Nausea antiemetics

Dronabinol (tetrahydrocannabinol), the active principle from cannabis and synthetic cannabinoids, nabilone and levonantradol are effective in treating nausea and vomiting in cancer chemotherapy. The mode of action is unclear but appears to involve cannabinoid CBi receptors. Cannabinoids have been shown to reduce acetylcholine release in the cortex and hippocampus, and have been suggested to inhibit medullary activity by a cortical action. Inhibition of prostaglandin synthesis and release of endorphins may also be involved in the antiemetic effect. A review of trials of dronabinol, nabilone or levonantradol concluded that while the cannabinoids were superior to placebo or dopamine receptor antagonists in controlling emesis... 

It is important to note diat antivertigo dragp are essentially antiemetics because many of these preparations, whedier used for motion sickness or vertigo, also have direct or indirect antiemetic properties. They prevent the nausea and vomiting diat occur because of stimulation of die vestibular apparatus in the ear. Stimulation of diis apparatus results in vertigo, which is often followed by nausea and vomiting. 

Antiemetic—to lessen the incidence of nausea and vomiting during the immediate postoperative recovery period. 

Antineoplastic drugs are potentially toxic and their administration is often associated with many serious adverse reactions. At times, some of these adverse effects are allowed because the only alternative is to stop treatment of the malignancy. A treatment plan is developed that will prevent, lessen, or treat most or all of the symptoms of a specific adverse reaction. An example of prevention is giving an antiemetic before administering an antineoplastic drug known to cause severe nausea and vomiting. An example of treatment of the symptoms of an adverse reaction is the administration of an antiemetic and intravenous (IV) fluids and electrolytes when severe vomiting occurs. 

Standardised preparations of cannabinoid agonists are available for therapeutic use in some countries [238]. Dronabinol (Marinol ), an oral preparation of A -THC (67), is used clinically as an appetite stimulant in AIDS patients and an antiemetic in cancer chemotherapy. A synthetic analogue of (67), nabilone (Cesamet ), (381), is also used to suppress nausea and vomiting in cancer chemotherapy. 

Stimulation of dopamine (D2) receptors in the CTZ leads to nausea and vomiting (Fig. 17-1). Phenothiazine antiemetics... 

Gan TJ, Meyer T, Apfel CC, et al. Consensus guidelines for managing postoperative nausea and vomiting. Anesth Analg 2003 97 62-71. Gralla RJ, Osoba D, Kris MG, et al. Recommendations for the use of antiemetics evidence based clinical practice guidelines. J Clin Oncol 1999 17 2971-2994. 

Apomorphine is approved for acute off episodes in patients with advanced stages of PD. The onset of effect is within 10 to 20 minutes and the duration of effect is about 60 minutes. It requires premedication with an antiemetic because it causes nausea and vomiting. Antiemetics that block central dopamine worsen the symptoms of PD, and 5-HT3 antagonists, such as ondansetron, can aggravate PD-related hypotension. Trimethobenzamide (300 mg three times daily) should be... 

Hydration, heating pads, relaxation, and distraction Stool softener and/or stimulants for constipation Antihistamine for itching Antiemetics for nausea or vomiting... 

The answer is e. (Hardmanr p 930.) All the drugs listed in the question are used as antiemetics. Chlorpromazine is a general antiemetic, used orally, rectally, or by injection for the control of nausea and vomiting that is caused by conditions that are not necessarily defined. Ondansetron is indicated in the oral or intravenous route for the prevention of nausea and vomiting caused by cancer chemotherapy Diphenhydramine and dimen-hydrinate are used orally for the active and prophylactic treatment of motion sickness. Scopolamine is a transdermal preparation used in the prevention of motion sickness. The drug is incorporated into a bandage-like... 

The overall goal of antiemetic therapy is to prevent or eliminate nausea ... 

Metoclopramide is used for its antiemetic properties in patients with diabetic gastroparesis and with dexamethasone for prophylaxis of delayed nausea and vomiting associated with chemotherapy administration. 

Nausea and vomiting that occur within 24 hours of chemotherapy administration is defined as acute, whereas when it starts more than 24 hours after chemotherapy administration, it is defined as delayed. The emetogenic potential of the chemotherapeutic agent or regimen (see Table 27-2) is the primary factor to consider when selecting an antiemetic for prophylaxis of CINV. 

Chlorpromazine, prochlorperazine, promethazine, methylprednisolone, lorazepam, metoclopramide, dexamethasone, or dronabinol may be used for adult patients. Around the clock dosing should be considered. The choice of specific agent should based on patient specific factors, including potential for adverse drug reactions, and cost. SSRIs are effective for breakthrough nausea and vomiting but they are not superior to the less expensive antiemetics above. 

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