Nausea and Vomiting: Not Always in Sync

Pharmacy TimesJuly 2016 Digestive Health
Volume 82
Issue 7

Nausea and vomiting are symptoms of many different conditions, such as infection, food poisoning, motion sickness, concussion, appendicitis, and various other disease states.

Nausea is defined as the unpleasant, painless urge to vomit. Generally an intended protective mechanism, vomiting is an organized, autonomic response resulting in the forceful ejection of stomach contents through the mouth. Nausea and vomiting are symptoms of many different conditions, such as infection, food poisoning, motion sickness, concussion, appendicitis, and various other disease states. Although nausea and vomiting are frequently discussed together, nausea can occur without vomiting or may precede or follow it.1-3


Individuals often experience nausea accompanied by autonomic symptoms, such as pallor, altered heart rate, diaphoresis, and salivation.4 Vomiting involves a series of events leading to the expulsion of the gastric and, often, the small intestinal contents. The pathophysiologies of nausea and vomiting are poorly understood, as there are many contributing factors to each.5,6

The brain’s vomiting center, located in the medulla, can induce vomiting when it is stimulated. This center can be activated directly or indirectly following input from the gastrointestinal tract, the cerebral cortex and thalamus, the vestibular region, or the chemoreceptor trigger zone. Because the vomiting center is not protected by the bloodbrain barrier, it is easily permeated by irritants.5,6

The several neurotransmitters involved in the nausea and vomiting process are not limited to dopamine, histamine, substance P, and serotonin. Although medications are used to target these pathways in the prevention and treatment of nausea or vomiting, many medications may induce nausea or vomiting, as well (Table 17).


Nausea is a subjective feeling that is sometimes given minimal attention by health care providers who may view it as an annoying side effect and not as a notable issue that requires treatment.8 Vomiting can lead to serious consequences, such as aspiration pneumonia. In addition, severe and repetitive vomiting can result in disturbances in the acid-base balance, dehydration, malnutrition, and electrolyte depletion. Continual vomiting may result in the erosion of tooth enamel, thereby increasing tooth sensitivity.4,8

Although many cases of nausea and vomiting may be self-eliminating, some may warrant the use of medications. For serious cases, prescription medications are often recommended; however, OTC treatment options are often used, as well, with patients consulting pharmacists for recommendations regarding nausea and vomiting. In addition to serving as a medication reference, pharmacists should also be knowledgeable about common conditions that may require referral for further investigation (Online Table 26,7).

Table 2. Conditions and Patient Presentations Requiring Referral


Signs that Require Referral

Appendicitis or bowel obstruction

Severe abdominal pain in the middle or right lower quadrant

Bleeding ulcer or other serious condition, such as cancer

Blood-stained vomit and/or black, tarry stools

Children younger than 1 year who are not urinating, or are listless, lethargic, or crying

This presentation requires referral


Dark urine and/or yellow discoloration of the skin or eyes, along with cold and flu symptoms


Headache or stiff neck; normal light hurts the eyes

Pregnancy or lactation

If an in-home pregnancy test produces a positive result, refer the patient to a physician for confirmation

Serious head injury (eg, concussion)

History of recent head injury, headache, blurred vision, numbness, or tingling

Acute myocardial infarction, bulimia nervosa, congestive heart failure, gastroparesis, pyelonephritis, migraine headache, pancreatitis, jaundice, urinary tract infection, seizure, and stroke

If suspected, these conditions require referral

OTC Medications

The OTC agents used to treat or prevent nausea and vomiting include various antihistamine products. These agents are typically effective, especially when the nausea or vomiting is due to vestibular causes such as motion sickness.2,5 Patients receiving these medications should be notified of their potential anticholinergic adverse effects, such as drowsiness, blurred vision, dry mouth, and urinary retention. Because of these effects, these medications should be used with caution in patients with asthma, glaucoma, or enlargement of the prostate gland. In addition, these medications may impair the mental and/or physical abilities required for performing tasks such as driving or operating machinery. The concomitant use of alcohol or other central nervous system depressants may have an additive effect. Age restrictions apply to these medications and should be reviewed prior to administration (Online Table 39,10).

Table 3. OTC Antihistamine Antiemetics

Medication (Brand)

Age Restrictions


Dimenhydrinate (Dramamine)

Do not use in children younger than 2 years

Motion sickness



Do not use in children younger than 2 years

Motion sickness (off-label)



Do not use in children younger than 12 years

Motion sickness

Emetrol—an OTC medication that contains a mixture of fructose, glucose, and phosphoric acid—exerts its antiemetic action by delating gastric emptying time and decreasing smooth muscle contraction. Patients with diabetes should use Emetrol with caution, as more than 5 doses should not be taken within 1 hour.9 Bismuth subsalicylate has also been shown to have antiemetic properties. It may cause darkening of the stool or tongue and should not be taken by individuals with an aspirin allergy. Ginger and peppermint are natural remedies that may be used to help decrease stomach contractions, which may cause nausea.11

Pharmacists can play a role in recognizing symptoms of dehydration and suggest that patients consume small amounts of clear liquids or beverages containing electrolytes. Oral rehydration solutions may also be used in mild to moderate cases.7,12,13


As frontline health care providers, pharmacists must obtain thorough medical and medication histories to identify underlying causes of nausea and/or vomiting, and treat or refer patients. Pharmacists should be alert to signs of underlying conditions, and pregnancy should always be considered in women of childbearing age. If a condition is deemed self-treatable, pharmacists can be excellent resources for choosing optimal OTC products for symptom management. As medication experts, pharmacists are prepared to recommend optimal therapy based on patient presentation.6,9,12,13

Dr. Moore is an assistant professor at Howard University College of Pharmacy.


  • Nausea and vomiting. Cleveland Clinic website. Accessed May 10, 2016.
  • Scorza K, Williams A, Phillips JD, Shaw J. Evaluation of nausea and vomiting. Am Fam Physician. 2007;76(1):76-84.
  • Porter RF, Gyawali CP, Prakash C. Nausea and vomiting. American College of Gastroenterology website. Accessed May 10, 2016.
  • Wilhelm SM, Dehoorne-Smith ML, Kale-Pradhan PB. Prevention of postoperative nausea and vomiting. Ann Pharmacother. 2007;41(1):68-78.
  • Becker D. Nausea, vomiting, and hiccups: a review of mechanisms and treatment. Anesth Prog. 2010;57(4):150-157. doi: 10.2344/0003-3006-57.4.150.
  • Truter I. Evidence based pharmacy practice: Nausea. S Afr Pharm J. 2008;75(7):12-18.
  • Bouwer A. Nausea and vomiting: an approach for the pharmacist. S Afr Pharm J. 2011;78(7):28-32.
  • Smith HS, Smith JM, Smith AR. An overview of nausea/vomiting in palliative medicine. Ann Palliat Med. 2012;1(2):103-114. doi: 10.3978/j.issn.2224-5820.2012.07.06.
  • Vande Griend JP. The pharmacist’s role in treating nausea and vomiting. Emetrol website. Published September 2009. Accessed May 11, 2016.
  • Prunty JJ, Prunty LM. An outpatient approach to nausea and vomiting. US Pharmacist. 2013;38(12):24-28.
  • Vann MR. 4 natural remedies for nausea. Everyday Health website. Updated June 11, 2015. Accessed May 11, 2016.
  • Terrie YC. Antiemetics: putting a stop to motion sickness. Pharmacy Times website. Published November 12, 2012. Accessed May 11, 2016.
  • Terrie YC. Self-treatment with OTC antiemetics. Pharmacy Times website. Published July 13, 2010. Accessed May 11, 2016.

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