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Nausea Protocol

The goal of therapy with regards to the Nausea protocol is to have no nausea or vomiting (1). This is because it is easier to prevent nausea and vomiting as opposed to treating it. (1) The selection of drugs used depends on the emetogenicty of the chemotherapy drugs, which is the percentage of patients who will experience emesis if not treated (1). This is broken down to high (greater than 90%), high moderate (60-90%), low-moderate (30% to less than 60%), low (10% to less than 30%) and rare (less than 10%) (1).

5-HT3 Antagonists

Two different 5-HT3 antagonists are used in the Nausea protocol (1). They are ondansetron and granisetron (1). Several well conducted, randomized, comparative trials have failed to demonstrate any significant difference in efficacy or tolerability between these agents when used at the effective doses (1,4). The oral formulation of these drugs have comparable efficacy to the intravenous dosing for both the moderate and the highly emetogenic chemotherapy (1,2). Repetitive dosing is not superior to a single dose given immediately before chemotherapy (1). In general, 5-HT3 receptor antagonists are well tolerated with mild headache being the most frequently reported adverse event (15-20% of the patients) (2). Asthenia and constipation occur in 5-10% of patients and dizziness occurs in approximately 10% of patients treated IV and in 5% of patients who receive the oral formulation (2).

Ondansetron is used orally or IV for the prevention of nausea and vomiting that my result from emetogenic chemotherapy (2,3). For the prevention of chemotherapy induced nausea and vomiting, ondansetron hydrochloride injection should be diluted in 50 mL of 5% dextrose injection or 0.9% sodium chloride injection and infused IV over a period of 15 minutes (2). The oral dose is 8 mg 30 minutes before the administration of an emetogenic drug (2). Patients with renal impairment do not require a dosage adjustment of ondansetron (2,3). About 5% of the drug is eliminated by the kidneys and renal impairment is not expected to significantly alter the elimination of ondansetron (2,3). Ondansteron is metabolized extensively by hepatic CYP450 enzymes (2,3). The mechanism of action is through the blocking of the serotonin 5-HT3 receptors (2,3). These receptors are found centrally in the chemoreceptor trigger zone and peripherally in the vagal nerve terminals in the intestines (2,3). Emesis that occurs during chemotherapy and radiation therapy is associated with the release of serotonin from the enterochromaffin cells that are present in the small intestines (2,4). If these nerving endings in the intestines are blocked, it will prevent signals to the CNS. The onset of action is 30 minutes (2).

Granisetron is also indicated for the prophylaxis of chemotherapy related emesis (2,4). The usual oral dose is 2 mg once daily up to 1 hour before chemotherapy and the usual intravenous dose is 10 mcg/kg/dose given 30 minutes prior to chemotherapy (2). Dosing adjustment is not required in patients with hepatic impairment (2,3). As with ondansteron, this drug should be used with caution in patients that have congenital long QT syndrome or other risk factors for QT prolongation (2,3). This drug also is metabolized by CYP 3A4 enzymes (2,3). The duration of effect is usual up to 24 hours (3). The oral elimination is 6 hours and the intravenous elimination is 9 hours (2). Dexamethasone has antiemetic properties and is used as a prophylactic agent (2,4) It is given 10-20 mg 15-30 minutes before treatment on each treatment day orally or intravenously (2,4). The mechanism of its antiemetic activity is unknown (2,3). The onset of action is prompt and the duration of the metabolic effect may last for 72 hours (2). The time to peak serum levels is 1-2 hours orally and 8 hours intramuscularly(2). This drug is metabolized hepatically and thus renal adjustments are not necessary in the renal impaired patients (2). Side effects can include bradycardia, cardiac arrest, edema, depression, adrenal suppression, hyperglycemia, and abdominal distention (2). This medication should be used in caution in patients with glaucoma as increased intraocular pressure and cataracts have occurred with prolonged used (2). This drug is a substrate of CYP3A4 (2). Some interactions include antacids, which may decrease the bioavailability of dexamethasone, and thiazide diuretics, in which corticosteroids may enhance the hypokalemic effect of thiazide diuretics (2). Serum potassium, glucose and hemoglobin monitoring is recommended (2).

Aprepitant

This drug is for the prevention of chemotherapy induced nausea and vomiting (2,4). Specifically, it is used to prevent nausea and vomiting in moderately and high emetogenic chemotherapy (4). There is no dose adjustment needed in patients who are renally impaired (2). This medication should be given 1 hour prior towards antineoplastic therapy (2).The most common side effects (10%) include fatigue, constipation, weakness and hiccups (2). Hypotension, dizziness, and dehydration occur 1 to 10% of the time (2). This drug should be used in caution in patients that have severe hepatic impairment (2). Furthermore, there is high potential for interactions as it is a CYP 3A4 substrate (2). Some drug interactions include warfarin, in which aprepitant may decrease the serum concentration of warfarin (2). The mechanism of action of this drug is through the inhibition of substance P and the neurokinin 1 receptor (2). This also augments the antimetic activity of the 5-HT3 receptor antagonists and also corticosteroids (2). The effect is to inhibit the acute and delayed phases of chemotherapy induced emesis that may occur (2). The half life elimination is 9-13 hours and the time to reach peak plasma concentrations is 3-4 hours (2).

Metoclopramide

This medication is used for chemotherapy induced emesis prophylaxis (2,4). It is considered to have a low therapeutic index, so therefore the use is reserved for agents with low emetogenic potential or in patients that cannot tolerate the first line agents (4). In geriatric patients the dose should be started at the lower end of the recommended range (2). If the patient has a Clcr < 40 mL/ minute, half of the normal dose should be administered (2). Side effects can include fatigue, drowsiness, dizziness, confusion, depression, and insomnia (2). This medication should not be used in patients that have a history of seizures or GI obstruction (2). Therapy of more than 12 weeks of this agent should be avoided as the risk of tardive dyskinesia increases (2). The mechanism of action is through the blockage of dopamine receptors (at high doses) and also through the blockage of the serotonin receptors in the chemotrigger zone of the CNS (2). It also increases the response of acetylcholine of tissue in upper GI tract resulting in increased motility and accelerated gastric emptying without the stimation of gastric, biliary or pancreatic secretions (2). The onset of action is 30-60 minutes orally, or 1-3 minutes intravenously (2). The duration of effect is 1-2 hours regardless of route and the elimination is through the urine mainly (2).

Prochlorperazine

Prochlorperazine is an oral and a parental antimetic drug (2). It is used for the treatment and management of nausea and vomiting (2). The mechanism of action is through the blockage of the post synaptic dopamine receptors in the mesolimibc system (2). The dopamine blockade that is in the chemoreceptor trigger zone is responsible for the antiemetic effects (2). The duration of activity is 4-6 hours (2). Following the oral route, the onset of action is 30-60 minutes (2). Some side effects include hypotension, peripheral edema, dizziness, drowsiness and discoloration of the skin (2). This medication should be used with caution in patients who have renal impairment (2). The effects of sedatives may be potentiated when used with other drugs with sedative properties (2). This drug is primarily metabolized through hepatic means (2).

For high emetogencity drugs, during pre chemotherapy, one 5 HT3 anatogonist (ondansetron 8 mg po, or granisterone 1 mg po) should be used (1). Furthermore dextamethasone 8-12 mg po plus aprepitant 125 mg po should be used as well (1). For post chemotherapy of high emetogencity drugs, aprepitant 80 mg po daily x 2 days, plus dexamethasone 4 mg po evening of chemo, then 4 mg po BID x 2-5 days should be used (1). If needed, one of the following should be added: prochloroperazine 10 mg po every 4-6 hours PRN x 3-4 days or metoclopramide 1-40 mg po every 4-6 hours PRN x 3-4 days (1).

For high moderate to low moderate emetogencity drugs, one 5-HT3 antagonist (ondansetron 8 mg po, granisetron 1 mg po) plus dexamethasone 8-20 mg po should be used pre chemotherapy (1). For post chemotherapy, dexamethasone 4 mg po evening of chemo, then 4 mg po BID x 2-3 days (1). If needed, one of the following should be added: prochloroperazine 10 mg po every 4-6 hours PRN x 3-4 days or metoclopramide 1-40 mg po every 4-6 hours PRN x 3-4 days (1).

For low emetogenicity chemotherapy drugs, pre chemotherapy, dexamethasone 4-12 mg po is preferred (1). Alternatives include prochloroperazine 10 mg po or metoclopramide 20-40 mg po (1). For post chemotherapy, dexamethasone 4 mg BID for up to 2-3 days or prochloroperazine 10 mg po every 4-6 hours PRn x 3-5 days or metoclopramide 1-40 mg po every 4-6 hours PRN x 3-4 days (1). In drugs that have rare emetogenic potential, prophylactic treatment is not mormally required for pre chemotherapy (1). Post chemotherapy can include the use of prochloroperazine 10 mg po every 4-6 hours PRN x 3-4 days or metoclopramide 10-40 mg po every 4-6 hours PRN x 3-4 days (1).

References

  1. BC Cancer Agency. Guidelines for Prevention and Treatment of Chemotherapy-Induced Nausea and Vomiting in Adults [Online]. 2011 Mar 1 [cited 2012 Jan 29]; Available from: http://www.bccancer.bc.ca/NR/rdonlyres/8E898B5D-3F12-4623-8E32-5B3C429C58F7/49708/SCNAUSEA_Protocol_1Mar2012.pdf
  2. Repchinsky C, editor. Ondansetron, granisetron, dexamethasone, aprepitant, metoclopramide, prochlorperazine. In: Compendium of Pharmaceuticals and Specialties [online version (e-CPS)]. Ottawa: Canadian Pharmacists Association; 2005 [cited 2012 Jan 27]. Available from: URL: http://e-cps.pharmacists.ca/CPHA/main.htm
  3. Hesketh PJ. Chemotherapy-induced nausea and vomiting. N Eng J Med 2008;358:2482.
  4. Roila F, Herrstedt J, Aapro M, et al. Guideline update for MASCC and ESMO in the prevention of chemotherapy-and radiotherapy-induced nausea and vomiting: results of the Perugia consensus conference. Ann Oncol 2010; 21(5):v232.

Disclaimer

This information is presented for informational purposes only and is not meant to be a substitute for advice provided by qualified health care professionals. You should contact your qualified health care provider if you have or suspect any health problems. This article is not intended to provide medical advice for its readers


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