How to Evaluate, Prevent & Manage Constipation in Aging

Constipation is not a glamorous topic, but it’s certainly important, especially in older adults.

As anyone who has experienced occasional — or even chronic — constipation can tell you, it can really put a damper on quality of life and well-being.

Constipation can also cause more substantial problems, such as:

• Severe abdominal pain, which can lead to emergency room visits
• Hemorrhoids, which can bleed or be painful
• Increased irritability, agitation, or even aggression, in people with Alzheimer’s disease or other forms of dementia
• Stress and/or pain that can contribute to delirium (a state of new or worse confusion that often happens when older adults are hospitalized)
• Fecal incontinence, which can be caused or worsened by having a hard lump of stool lodged in the lower bowel
• Avoidance of needed pain medication, due to fear of constipation

Fortunately, it’s usually possible to help older adults effectively manage and prevent constipation. This helps maintain well-being and quality of life, and can also improve difficult behaviors related to dementia.

The trouble is that constipation is often either overlooked or sub-optimally managed by busy healthcare providers who aren’t trained in geriatrics. They are often focused on more “serious” health issues. Also, since many laxatives are available over-the-counter (OTC), some providers may assume that people will treat themselves if necessary.

Personally, I don’t like this hands-off approach to constipation. Although several useful laxatives, such as polyethylene glycol (brand name Miralax)  are indeed available OTC, I’ve found that the average person doesn’t know enough to correctly choose among them.

Also, although in geriatrics we often do end up recommending or prescribing laxatives, it’s vital to start by figuring out what is likely to be causing — or worsening — an older person’s constipation.

For instance, many medications can make constipation worse, so we usually make an attempt to identify and perhaps deprescribe those.

In short, if you’re an older adult, or if you’re helping an older loved one with health issues, it’s worthwhile to learn the basics of how constipation should be evaluated and managed. This way, you’ll be better equipped to get help from your health providers, and if it seems advisable, choose among OTC laxative options.

Here’s what I’ll cover in this article:

• Common signs and symptoms of constipation
• Common causes of constipation in older adults
• Medications that can cause or worsen constipation
• How constipation should be evaluated, and treated
• The laxative myth you shouldn’t believe
• 3 types of over-the-counter laxative that work (and one type that doesn’t)
• My approach to constipation in my older patients

I’ll end with a summary of key take-home points, to summarize what you should know if you’re concerned about constipation for yourself or another older person.

Common signs and symptoms

Constipation can generally be diagnosed when people experience two or more of the following signs, related to at least 25% of their bowel movements:

• straining
• hard or lumpy stools
• a sense of incomplete evacuation
• the need for “manual maneuvers” (some people find they need to help their stools come out)
• fewer than 3 bowel movements per week

People often want to know what is considered “normal” or “ideal,” when it comes to bowel movements. Although it’s probably ideal to have a bowel movement every day, it’s generally considered acceptable to have them every 2-3 days, provided they aren’t hard, painful, or difficult to pass.

The handy Bristol Stool Scale can be used to describe the consistency of a bowel movement, with Type 4 stool often being considered the “ideal” (formed but soft).

Constipation is pretty common in the general population and becomes even more so as people get older.  Experts estimate that over 65% of people over age 65 experience constipation, with straining being an especially common symptom.

Other symptoms that may be caused by constipation in older adults

Constipation may be associated with a feeling of fullness, bloating, or even pain in the belly. In some people, this may interfere with appetite.

Although most older adults will admit to symptoms of constipation when asked, a person with Alzheimer’s or a related dementia may be unable to remember or relay these symptoms. Instead, they might just act out or become more irritable when they are constipated.

Prolonged constipation can also lead to a more urgent problem called “fecal impaction.” This means having a hard mass of stool stuck in the rectum or colon. It happens because the longer stool remains in the colon, the dryer it tends to get (which makes it harder to pass).

Impaction tends to be very uncomfortable, and can even provoke a full-on crisis of belly pain. It can also be associated with diarrhea and fecal incontinence.

Clearing out impacted stool can be hard to do with oral laxatives; these can even make things worse by creating more pressure and movement upstream from the blockage.

Fecal impactions are usually dislodged using treatments “from below” to soften and break up the lump, such as suppositories and/or enemas. (I address what type of enema is safest below.) They sometimes require help from clinicians in urgent care or even the emergency room.

Common causes of constipation in older adults

Like many problems that affect older adults, constipation is often “multifactorial,” or due to multiple causes and risk factors.

To have a normal bowel movement, the body needs to do the following:

• Move fecal material through the colon without excess delay (stool gets dryer and harder, the longer it stays in the colon).
• Coordinate a defecation response when stool moves down to the rectum, which requires properly working nerves and pelvic muscles.

As people get older, it becomes increasingly common to develop difficulties with one or both of these physical processes. Such problems can be caused or worsened by:

• Medication side-effects (more on those below)
• Insufficient dietary fiber
• Insufficient water intake
• Electrolyte imbalances, including abnormal levels of blood calcium, potassium, or magnesium
• Endocrine disorders, including hypothyroidism
• Slow transit due to chronic nerve dysfunction, which can be due to neurological conditions (including Parkinson’s disease) or can be caused by long-standing conditions that eventually damage nerves, such as diabetes
• Irritable bowel syndrome
• Pelvic floor dysfunction
• Psychological factors, such as anxiety, depression, or even fear of pain during the bowel movement
• Very low levels of physical activity
• “Mechanical obstruction,” which means that the colon or rectum — or their proper function — is impaired by some kind of mass, lump, narrowing, or another physical factor
  • A tumor can cause this problem, but there are also non-cancerous reasons that a person can develop a mechanical obstruction affecting the bowels.

Medications associated with constipation

Several commonly used medications can cause or worsen constipation in older adults. They include:

• Anticholinergics, a broad class which includes sedating antihistamines, medications for overactive bladder, muscle relaxants, anti-nausea medications, and more. (This group of medications is also associated with worse brain function; they block acetylcholine, which is used by brain cells and by the nerves in the gut.)
• Opiate painkillers, such as codeine, morphine, oxycodone
• Diuretics
• Some forms of calcium supplementation
• Some forms of iron supplementation (often prescribed for anemia)

It’s not always possible or desirable to stop every medication associated with constipation. If a medication is otherwise providing an important health benefit and there’s no less constipating alternative, we can continue the medication and look for other ways to improve bowel function.

Still, it’s important to consider whether any current medications can be deprescribed, before deciding to use laxatives and other management approaches.

If opioids are absolutely necessary to manage pain (such as in someone with cancer, for instance), a special type of medication can be used, to counter the constipating effect of opioids in the bowel. This is generally better than depriving a person of much-needed pain medication.

How to evaluate constipation

How to treat constipation basically depends on what appears to be the main causes and contributors to a person’s symptoms.

An evaluation should start with the health provider asking for more information regarding the symptoms, including how long they’ve been going on, as well as the frequency and consistency of stools.

It’s also important for the clinician to ask about “red flags” that might indicate something more serious, such as colon cancer. These include:

• Blood in the stool (which can be red, or black and “tarry” in appearance)
• Weight loss
• New or rapidly worsening symptoms

The next steps of the evaluation will depend on a person’s medical history and symptoms. It’s generally reasonable for a healthcare provider to check for these common causes of constipation:

• Medication side-effects
• Low intake of dietary fiber
• Low fluid intake
• Common causes of painful defecation, such as hemorrhoids or anal fissures

Evaluation for possible mechanical obstruction will depend on what the clinician sees on physical examination, the presence of potential red flags, and other factors. Generally, a rectal exam is a good idea.

In a 2013 review, the American Society for Gastroenterology recommends that clinicians evaluate for possible pelvic floor dysfunction mainly in those people whose constipation doesn’t improve with lifestyle changes and over-the-counter (OTC) laxatives.

They also recommend diagnostic colonoscopy only for people with alarm symptoms, or who are overdue for colorectal cancer screening.

How to treat constipation

In most older adults with constipation, there are no red flags or signs of mechanical obstruction.

To treat these cases of “garden-variety” constipation, geriatricians usually use a step-wise approach:

• Identify and reduce constipating medications if possible.
  • This might mean checking to see if iron is really indicated for anemia treatment (it might no longer be needed)
• Increase dietary fiber intake and fluid intake, if indicated.
  • Prunes are often effective because they contain fiber and also sorbitol, a non-absorbable type of sugar that draws water into the bowel. A randomized study published in 2011 found that prunes were more effective than psyllium (brand name Metamucil), for the treatment of constipation.
  • Other forms of fiber should be slowly increased, to avoid bloating or discomfort. Adequate hydration is essential, because otherwise, fiber can become a hard mass in the colon that is difficult to move out.
  • For a detailed technical take on the effect of fiber in the bowel, see Understanding the Physics of Functional Fibers in the Gastrointestinal Tract: An Evidence-Based Approach to Resolving Enduring Misconceptions about Insoluble and Soluble Fiber.
• Encourage a regular toilet routine, with time on the toilet after meals and/or physical activity.
• If necessary — which it often is — use over-the-counter laxatives to establish and maintain regular bowel movements.

The American Society of Gastroenterology recommends more in-depth constipation evaluation for older adults who fail to improve from this type of first-round treatment. Some older adults do have pelvic floor disorders, which can be effectively treated through biofeedback.

The laxative myth you shouldn’t believe

People often have concerns about using laxatives more than occasionally, because they’ve heard this can be dangerous, or risky.

This is a myth that really should be dispelled. Although medical experts used to worry that chronic use of laxatives would result in a “lazy” bowel, there is no scientific evidence to support this concern.

In fact, in their technical review covering constipation, the American Society of Gastroenterology notes that “Contrary to earlier studies, stimulant laxatives (senna, bisacodyl) do not appear to damage the enteric nervous system.”

(FYI: the “enteric nervous system” means the system of nerves controlling the digestive tract.)

Lifestyle changes and over-the-counter oral laxatives are the approaches endorsed as the first-line of constipation therapy, by the American Gastroenterology Society and others. There are no evidence-based guidelines that caution clinicians to only use laxatives for a limited time period.

The four types of OTC laxatives that I’ll cover in the next section have been used by clinicians and older adults for decades, and when used correctly, are considered safe and do not seem to cause any long-term problems.

That’s not to say that they should be used willy-nilly, or in any which way. You absolutely should understand the basics of how each type works, so let’s cover that now.

Three types of laxative that work (and one that doesn’t)

There are basically four categories of oral over-the-counter (OTC) laxative available. Three of them are proven to work. A fourth type is commonly used but actually does not appear to be very effective. Each has a different main mechanism of action.

The three types of OTC laxative that work are:

• Osmotic agents: These include polyethylene glycol (brand name Miralax), sorbitol, and lactulose. Magnesium-based laxatives also mostly work through this mechanism.
  • These work by drawing extra water into the stool, which keeps it softer and easier to move through the bowel.
  • Studies have shown osmotic agents to be effective, even for 6-24 months. Research suggests that polyethylene glycol tends to be better tolerated than the other agents.
  • Magnesium-based agents should be used with caution in older adults, mainly because it’s possible to build up risky levels of magnesium if one has decreased kidney function, and mild-to-moderately decreased kidney function is quite common in older adults.
• Stimulant agents: These include senna (brand name Senakot) and bisacodyl (brand name Dulcolax).
  • These work by stimulating the colon to squeeze and move things along more quickly.
  • Studies have shown stimulant laxatives to be effective. They can be used as “rescue agents” (e.g. to prompt a bowel movement if there has been none for two days) or daily, if needed.
  • Bisacodyl is also available in suppository form, and can be used this way as a “rescue agent.”
• Bulking agents: These include soluble fiber supplements such as psyllium (brand name Metamucil) and methylcellulose (brand name Citrucel).
  • These work by making the stool bigger. Provided the stool doesn’t get too dried out and stiff, a bulkier stool is easier for the colon to move along.
  • Bulking agents have been shown to improve constipation symptoms, but they must be taken with lots of water. Older adults who take bulking agents without enough hydration — or who otherwise have very slow bowels — can become impacted by the extra fiber.
  • People with drug-induced constipation or slow transit are not likely to benefit from bulking agents.

(For more details regarding the scientific evidence on these laxatives, see this 2013 technical review.)

And now, let’s address the type of OTC laxative that is least likely to work.

The type of OTC laxative that isn’t really effective is a “stool softener”, such as docusate sodium (brand name Colace).

These create some extra lubrication and slipperiness around the stool. They actually have often been prescribed by doctors; when I was a medical student, almost all of our hospitalized patients were put on some Colace.

But, the scientific evidence just isn’t there! Because this type of laxative is so commonly prescribed, despite a weak evidence base, the Canadian Agency for Drugs and Technologies in Health completed a comprehensive review in 2014. Their conclusion was:

“Docusate appears to be no more effective than placebo for increasing stool frequency or softening stool consistency.”

So, save your money and your time. Don’t bother buying docusate or taking it. And if a clinician suggests it or prescribes it, politely speak up and say you’ve heard that the scientific evidence indicates this type of laxative is less effective than other types.

Laxatives do work and are often appropriate to use, but you need to use one of the ones that has been shown to work.

About prescription laxatives

Newer prescription laxatives are also available, and may be an option for those who remain constipated despite implementing lifestyle changes and correctly used over-the-counter laxatives. These include lubiprostone (brand name Amitiza) and linaclotide (brand name Linzess).

But, it’s not clear, from the scientific research, that they are more effective than older over-the-counter laxatives. In its technical review, the American Society of Gastroenterology noted that “meta-analyses, systematic reviews, and the only head-to-head comparative study suggested that some traditional approaches are as effective as newer agents for treating patients with chronic constipation.”

Since these newer medications have a more limited safety record and are also expensive, they probably should only be used after an older person has undergone careful evaluation, including evaluation for possible pelvic floor disorders.

About enemas

Enemas are another form of “constipation treatment” available over-the-counter in the U.S.

The main thing to know is that the most commonly available form, saline enemas (Fleet is a common brand name), have been associated with serious electrolyte disturbances and even kidney damage. Because of this, the FDA issued a warning in 2014, urging caution when saline enemas are used in older adults.

Enemas certainly can be helpful as “rescue therapy,” to prevent a painful fecal impaction if an older person hasn’t had a bowel movement for a few days. But they should not be used every day.

Frequent use of enemas is really a sign that a person needs a better bowel maintenance regimen. This often means some form of regular laxative use, plus a plan to use a little extra oral laxative as needed, before things reach the point of requiring an enema.

If an enema appears necessary, experts recommend that older adults avoid saline enemas, and instead use a warm tap water enema, or a mineral oil enema.

My approach to constipation in my older patients

Generally, to help my older patients with garden-variety constipation, I start by checking for medications that are constipating, and then recommending prunes and encouraging more fiber-rich foods. As noted above, a randomized trial found that 50 grams of prunes twice daily (about 12 prunes) was more effective in treating constipation than psyllium (brand name Metamucil).

Then we usually add a daily osmotic laxative, such as polyethylene glycol (Miralax). If needed, we might then add a stimulant agent, such as senna.

We do sometimes try a bulking agent, but I find that many frailer older adults tend to get stoppered up by the extra bulk. Again, if you use a supplement (such as Metamucil) to put extra fiber in the colon but can’t keep things moving along fast enough, that extra fiber might dry out and become very difficult to pass as a bowel movement.

It usually takes a little trial and error to figure out the right approach for each person, so it’s essential for an older person — or their family — to keep a log of the bowel movements and the laxatives that are taken. If a person has loose stools or too many bowel movements, in response to a given laxative regimen, we dial back the laxatives a bit.

It’s also important to have a plan for “rescue,” which means adding some extra “as-needed” laxative (usually either senna or a suppository), if a person hasn’t had a bowel movement for 2-3 days. The goal of rescue is to avoid the beginnings of fecal impaction.

Last but not least, we also try to make sure an older person is getting enough physical activity, and to establish a routine of having the person sit on the toilet after meals.

With a little time and effort, we usually find a way to help an older person have a comfortable bowel movement every 1-2 days.  This does often require taking a daily oral laxative indefinitely, but this is quite common in geriatrics. And as best we can tell, daily laxatives are unlikely to cause harm, provided one doesn’t use a magnesium laxative daily.

The most important take-home points on constipation in older adults

Here’s what I hope you’ll take away from this article:

1.Know that constipation is common but shouldn’t be considered a “normal” part of aging. It deserves to be evaluated and managed by your healthcare providers.

• Be sure to ask for help, if you’ve noticed any difficulties having a comfortable bowel movement every 1-2 days.
• A log of bowel movements and related symptoms will be very helpful to your health providers.

2. If an older person with Alzheimer’s or another dementia is acting out, consider the possibility of constipation.

3. Be sure to speak up if you’ve noticed any “alarm symptoms.”

• The main ones to look for are red blood in the stool, black or tarry stools, unintended weight loss, and new or worsening symptoms.

4. An initial evaluation of constipation should include the following:

• A review of concerning symptoms
• A review of diet, fiber, and fluid intake
• Checking for medications that cause or aggravate constipation (especially anticholinergics) and making sure that any prescribed iron is really necessary
• A rectal exam

5. Most garden-variety constipation can be effectively managed through a combination of lifestyle changes, deprescribing constipating medications, and using over-the-counter (OTC) laxatives.

• Lifestyle changes to consider include avoiding mild dehydration, eating fiber-rich foods, getting enough physical activity, and encouraging a regular toilet routine (e.g. sitting on the toilet after meals).
• Anticholinergics and other constipating medications should be deprescribed whenever possible.
• Daily prunes are especially effective as a “natural” laxative, since they contain soluble fiber and exert an “osmotic laxative” effect.

6. It is often ok to use OTC oral laxatives daily or regularly.

• Many older adults will need to use OTC laxatives to maintain regular bowel movements.
• There is no credible evidence that it’s harmful to use OTC oral laxatives long-term.

7. Three types of OTC laxative have proven efficacy: bulk-forming fiber supplements, osmotic laxatives, and stimulant laxatives. It often takes some trial and error to find the right regimen for a person.

• Osmotic laxatives such as polyethylene glycol (brand name Miralax) are well-tolerated by most older adults, and can be used daily.
• Fiber supplements such as psyllium (brand name Metamucil) are usually effective, provided an older adult drinks enough fluid and doesn’t suffer from a condition causing slow colonic transit. Fiber supplements that get dried out in a slow colon can worsen blockage.
• Stimulant laxatives such as senna are often helpful, and can be used in combination with an osmotic laxative. They can be used daily or as needed, for “rescue therapy.”

8. “Stool softeners” such as docusate sodium (brand name Colace) do not appear to be effective. Don’t bother taking them.

9. It’s best to have a bowel maintenance plan and also a “rescue plan.”

• Your health providers can help you determine which additional laxatives to use “as-needed,” if a person hasn’t had a bowel movement for a few days.
• Frequent use of “rescue” laxatives usually means the regular regimen should be adjusted.

10. Be prepared to do some trial and error, to figure out the best way to manage chronic constipation in any particular person.

• Be sure to keep track of bowel movements and what laxatives you — or your older relative — are taking.
• Your clinicians will need this information in order to advise you on how to further adjust your laxative use.

I hope you now feel better equipped to address this important issue for yourself, or on behalf of an older loved one. 

This article was first written in 2018. Minor updates were made in July 2024 (the basics of constipation management don’t change quickly!).