What information should be given to a patient experiencing nausea and vomiting regarding possible causes, self‑care measures, and treatment options?

Patient Information for Nausea and Vomiting

What Causes Nausea and Vomiting?

Nausea and vomiting have many possible causes, and identifying the specific trigger is essential for effective treatment. 1, 2

Common Causes Include:

• Infections and food poisoning – viral gastroenteritis is the most frequent cause of acute symptoms lasting less than 7 days 3, 4
• Medications – opioids, antibiotics, antifungals, chemotherapy, and many other drugs can trigger these symptoms 1
• Digestive problems – gastroparesis (delayed stomach emptying), gastritis, acid reflux, or bowel obstruction 1, 5
• Metabolic issues – high calcium levels, electrolyte imbalances, kidney or liver problems, diabetes complications 1, 6
• Neurological conditions – migraines, brain metastases, or inner ear disorders 1, 2
• Pregnancy – especially in the first trimester 7
• Constipation or fecal impaction – can cause significant nausea 1, 2
• Cannabis use – chronic heavy use can paradoxically cause severe cyclic vomiting (Cannabis Hyperemesis Syndrome) 2, 6

When to Seek Immediate Medical Attention

You should go to the emergency department or call your doctor immediately if you experience: 3, 8

• Severe dehydration (decreased urination, extreme thirst, dizziness when standing)
• Inability to keep down any fluids for more than 24 hours
• Severe abdominal pain
• Blood in vomit (red or coffee-ground appearance)
• Severe headache with stiff neck or confusion
• Signs of electrolyte imbalance (muscle weakness, irregular heartbeat, confusion)

Self-Care Measures You Can Try at Home

Dietary Modifications:

• Eat small, frequent meals rather than three large meals per day 3, 8
• Avoid trigger foods including fatty, spicy, or very sweet foods 3
• Try bland foods such as crackers, toast, rice, or bananas when you can tolerate eating 3
• Stay hydrated with small sips of clear fluids (water, broth, electrolyte solutions) throughout the day 3, 8

Other Helpful Measures:

• Rest in a quiet, dark room if symptoms are severe 9
• Avoid strong odors that may worsen nausea 3
• Try ginger (ginger tea or ginger candies) which may help reduce nausea 7

Medical Treatment Options

Your doctor will select medications based on the suspected cause and the specific brain receptors involved in triggering your symptoms. 1, 5

First-Line Medications:

• Dopamine antagonists such as metoclopramide (10 mg three to four times daily), prochlorperazine (5-10 mg four times daily), or haloperidol (0.5-1 mg every 6-8 hours) are typically tried first 1, 5
• Metoclopramide also helps speed stomach emptying, making it particularly useful for gastroparesis 5, 9

If First-Line Treatment Doesn't Work:

• Serotonin (5-HT3) antagonists like ondansetron (4-8 mg two to three times daily) may be added after 4 weeks if symptoms persist 1, 5
• The key principle is adding medications from different drug classes rather than switching from one to another, because different brain receptors are involved 5

Additional Options for Persistent Symptoms:

• Antihistamines such as diphenhydramine or promethazine 1
• Anticholinergic agents like scopolamine patches 1
• Corticosteroids (dexamethasone) particularly effective when combined with other antiemetics 1
• Olanzapine (10 mg once daily) has shown superior effectiveness for breakthrough vomiting in some cases 1, 5
• Benzodiazepines like lorazepam if anxiety is contributing to symptoms 1

Route of Administration:

• Oral medications work well for mild symptoms, but if you're actively vomiting, you may need rectal suppositories, sublingual (under-the-tongue) tablets, or intravenous medications 5
• Ondansetron is available as a dissolving tablet that can be absorbed even when vomiting 5

Important Warnings and Side Effects

Metoclopramide Precautions:

• Has a black box warning for tardive dyskinesia (involuntary muscle movements) with long-term use, though the actual risk may be lower than previously thought 5, 6
• Can cause acute dystonic reactions (muscle spasms) which should be treated immediately with diphenhydramine 50 mg 6
• Should not be used if you have a bowel obstruction 5

Ondansetron Precautions:

• Can prolong the QT interval on your heart rhythm, particularly at high doses 10
• May interact with other medications that affect serotonin levels 10

General Precautions:

• Antiemetics can mask signs of worsening bowel obstruction, so they should not be used if obstruction is suspected 1, 5
• Long-term benzodiazepine use carries risk of dependence 5
• Always inform your doctor of all medications you're taking, including over-the-counter drugs and supplements 2, 6

Special Situations

For Chemotherapy-Related Nausea:

• Preventive treatment is more effective than waiting for symptoms to start – antiemetics should be given 30-60 minutes before chemotherapy 1
• Combination regimens using multiple drug classes (NK-1 antagonists, 5-HT3 antagonists, and corticosteroids) are standard 1

For Pregnancy-Related Nausea:

• Vitamin B6 and ginger are safe first-line options 7
• Most cases improve with supportive care including small frequent meals and adequate hydration 7
• Severe cases (hyperemesis gravidarum) require hospitalization for intravenous fluids and thiamine supplementation 7

For Gastroparesis:

• Proton pump inhibitors combined with metoclopramide address both delayed emptying and acid-related symptoms 6
• If you take opioids, these may be causing or worsening gastroparesis – discuss dose reduction or rotation to a different pain medication with your doctor 2

What to Tell Your Doctor

Provide detailed information about: 2, 8

• Timing and pattern – is it constant or does it come in episodes with symptom-free periods in between?
• Frequency and duration – how many episodes per day/week/month, and how long does each last?
• All medications you're taking, including recent changes
• Relationship to meals – does it occur before, during, or after eating?
• What makes it better or worse – including any triggers you've identified
• Associated symptoms – pain, constipation, headaches, dizziness
• Cannabis use – be honest about frequency and amount, as this is a treatable cause 2, 6

Expected Timeline for Improvement

• Acute symptoms from infections typically resolve within 7 days with supportive care 3
• Medication-induced symptoms should improve within days of stopping the offending drug 2
• Chronic symptoms may take 4 weeks or longer to respond to treatment, and finding the right medication combination often requires trial and adjustment 5, 8
• Use antiemetic medications for the shortest time necessary to control symptoms 3