Anti-Emetics

Question 1

What are some triggers for nausea?

Answer 1

Smells, sights, memories

Stimulus from inner ear (motion sickness)

Chemical in blood (can be allergens, drug-related, pregnancy, or toxins)

GI tract (stomach flu)

Question 2

How common is nausea and vomiting in drug-related side effects?

Answer 2

Only 2%, not a big plater

Diarrhea is more common especially in kids (20% in kids)

Question 3

What are some common agents that can cause drug-induced nausea and vomiting?

Answer 3

Antibiotics (may have to ride it out)

NSAIDs (take with food)

CCBs (Change or d/c agent)

Opiates (reduce dose)

Plan B (pre-use Gravol)

Question 4

What are some uses of Gravol?

Answer 4

Motion sickness

Post-operative vomiting

Radiation therapy

Ménière’s disease

Drug-induced causes (uncommon)

Question 5

What are some non-pharmacological treatments for motion sickness?

Answer 5

1. Focus on a distant area on horizon
2. Fresh air can help/breath deeply
3. Sit in the middle of the ship or plane

Question 6

What are some pharmacological options for motion sickness?

Answer 6

1. Dimenhydrinate (salt of diphenhydramine)
2. Scopolamine
3. Meclizine
4. Diclectin (Doxylamine/Pyridoxine)

Question 7

What is the mechanism of action for dimenhydrinate?

Answer 7

Stimulus from the inner ear due to motion has cholinergic and histamine response.

Diphenhydrinate has both anti-cholinergic and antihistamines, so it takes care of motion sickness effectively

Question 8

What are some side effects associated with dimenhyrdrinate?

Answer 8

It is a 1st gen antihistamine derivative, so it shares those side effects

Drowsiness

Drying up effect due to anti-cholinergic effect

Question 9

When should dimenhydrinate be taken?

Answer 9

This is not a rescue drug, take it a few hours before an expected activity that could cause motion sickness

Question 10

What is the safety of dimenhydrinate?

Answer 10

Very safe and can be used in paediatrics (kids under 2 need MD counselling)

Question 11

What is the efficacy of Scopolamine?

Answer 11

It has anti-cholinergic activity, but no antihistamine

Ex. Transdermal V (no longer available)

Sedation/dry mouth is a greater concern in Scopolamine vs. dimenhydrinate

Question 12

What is the efficacy of meclizine?

Answer 12

It has both antihistamine and anti cholinergic (but less side effects)

Meclizine works great but dimenhydrinate (Gravol) is just so popular

OD dosing 1h before travel (more convenient than dimenhyrdinate)

Unfortunately discontinued in Canada

Question 13

Are second-gen antihistamines effective in treating motion sickness?

Answer 13

Second-gen antihistamines do not have anti-cholinergic effects, a significant component of motion sickness. Therefore second-gen antihistamines are ineffective in motion sickness

Question 14

What is the significance of pressure points in motion sickness?

Answer 14

The P6 pressure point (located on the wrist) if impinged, it can help change the perception of motion sickness.

It can be applied immediately

Question 15

What is the efficacy of ginger in motion sickness?

Answer 15

It is the poster boy for herbal anti-emetics

More proof for morning sickness, motion sickness not so much.

Not helpful for motion sickness (go for one of the pharmacological options)

Question 16

What the ingredients in “Gravol Ginger”?

Answer 16

Only ginger

Does not contain dimenhydrinate

Do not use Gravol Ginger, use original Gravol (dimenhydrinate)

Question 17

What is the correlation between human chorionic gonadotropin and pregnancy?

Answer 17

It rises in early pregnancy and peaks at week 10. After Week 15, hCG levels remain stable

This time is associated with morning sickness

Question 18

How many pregnant women need medicine for nausea and vomiting?

Answer 18

About 10% (need to be careful about drug use in pregnant women due to fetal risk)

We also need to consider that vomiting can actually be worse for child than anti-emetics

Question 19

What is a common agent used as an anti-emetic in pregnant women?

Answer 19

Diclectin: (doxylamine (first gen antihistamine) and pyridoxine(Vitamin B6))

Question 20

Can birth defects occur without exposure to toxins, drugs, or injury?

Answer 20

Yes, birth defects can occur without these external factors. It is natural for a small number of babies to be born with birth defects

Question 21

What is the efficacy of Diclectin (doxylamine and pyridoxine)?

Answer 21

Some claim that Diclectin has minimal benefit vs. placebo

While the latest references recommend Diclectin

Question 22

Can Diclectin be taken alongside dimenhydrinate?

Answer 22

Yes it is possible

10mg DIclectin QID + 50-100mg Dimenhyrdinate Q4-6H

Diclectin is an add-on therapy, so don’t stop using existing agents