worse during or after traveling deserve the attention and

care of a physician with special skill in diseases of the ear, balance (equilibrium), and the

nervous system.

This article is for educational purpose only. The writer welcomes any feedback, which may be sent to

[email protected]

motion sickness

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