Pharm, part 37: Gastrointestinal Medications - Laxatives

by Cathy Parkes September 10, 2021 Updated: September 14, 2021

Full Transcript

Hi. I'm Cathy with Level Up RN. In this video I'm going to continue my coverage of gastrointestinal medications. Specifically, I'll be covering laxatives. At the end of this video I'll be giving you guys a little quiz to test your knowledge of some of the key facts I'll be covering in this video. So definitely stay tuned for that. If you have our Pharmacology Second Edition Flashcards, definitely pull those out so that you can follow along with me.

So as we talk about laxatives, many times laxatives are prescribed in order to treat constipation. When a patient has constipation, we're going to want to provide additional teaching versus just giving them laxatives on ways they can prevent constipation, this includes increasing their fluid intake as well as increasing their fiber intake. We also want to encourage our patients to get up and move around. So increase their mobility because that can also help to stimulate peristalsis.

First up, we have our stool softeners, which includes docusate sodium and docusate calcium. These medications are used to prevent constipation. They work by drawing water into the stool, which helps to soften the stool. Side effects can include mild cramping, as well as diarrhea. We want to encourage our patient to take this medication with a full glass of water. And our cool chicken hint for remembering these medications is the doc said if you ate more fiber, you wouldn't need docusate to soften your stool.

All right. Next we have our bulk forming laxative, which include psyllium and methylcellulose. So these medications are used for constipation, as well as the management of chronic watery diarrhea. The mode of action of these bulk forming laxatives is that they combine with water in the intestines to soften the stool and increase the bulk of the stool. Side effects can include mild cramping, as well as nausea or vomiting. In terms of administration of this medication, we want to encourage the patient to take psyllium or methylcellulose with a full glass of water and then drink another glass of water after that.

Next we have our stimulant laxatives, which include bisacodyl and sennosides. These medications are used for constipation, as well as bowel prep prior to a surgery or procedure. They work by stimulating peristalsis. Side effects can include cramping, as well as nausea and vomiting. We want our patient to take their medication with a full glass of water. Our cool chicken hint for remembering at least one of these medications is bisacodyl will help you do your business. So your BM.

All right. Next let's talk about osmotic laxatives, which include magnesium hydroxide, magnesium citrate, and polyethylene glycol, which is Miralax. These medications are used for constipation, as well as bowel prep prior to a surgery or procedure. They work by drawing water into the intestine, as well as stimulating peristalsis. Side effects can include cramping, bloating, and diarrhea. And if we're talking about administration of magnesium hydroxide or magnesium citrate, then it can actually cause hypermagnesemia, so elevated magnesium levels. So as the nurse, you need to monitor your patient's magnesium levels if they're on one of these two medications. There's another osmotic laxative, which is a lactulose, which I've always pronounced as lactalose, but apparently it's lactulose. Lactulose is used for the treatment of hepatic encephalopathy due to a buildup of ammonia in the body. So this occurs when a patient has liver dysfunction and the body's not getting rid of toxins, including ammonia, and that ammonia goes up to the brain and causes confusion. So we would give the patient lactulose, which helps to lower the PH in the colon, which in turn promotes excretion of ammonia. So it helps to bring those ammonia levels down.

So our little cool chicken hint here for remembering lactulose is that lactulose will cause you to lose stool as it gets rid of excess ammonia. So when you look at the spelling of lactulose, it ends in that L-O-S-E, which will help you to remember that it will help you lose stool and get rid of that ammonia.

All right. That is it for osmotic laxatives. Time for a quiz. Question number one, what instructions should you provide your patient who is taking psyllium? You should tell them to take it with a full glass of water and then drink another glass of water after that. Question number two, what laxatives can cause hypermagnesemia? The answer is magnesium hydroxide and magnesium citrate. Question number three, what laxative is used to treat hepatic encephalopathy? The answer is lactulose. All right. I hope this quiz has been helpful. Hopefully, the whole video was helpful. If so, be sure to leave me a comment. I would love to hear from you. Take care and good luck with studying.


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