*Ask A Pharmacist, Answers Always Free
What are they: They are a variety of suppositories and enemas on the market for constipation. They have the quickest onset of action of any of the laxatives.
What do they do: They all work by either local rectal stimulation or by distending the colon with excess fluid inducing evacuation of the bowels. Suppositories typically work in 15-60 minutes while enemas work in less than 10 minutes.
Glycerin suppositories and enemas (Fleet products)
Bisacodyl suppositories (Dulcolax)
Mineral oil suppositories and enemas
Tap water enemas
Sodium phosphate enemas (Fleet products)
How to use:
Suppositories are used as needed. Since they cause local irritation, they should be used sparingly. Sometimes they are easier to insert if you moisten them with water immediately prior to administration.
For the enemas, they typically come in unit doses so one bottle would be one dose. Here are some typical directions for enema products:
The correct position would be to lie on your left side (not your back!) with your top knee bent. You can also kneel down with the head and chest lowered.
Insert the enema tip into the rectum gently with the tip pointing towards the belly button. The enema tip can sometimes be easier to insert if slightly lubricated. Squeeze the bottle of product until almost all of the liquid is emptied. Try to retain the enema liquid for around 3-5 minutes. At this point the urge to evacuate will be strong.
Side effects: Discomfort upon insertion, watery loose stools.
When not to use: Fleet products have been associated with hyperphosphatemia (high phosphate levels). It should never be used in patients with kidney problems.
Notes: Suppositories are typically more predicable in terms of knowing when you will evacuate your bowels. Enemas can cause discomfort in people and the onset of the urge to go to the bathroom can be almost immediate.
What are they: There is one lubricant laxative and it is mineral oil. It is a fatty substance used to lubricate the GI tract and stool.
What do they do: Mineral oil lubricates and softens the stool. It works in approximately 6-8 hours.
Products: Mineral oil
How to use: 15-45 ml per day
Side effects: Loose oily stools, mild abdominal cramps, rectal leakage.
When not to use: Mineral oil should not be taken with stool softeners as this is a major interaction. Stool softeners such as docusate actually facilitate absorption of mineral oil systemically. This can cause wide spread inflammation in the intestines, liver and other areas of the body.
Notes: Mineral oil is the only laxative indicated for actual fecal impaction (where your stool is physically stuck in your GI tract). Do not administer mineral oil at night before bedtime and do not use for more than one week at a time. Also, mineral oil could possibly cause decreased absorption of certain fat soluble vitamins such as vitamin A and D. It should be administered a few hours apart from meals.
What are they: Saline laxatives combine what the other laxatives offer. They increase fluid in the stool AND they stimulate movement in the GI tract.
What do they do: All of the products draw water into the intestines and increase pressure in the intestines. The increase in pressure in the GI tract promotes movement of fecal matter. They work the fastest out of all the laxatives (not including suppositories or enemas). The onset of action is typically 30 minutes to a few hours.
Magnesium Citrate liquid
Magnesium Hydroxide (Milk of Magnesia)
Sodium Phosphate (Fleet Phospho-soda)
How to use:
Magnesium Citrate: 5 ounces per dose, up to two doses per day
Magnesium Gydroxide: 15-30 ml once to twice daily
Sodium Phosphate - One tablespoon of powder in 4 to 8 ounces of liquid. The product also comes in a liquid form. Follow the package instructions for the liquid form.
Side effects: The saline laxatives have the most possible side effects/contraindications for patients. All of them should never be used in patients with kidney problems. The elderly typically have decreased kidney function so they should be used cautiously in that age group. They also tend to cause the most GI discomfort such as bloating and cramping. Fleet phospho-soda specifically has been associated with kidney problems because of the strong laxative effect and the phosphate that the drug contains.
When not to use: Patients with fluid/electrolyte disturbances, and those with kidney problems.
Notes: The saline laxatives are typically the quickest acting laxatives that are taken by mouth on the market. They should be used sparingly however due to the fluid loss and electrolyte disturbances they can induce.
What are they: Osmotic laxatives are not absorbed into the body. They either bind water or draw in water to the colon allowing fluid to be retained in the stool.
What do they do: Osmotic laxatives are named as such because they increase the amount of fluid in the colon. They are not absorbed into the body and pretty much just run through your GI tract. They are not known as stimulant laxatives because they don't stimulate the movement of the GI tract like the stimulant laxatives do. They soften stool consistency and usually increase stool frequency. Their onset is typically 1-3 days although higher doses (such as those used for colonoscopy prep) work considerable faster.
Polyethylene Glycol 3350 (Miralax)
How to use:
Polyethylene Glycol (Miralax): One capful (around 17 grams) mixed with 8 ounces of liquid and drink once daily.
Sorbitol: 15-30 ml by mouth once to twice daily.
Side effects: abdominal cramps, flatulence, diarrhea, bloating.
When not to use: Kidney disease. Sorbitol is actually a sugar alcohol (Just like what is used to sweeten many chewing gum products) and some people have sensitivities to these. Both products should be used cautiously in patients with electrolyte imbalances.
Notes: Cannot cause dependency like the stimulant laxatives. Diarrhea is typically more common with sorbitol products than with the polyethylene glycol products. Lactulose is another osmotic laxative but it is only available via prescription.
What are they: Stimulant laxatives promote (or stimulate) your gastrointestinal tract to empty its contents more quickly.
What do they do: These drug products produce their laxative effect by stimulating movement in the GI tract (known as peristalsis which is a rhythmic contraction and relaxation of muscles). They are also thought to increase electrolytes in the GI tract promoting water accumulation and thus a laxative effect occurs. Stimulant laxatives tend to work in about 6-12 hours.
Products: Bisacodyl (Dulcolax, Ex-lax), sennosides (Senna).
How to use:
Bisacodyl: 1-3 tablets per day
Sennosides: 2-8 tablets per day
Bisacodyl in most cases works a little faster than sennosides. It is usually recommended to take your dose in the evening and will hopefully produce a bowel movement in the morning. If you take the products on an empty stomach they will work faster.
Side effects: Cramps, loose stools, mild nausea. Long term use can cause excess fluid and electrolyte loss. Long term use can lead to a dependence causing constipation when the product is not taken.
When not to use: As mentioned above, the stimulant products can cause excess fluid loss and alter electrolytes. Patients with low sodium or potassium should ask a doctor before taking these or those with various heart conditions. The elderly are most likely to have fluid problems.
Notes: Sennoside products are considered gentle or "mild" laxatives. They typically don't work quite as quickly as bisacodyl but may cause less cramping. In terms of dependence, consistent use means more than 3 times a week for a considerable amount of time. If used chronically, they can cause what is known as cathartic colon where the absence of a laxative causes constipation.
What are they: Stool softeners are a safe option to soften the stool.
What do they do: Technically, stool softeners are called surfactants. They decrease the surface tension of the oil/water in the stool which softens the fecal matter by allowing more water in the stool. They are not considered laxatives because they promote natural defecation and are not stimulants. It usually takes one to three days of therapy to notice benefits.
These products are pretty much interchangeable. They go by various brand names including Colace, Kaopectate stool softener and Surfak.
How to use: Typically these are used more as a preventative than as a treatment for constipation but they can still be effective for hard to pass stools or with stools that cause excess straining. The typical dosage is 1 tablet/capsule up to three times a day of either product.
Side effects: They are generally very well tolerated. Rarely they may cause the stools to become too loose and cause diarrhea.
When not to use: In most cases, stool softeners are a safe choice. Docusate sodium does contain a small amount of sodium. Those really concerned with sodium intake can consider docusate calcium.
Notes: Stool softeners are especially good for patients that need to avoid straining such as those with hemorrhoids, certain heart conditions or those who have gone through a recent surgery.
What are they: Bulk forming laxatives are typically first line treatment for constipation. They are also called fiber laxatives.
What do they do: Bulk forming laxatives increase the bulk of the stool and speeds up how quickly things run through your GI tract
Products: Not all fiber is created equal. Typically you want to look for a "soluble fiber" as they have more evidence than insoluble fiber for treating constipation. Soluble fiber products are available as:
Metamucil (Psyllium fiber)
Citrucel (Methylcellulose fiber)
Fibercon (Polycarbophil Fiber)
How to use: Typically one measured dose (as indicated on the package) up to three times daily. This can vary based on your desired fiber intake. Fibercon and Citrucel are available as tablets. Follow the dosing instruction on the package.
Side effects: Bloating, gas
When not to use: Do not use if you have difficulty swallowing, are on a fluid restricted diet, have an obstruction in the GI tract or if you have or had heart failure/kidney failure. Also, the sugar free version of products typically contains aspartame and should not be used in patient with phenylketonuria.
Notes: As mentioned before, not all fiber is created the same. Citrucel (methylcellulose) is known to cause less bloating and gas in patients than the other fiber options. However, Metamucil (psyllium) has the positive attribute of lowering blood cholesterol and glucose levels in people. This evidence is not there for Citrucel. Lastly, Fibercon (Polycarbophil) contains a significant amount of calcium (~120 mg per tablet). It should not be used in patients with heart failure or those looking to restrict calcium from the diet.
Constipation is one of the most common medical problems that patients treat over the counter without seeking medical advice. In most cases, this is fine! This is one of the reasons why there are over the counter products available for self treatment. The most important thing to know is when to see a doctor regarding the problem. This list isn't all inclusive, but here are some general guidelines on when self treatment should be avoided:
The last bullet is especially important. There are many different possible causes of constipation including diet, physical activity and possible medication problems to name a few. Recurring constipation should be treated by a physician so they can determine the cause and take appropriate action.
In this guide we will focus on the over the counter products to help manage constipation. There are a few prescription products but we want to focus on the self treatment. Hopefully this guide will add some insight and give information for those seeking help!
Constipation is both a common symptom and problem affecting millions of people. Due to the nature of the problem, some can find it embarrassing to seek help or advice concerning the issue. It shouldn't be that way! It is important to understand what is causing the problem and what treatment options you have available to you.
What is constipation?
This seems like an easy answer, but it's good to have a definition clarified. Constipation is typically associated with a reduced frequency or even an absence of passing your bowels. However, symptoms such as difficulty passing stools, hard stools and abdominal discomfort can also fall within the definition of constipation. There are published guidelines on the matter (a great review on the subject is titled American Gastroenterological Association Technical Review Of Constipation and is available on the associations website) which are worth reading if you are looking for in-depth information regarding classifications.