Pharmacologic Profile

General Use

Phenothiazines, granisetron, metoclopramide, ondansetron, and palonosetron are used to manage nausea and vomiting of many causes, including surgery, anesthesia, and antineoplastic and radiation therapy. Aprepitant, fosnetupitant, and netupitant are used specifically with emetogenic chemotherapy. Scopolamine and meclizine are used almost exclusively to prevent motion sickness. Doxylamine/pyridoxine is used exclusively for the treatment of nausea and vomiting during pregnancy that has not responded to conservative management.

General Action and Information

Contraindications

Previous hypersensitivity.

Precautions

Use phenothiazines cautiously in children who may have viral illnesses. Use granisetron, palonosetron, and ondansetron with caution in patients with QT interval prolongation.

Interactions

Additive CNS depression with other CNS depressants including antidepressants, antihistamines, opioid analgesics, and sedative/hypnotics. Phenothiazines may produce hypotension when used with antihypertensives, nitrates, or acute ingestion of alcohol. Granisetron, palonosetron, and ondansetron may ↑ the risk of serotonin syndrome when used with other serotonergic agents. Aprepitant, fosnetupitant, and netupitant have numerous drug interactions with CYP450 agents. See individual drugs.

Nursing Implications

Assessment

• Assess nausea, vomiting, bowel sounds, and abdominal pain before and following administration.
• Monitor hydration status and intake and output. Patients with severe nausea and vomiting may require IV fluids in addition to antiemetics.

Implementation

• For prophylactic administration, follow directions for specific drugs so that peak effect corresponds to time of anticipated nausea.

Patient/Family Teaching

• Advise patient and family to use general measures to ↓ nausea (begin with sips of liquids and small, nongreasy meals; provide oral hygiene; remove noxious stimuli from environment).
• May cause drowsiness. Advise patient to call for assistance when ambulating and to avoid driving or other activities requiring alertness until response to medication is known.
• Advise patient to make position changes slowly to minimize orthostatic hypotension.

Evaluation/Desired Outcomes

• Prevention of, or reduction in, nausea and vomiting.