Do Benzodiazepines Cause Constipation, and What Helps During a Taper?

Key Takeaways

• Constipation is a known side effect of benzodiazepines and a listed symptom of withdrawal in the Ashton Manual, so it can appear on a steady dose or when the dose comes down.
• A taper can upset the gut through overactivity in the autonomic nervous system and through benzodiazepine receptors in the gut itself, with less movement, less food, and less fluid piling on top.
• Fiber added a little at a time, steady fluids, a daily walk, and regular meal and bathroom timing are the plain measures that help, the same ones that help constipation from any other cause.
• Over-the-counter laxatives fall into four classes that differ in speed and in how well they suit regular use, so the choice is one to make with the prescriber.
• Some patients in withdrawal are sensitive to magnesium, and trying it as a laxative or for any other reason is a decision for the patient and a physician who understands the pharmacology.
• Several days without a bowel movement, together with growing abdominal pain, vomiting, blood in the stool, or a fever, calls for a prompt visit to the doctor, and severe abdominal pain or heavy bleeding is a reason to call 911.
• Constipation is not a reason to speed up or stop the taper, because faster cuts tend to make withdrawal symptoms worse and stopping abruptly can bring severe reactions, including seizures.
• Professor Ashton writes that most digestive symptoms get better after withdrawal, though in a few people they persist.

Do benzos cause constipation, and can a taper bring it on?

Yes, on both counts. Constipation is a known side effect of benzodiazepines themselves, and it is a listed symptom of benzodiazepine withdrawal. So, it can be present on a steady dose, and it can appear or get worse when the dose comes down.

In the Ashton Manual, Professor C. Heather Ashton lists the gastrointestinal symptoms of withdrawal in Table 1 of Chapter III: nausea, vomiting, diarrhea, constipation, pain, distension, and difficulty swallowing. Yet, constipation is a symptom that patients tend to keep to themselves.

A patient who took a benzodiazepine as prescribed and now has a sluggish gut has done nothing wrong. Physical dependence is not addiction. It is the body’s adaptation to a medication taken every day, and the gut is one place where that adaptation is felt.

Why does a taper upset the gut?

Professor Ashton offers two possible explanations in Chapter III. The first is overactivity in the autonomic nervous system, which controls the movement and secretions of the gut and is, in her words, “very reactive to stress.” The second is the presence of benzodiazepine receptors in the gut itself, although she adds that it is not clear what they do.

The ordinary causes pile on top. A person in a hard stretch of a taper often moves less, eats less, and drinks less, and each of those slows the bowel. Anxiety does not help either.

So, the bowels can swing. Some patients are constipated one week and loose the next, with bloating and cramping in between, the picture patients call benzo belly. The Manual describes the same complaints as symptoms associated with irritable bowel syndrome, and it notes that hospital investigations usually find no abnormality.

What helps with constipation during a benzodiazepine taper?

The measures are plain, the same ones that help constipation from any other cause. The evidence that any of them changes withdrawal itself is limited, and how well each one works varies from person to person.

Fiber comes first. Fruit, vegetables, beans, and whole grains are best added a little at a time, because a sudden jump in fiber brings gas and bloating to a gut that is already irritable.

Professor Ashton advises a normal healthy diet without food fads, and she warns that overly restrictive diets can do harm. Nutrition during withdrawal has its own article.

Fiber needs fluid to do its work. How much? There is no magic number of cups. The Manual says that requirements vary with body size, temperature, and exercise, and that there is no need to drink extra amounts during withdrawal to flush anything out.

Movement helps too. The Manual recommends regular moderate exercise during withdrawal, and a daily walk counts. Regular timing matters as well, meaning meals at about the same hours and an unhurried visit to the bathroom after breakfast, when the bowel tends to be most active.

What about laxatives and magnesium?

Over-the-counter products fall into four main classes. Bulk-forming fiber supplements add volume to the stool, stool softeners add moisture, osmotic laxatives draw water into the bowel, and stimulant laxatives make the bowel contract. They differ in speed and in how well they suit regular use, so the choice is one to make with the prescriber, who knows the patient’s other medications.

Patients also ask about magnesium. Magnesium citrate is one form sold as a laxative, and it belongs to the osmotic class. Some patients in withdrawal find that they are sensitive to magnesium, and individual response varies.

Whether magnesium does anything for withdrawal itself is a separate question with limited evidence behind it. So, trying it, as a laxative or for any other reason, is a decision for the patient and a physician who understands the pharmacology. No laxative or supplement takes the place of a gradual taper.

When does constipation need a doctor?

While most constipation during a taper is uncomfortable and nothing more, being in withdrawal does not rule out an unrelated bowel problem. A few signs deserve a prompt visit to the patient’s own doctor.

Any one of them is enough: several days with no bowel movement together with growing abdominal pain, vomiting, blood in the stool, or a fever. A change in bowel habit that goes on for weeks deserves a visit as well.

Call 911 for severe abdominal pain, vomiting that will not stop, heavy bleeding, a seizure, or any other medical emergency.

Constipation is not a reason to speed up or stop the taper.

Unfortunately, days of bloating and straining wear a person down, and the tempting conclusion is that the answer is to get off of the medication faster. It is the wrong conclusion. Faster cuts tend to make withdrawal symptoms worse, the gut included, and stopping abruptly can bring severe withdrawal reactions, including seizures.

Gut symptoms are managed inside a slow taper. When they spike after a dose reduction, the patient may choose to hold the dose for a short stretch while things settle and to make the next step smaller, with the prescriber’s help, and a hold that does not settle within a few weeks goes back to the prescriber rather than on indefinitely.

Professor Ashton writes in Chapter II that the person tapering must be in control of the pace, and the Maudsley Deprescribing Guidelines describe reductions that get smaller as the dose gets lower. A taper built this way takes months, sometimes longer.

Fortunately, the gut usually settles with time.

Professor Ashton writes that most digestive symptoms get better after withdrawal. She adds that in a few people they persist.

Dr. Mark Leeds is an osteopathic physician and deprescribing specialist in Fort Lauderdale, Florida. In his practice, gut symptoms that flare after a dose reduction are information about the pace of the taper, never a failure by the patient. The patient decides when the next reduction happens.

Dr. Leeds’ practice is a concierge practice, not an insurance practice, and its primary service is medically supervised benzodiazepine and z-drug tapering for patients in Florida. Contact the office to discuss a slow, patient-directed taper.

This article is educational. It is not medical advice, and reading it does not create a doctor-patient relationship. Decisions about starting, continuing, or tapering any medication should be made with your own physician.