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T H E N AT I O N A L C O M P R E H E N S I V E CANCER NET WORK Clinica l Practice G u i d e l i n e s i n O n c o l o g y e s t a b l i s h recom mendat ion s for cu r rent ca re. Cli n icia ns must k now t he pa st che - mot herapy/ra d iot herapy t reat ment timeline. This will a llow the clinicia n to know if the patient is having brea k- through, delayed or refractor y nausea/ emesis. Categorica lly, antiemetic drugs control nausea a nd vomiting however they will only work with the right clini- ca l presentation. Patients who enter into hospice often present a f ter not tolerating the most r e c ent onc olo g ic a l t r e a t ment . T he mechanism of delay-nausea (>24hours) involves stimulation of neuroreceptors other than serotonin. Dopamine media- tions dominate this type of nausea. This leads to the benef it seen with phenothi- azines (chlorpromazine, promethazine) a n d b u t y r oph e n on e ( h a lop e r i d ol ). T he use of 5H T-3 a nt a gon ist s, such a s onda n set ron , is not benef icia l i n this phase of emesis control, as it lacks dopaminergic activity. The use of other dr ugs, such a s dexa metha sone, meto- clopramide, droperidol and olanzapine, may provide relief. Pharmacology D2 Antagonists, CTZ Phenothiazines D2AA,CTZ,VC 5HT3 Antagonists Anti-cholinergic Steroids Somato-statin ( peristalsis/ gastric secretion) Drug(s) Haloperidol* Meto-clopramide Olanzapine* Prochlorperazine Promethazine Chlropromazine Ondansetron Granisetron Dolasetron Scopo-lamine Patch* Dexamethasone* Octreotide* ADR (adverse drug reaction) EPS, dyskinesia, sedation EPS, dyskinesia, sedation HA, constipation Xero-stomia, sedation, blurred vision Weight gain, mood change, metabolic change Nausea, diarrhea Legend: D2 or D2AA (dopamine 2) antagonists, CTZ (chemoreceptor trigger zone), VC (vomiting center), 5HT3 (serotonin) antagonists, EPS (extrapyramidal symptoms), HA (headache) *Non FDA-approved, also called off-label indications Effectiveness of Antiemetic Drugs Requires Correct Clinical Presentation BY WAYNE H. GRANT, PharmD Intractable nausea and vomiting repre- sent a substantial source of physical and psychological distress for patients and caregivers. As the oral route of adminis- tration becomes limited to nonexistent, medication choices are scarce. Attempting rectal administration of various medica- tions becomes an appropriate route for some medications; unfortunately, infusion therapy may be required. The use of a subcutaneous continuous haloperidol infusion may provide the relief these patients deserve. Interactions: + SSR Is ca n lead to ma nic episodes (fluoxetine) + Anticholinergics and α-agonists can lead to tachycardia and hypertension + Antipsychotics reduced e˜cacy, higher risk of EPS (CYP1A2) Understa nding the patholog y a nd associated pharmacology will aid in devel- oping a plan of care which successfully addresses these distressing symptom. Dr. Wayne Grant is a clinical pharma- cist with Hospice of the Western Reserve in Cleveland, Ohio. ■ M D N E W S . C O M /// M D N E W S C L E V E L A N D /A K R O N / C A N T O N n M AY/J U N E 2 016 2 1