when are antiemetics prescribed
only prescribed when the cause of vomiting is known because otherwise, they may delay diagnosis, particularly in children
name some antihistamines that can be for nausea + vomiting
cinnarizine, cyclizine, promethazine
which drugs can be used for chemotherapy-induced and radiation-induced nausea and vomiting
- Prochlorperazine, chlorpromazine (the phenothiazines)
- Dexamethasone
which antipsychotics can be used for the relief for nausea + vomiting in palliative care
haloperidol [unlicensed use] and levomepromazine
how does Metoclopramide act as an antiemetic
it acts directly on the gastric smooth muscle stimulating gastric emptying
what is the advantage of Domperidone as an antiemetic
less likely to cause central effects, such as sedation and dystonic reactions compared to metoclopramide + the phenothiazines (e.g chlorpromazine, prochlorperazine)
This is because it does not readily cross the blood-brain barrier
when can antiemetics be used during pregnancy
Antiemetics should be considered for women with persistent symptoms where self-care measures have been ineffective.
self-care advice (such as rest, oral hydration and dietary changes)
TRUE OR FALSE
ginger may be helpful for mild to moderate nausea during pregnancy
true
name some antiemetics that can be used during pregnancy
- drug treatment options: chlorpromazine , cyclizine, metoclopramide prochlorperazine, promethazine and ondansetron.
- choice depends on patient preference. if response to a drug after 24 is inadequate, switch to a different one in a different therapeutic class
what is Hyperemesis gravidarum
a more serious condition of severe nausea + vomiting which requires regular antiemetic therapy, intravenous fluid and electrolyte replacement, and sometimes nutritional support.
why must thiamine supplement be considered during pregnancy
to reduce the risk of Wernicke’s encephalopathy (a neurological disease that results in confusion, the inability to coordinate voluntary movement (ataxia) and eye (ocular) abnormalities)
what are the risk factors for postoperative nausea + vomiting
- female sex
- younger age
- non-smokers
- a history of postoperative nausea and vomiting or motion sickness
- use of opioids
risk of nausea + vomiting also depends on: the anaesthetic used, and the type and duration of surgery
how are antiemetics used for Postoperative nausea and vomiting
A combination of two or more antiemetic drugs that have different mechanisms of action is often used in patients with risk factors for postoperative nausea and vomiting
- Drugs used include 5HT3-receptor antagonists (e.g. granisetron, ondansetron), dexamethasone, droperidol and haloperidol
which antiemetics can be used for motion sickness
- Hyoscine hydrobromide
- antihistamines such as cyclizine, promethazine
note Domperidone, metoclopramide hydrochloride, 5HT3-receptor antagonists, and the phenothiazines (except promethazine—an antihistamine phenothiazine) are ineffective in motion sickness
what is Ménière’s disease
Ménière’s disease is an ear condition that can cause sudden attacks of vertigo (a spinning sensation).
- Patients presenting with symptoms of Ménière’s disease should be referred to an ear, nose, and throat specialist to confirm the diagnosis.
