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CC Nov 2016 Opioid-induced constipation

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echoecho's version from 2016-11-27 21:01

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Question Answer
Opioid-induced constipation (OIC) affects about ____% of patients who take opioid for no malignant pain and up to ____% of all patients taking opioids?50%; 90%
What is OIC the consequence of?Receptor stimulation in the GI tract
What is the effect of opioids on the GI tract? 1) delay gastrointestinal transit time 2) increases pyloric, ileocecal and anal sphincter tone. 3) enhance non-propulsive circular muscle contractions which facilitates fluid resorption thus not only are the sphincter having increased gone but the stools are harder
List the treatment option for OIC?1) increase physical activity and fluid intake when opioids are started, although these intervention have not been proven to prevent OIC. 2) stimulants such as senna (Senokot) and bisacodyl (generic, > 20 brand names) are often initiated (stimulants increase motility but can also expected cause cramping and electrolyte disturbances) 3) stool softened sre inadequate as sole therapy. 4) polyethylene glycol (Miralax) is well tolerated osmotic agent that appears to be as effective as other laxative classes (despite laxative use, fewer than 50% of patients achieve a desired effect)
How do oral opioid receptor antagonists counter OIC?by directly blocking effects in the GI tract
Naloxone (Narcan) diminishes OIC. Why is it unlikely to affect the central opioid receptors?due to limited penetration across the blood-brain barrier
*** True or false? Naloxone's ability to reverse analgesia is dose-related and unpredictable?true
What medication is an oral, pegylated form of naloxone indicated for OIC in noncancer patients?Naloxegol (Movantik)
Is use of Naloxegol (Movantik) in cancer patients off-label? Does this modified naloxone have minimal CNS penetrationyes; yes
Regarding oral Naltrexon (Revia), why is it not used for treating OIC? It's improved kinetic profile contributes to its role in treating what?1) it's absorption precludes it from being used to treat OIC 2) treating alcohol and opioid dependence
What are PAMORAs?newer peripheral-acting mu-opioid receptor antagonists designed to target OIC without compromising pain control
What medication is approved in subcutaneous form for patients with noncancer pain or advanced illness?Methylnaltrexone (Relistor)
What diminishes Methylnatroxone's ability to cross the blood-brain barrier and interfere with analgesia?low lipophilicity
Regarding the chloride channel activator lubiprostone (Amitiza). When did it receive a OIC indication? What are some disadvantages of this medication?1) 2013 2) has not demonstrated benefit with all opioid classes 3) has potential severe side effects (chest pain, dyspnea, abdominal pain)
*** SUMMARY = Opioid-induced constipation affects up to ____% of all patients taking opioids?90%
*** SUMMARY = Name an osmotic agent that are well tolerated?polyethylene glycol (Miralax)
*** SUMMARY = List 2 medications that should be avoided when treating OIC?1) Naloxone 2) Naltrexone
*** SUMMARY = List 2 medications that are effective and safe in treating OIC?1) Methylnaltrexone (Relistar) 2) Naloxegol (Movantik)
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