Nausea and Vomiting

Perform laboratory work and other diagnostic studies as suggested by the history, physical examination, and differential diagnosis. Tests may include the following:

	Complete blood count (CBC) with differential
	Blood urea nitrogen (BUN), creatinine, electrolytes
	Glucose
	Amylase and lipase if symptoms of pancreatitis are present
	Liver function tests (LFTs) and hepatitis serologies for possible acute hepatitis
	Blood cultures and other fever workup as needed (see chapter Fever)
	Computed tomography (CT) scan of the brain if neurologic symptoms are present (see chapter Neurologic Symptoms)
	Cortisol and cortrosyn stimulation test if indicated (eg, fatigue, weakness, unexplained abdominal pain, weight loss, orthostasis; usually in late-stage AIDS)
	If odynophagia or dysphagia is present (see chapter Esophageal Problems )
	Electrocardiogram if patient has chest pain or suspicious symptoms
	Lactic acid levels if lactic acidosis is suspected
	Pregnancy test if indicated
	Consult with an HIV expert to determine whether hospitalization or other laboratory tests are needed

Once the diagnosis is made, appropriate treatment should be initiated. In seriously ill patients, presumptive treatment may be started while diagnostic test results are pending. See appropriate chapters in Section 6: Disease-Specific Treatment or other relevant guidelines.

In the case of significant adverse effects from ARVs or other medications, use a substitute for the offending medications, if possible (without compromising the efficacy of the treatment regimen). In the case of serious or life-threatening medication toxicities (eg, lactic acidosis or abacavir hypersensitivity reaction), discontinue the offending medication (see chapter Adverse Reactions to HIV Medications).

After the workup and exclusion of life-threatening illness, symptomatic treatment can be considered. If nausea and vomiting are due to medications that are vital to the patient, and these complications are not life-threatening, antiemetic therapy may be the best treatment. Chronic therapy is not always necessary. Some patients obtain adequate relief by breaking the "nausea cycle" with effective antiemetics for 1-2 days and then establishing meals or snacks with medications. Patients with dehydration may require administration of fluids (oral or intravenous) to relieve nausea. For patients with chronic nausea resulting in weight loss, refer to a nutritionist for assessment and nutritional support.

Symptomatic treatment

Consider the following strategies for symptomatic treatment: Ginger capsules have proven effective in clinical trials for the management of pregnancy-related and chemotherapy-related nausea. Foods and beverages containing ginger (eg, tea, cookies, ginger ale, candies) may help provide relief. Promethazine (Phenergan) may be given as a 25-mg oral tablet or a 12.5-mg rectal suppository, every 8-12 hours as needed. Prochlorperazine (Compazine) may be given as a 5-mg or 10-mg oral tablet, or a 25-mg rectal suppository, every 6-8 hours as needed. Extended-release Spansule, 10 mg every 12 hours or 15 mg every morning, can also be considered. Lorazepam (Ativan) may be given as a 0.5 mg oral tablet one half hour before medications for symptoms of anticipatory nausea. Patients with anticipatory nausea develop significant nausea or vomiting when even thinking about medications or reaching for the medications. Dronabinol (Marinol) may relieve nausea, especially when nausea is accompanied by a loss of appetite. This remedy is best tolerated by patients who have tolerated inhaled marijuana. The starting dosage is 5 mg 2 or 3 times daily. 5-Hydroxytryptamine (5-HT3) receptor antagonists such as dolasetron (Anzemet) 50 mg and 100 mg, granisetron (Kytril) 1 mg, and ondansetron (Zofran) 4-mg, 8-mg, and 24-mg tablets are highly effective in relieving severe nausea and vomiting due to chemotherapy and other causes. However, access to these medications is limited by their cost. Their use should be considered a short-term strategy.