PEG vs Docusate

Dec 5, 2016

By Trevor Shewfelt, Pharmacist at the Dauphin Clinic Pharmacy

It was Remembrance Day. I was trying to get to CKDM to record a pharmacy feature and then get into work. I wasn't being disrespectful. Pharmacies get a Remembrance Day exemption to open because even Veterans might need medication on November 11. Doris and Emily were trying to leave town for Emily's hockey game in Carman. I'm not sure if playing hockey on Remembrance Day is disrespectful or not. We all met at the back door, and suddenly everyone looked around and asked, "Where is Eric?" A quick look in the garage determined his bike was missing, so he could be anywhere. No, Eric hadn't told anyone where he was going. Yes, he was told he had to be in the vehicle with his sister for the drive to Carman. No, there was no answer when we phone his friend Brodie's house. Yes, I was going to be late for CKDM and for work. Yes, Emily was going to be late for her hockey game. Yes, we really were going to drive around Dauphin looking for him. No Emily, we can`t just all leave and see if he came back when we all get home. Suddenly a red bike pulled into the driveway. Eric hopped off and said, ``You know what`s weird? 7-11 is closed!"

They weren't as good as Slurpee's, but I used to make milk shakes for residents of St. Paul's Care Home. Okay, we called them milk shakes. The residents probably had other names for them. We would mix milk of magnesia, which is a white liquid and senna syrup, which is a dark brown liquid. The result kinda looked like a chocolate milk shake. It didn't smell great and it didn't taste great, but it did help care home residents poop. I don't think I've made up one of those milk shakes in 15 years now, and I really can't blame the residents for not liking them.

In care homes, often we have people on medications that make them constipated. And often care home residents can't do the simple things the rest of us can do to prevent constipation. Simple constipation is usually caused by lifestyle. Ignoring the urge to empty your bowels, and a low fibre diet often contribute to constipation. Other lifestyle factors like not drinking enough fluid, not eating breakfast, and not exercising may lead to constipation as well. The elderly are constipated more often than younger people, and women are constipated more often than men. Constipation can cause different symptoms in different people. Some commonly reported symptoms are difficulty and straining in passing a stool, uncomfortable abdominal bloating, cramping, headache, and lack of interest in food.

Prevention of simple constipation should begin by using non-drug measures. These measures include eating 15-30g of food fibre per day. This is actually quite difficult to achieve, so 10 g of fibre per day is a good minimum to strive for. A person should drink 6-8 glasses of water per day. There has been some debate lately if you really need that much water per day. In this case water really does help the fibre do its job. A person should respond to the urge to empty the bowels as soon as possible, but don't strain when on the toilet. Regular, moderate exercise is also good for you in many ways. Some of the reading I did said exercise is good at preventing constipation, but that is not definitive. But, as exercise is good for you in so many other ways, it is a good recommendation.

Constipation in the care home is so common, we often have people on chronic constipation medications. Docusate sodium and docusate calcium are very common choices. They are both stool softeners, and have been used in hospitals and care homes for over 50 years. Docusate is a surfactant, so that is very similar to soap. It breaks the surface tension of the stool which lets water in. That softens the stool, and makes it easier to pass. Or at least that is what we were taught in pharmacy school.

It seems lately that when the docusate studies were looked at, they weren't very well done. One docusate study done in 1968 only had 15 elderly patients in it. A study in 1998 compared docusate to psyllium in 170 patients. The patients on the psyllium did better helping with constipation. In 2010 researchers actively looked for docusate studies and only found one double blind placebo controlled trial that they thought was done well enough to write about. And that study only had 22 people in it. The Canadian Agency for Drug and Technologies in Health (CADTH) only found 5 relatively poorly done studies on docusate from 2004 to 2011. And unfortunately, those studies didn't find docusate to be any better than placebo at decreasing constipation or constipation symptoms.

What should we use instead of docusate? In the care homes, we are using PEG 3350 now. It has brand names like Restoralax and Lax-a-Day. It is a white powder you dissolve in water and drink. It has almost no taste, so much nicer to take than those old milkshakes of milk of magnesia and senna syrup.

PEG 3350 is an osmotic laxative. That means it draws water into the bowl, and help everything just flush along. It is safe to use daily. It is safe to use in children, adults, the elderly and pregnant women. So, this is the end of the story, right. Docusate has little to no evidence, PEG 3350 does, let's just switch everyone, right? Well, in the care homes anyway, it is a little more complicated. You see, at the moment, Manitoba Health will pay for docusate, but they will not pay for PEG 3350. If we want to switch your Auntie Lilly in a care home from docusate to PEG 3350, we will have to talk to the family first. We will have to say, "The constipation medication Auntie Lilly is on now might not work, but it is free. We want to switch her to a constipation medication that will work, but you'll have to pay for every month. What would you like to do?" Depending on how much PEG 3350 the patient needs, it might cost $20 to $40 per month. That much money is mildly inconvenient for some families, and a real burden on others. So, it will be fantastic when Manitoba Health catches up to accepted clinical practice and starts paying for PEG 3350. It would be great if everyone in the care home could afford the most appropriate constipation medication.

Eric was surprised by the combination of anger, confusion, and relief that he was greeted with when he got home. He was also still confused by 7-11 being closed. I guess I'm a bad parent by not teaching him the proper respect and decorum on Remembrance Day. And the big question, why had he suddenly left the house without telling anyone and ridden across town to 7-11? Did he suddenly have an irresistible urge for a Slurpee brain freeze? No, he needed to buy an Xbox gift card. That Xbox gift card would have allowed him to buy and download a video game he needed. He needed that game because he couldn't bare the idea of a 3 hour car ride to Emily's hockey game in Carman without it. At least that is his biggest worry. Not explaining to a family why Manitoba Health wants to pay for a med that probably won't work and won't pay for one that probably will.

As always if you have any questions or concerns about these or other products, ask your pharmacist.

The information in this article is intended as a helpful guide only. It is not intended to be used as a substitute for professional advice. If you have any questions about your medications and what is right for you see your doctor, pharmacist or other health care professional.

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