Antiemetics and Emetics

Nausea and Vomiting Emetic center of the brain is stimulated Goal is to empty the GI tract of irritants and toxins Symptoms not a disease

Nausea and Vomiting Causes are varied - motion sickness - morning sickness - intense pain - chemical toxins - emotional stress

Nausea and Vomiting Usually harmless but can signal a serious condition - increased intracranial pressure - concussions - encephalitis - meningitis - intestinal blockage - appendicitis - migraine headaches - brain tumors

Concerns Risk for aspiration Risk for dehydration or electrolyte imbalances Children, the elderly, and those with chronic illnesses are more at risk of complications

Emetics Agents that induce vomiting Used in overdoses Example Ipecac syrup Inappropriate use Clients with bulimia

Antiemetics Five categories of antiemetics Anticholinergics Antihistamines Neuroleptic agents Prokinetic agents Serotonin blockers

Anticholinergics and Antihistamines Bind to and block acetylcholine receptors Prevent nausea stimuli from being transmitted Scopolamine patch – motion sickness prevention

Anticholinergics and Antihistamines Block histamine (H2) receptors Prevent cholinergic stimulation Antivert for motion sickness, vertigo Promethazine (Phenergan) for nausea/emesis Use caution with IV route

Side Effects of Antihistamines and Anticholinergics Dry mouth Urinary retention Blurred vision, dizziness Use with caution in patients with benign prostatic hypertrophy and narrow-angle glaucoma

Neuroleptic and Prokinetic Agents Neuroleptic agents Bind to the dopamine receptors and block action Limit dopamine activity Prokinetic agents Block dopamine Stimulate acetylcholine to increase gastric emptying

Serotonin Blockers Zofran Block serotonin receptors in the gastrointestinal tract Block serotonin receptors in the central nervous system (emetic center) Used often when antineoplastic agents are being given

Serotonin Blockers Prevents transmission of afferent visceral and chemoreceptor triggers Most common agents for patients on chemotherapy Also used for patients with migraines, gastroenteritis, and postoperatively

Nursing Considerations Evaluate effectiveness of therapy If inducing vomiting, main goal is determination of toxic agent to determine if vomiting is appropriate and other treatment needs Ensure an adequate airway

Nursing Considerations Prevention is better than cure – anticipate when possible Assess patient for reason behind nausea/vomiting Prevent aspiration