Medications for Constipation

Pharmacist Anusuya Kashi

By Pharmacist Anusuya Kashi

When are medications for constipation needed?

The following people are likely to suffer from chronic constipation. Those who:

  • Don’t get sufficient fiber in their diet
  • Eat a lot of junk food
  • Take prescription medications
  • Have low fluid intake

Diet and lifestyle changes are an important step in tackling chronic constipation.

However, if you suffer from an acute episode of constipation, you may need a constipation medication for short-term relief. 


Medications for Constipation

Milk of Magnesia

This is an osmotic laxative that works by drawing water into the colon. This product helps:

  • Hydrate the stool
  • Soften the stool
  • Promote easier evacuation of stool

Make sure to shake the bottle before measuring out a dose. Drink at least 8 ounces of water with every dose.

Due to its high level of magnesium, Milk of Magnesia is not recommended for regular use.

A Magnesium Supplement

If a person is looking for ongoing constipation relief, a magnesium supplement is recommended.

As a supplement, these may be used daily.

A magnesium supplement helps to supply the daily requirement of magnesium, thus helping to meet a nutritional need.

When purchasing a magnesium supplement, find one that also contains needed trace minerals.


Citrucel contains Psyllium, a natural fiber that helps bulk up the stool.

Second, psyllium absorbs water, helping to soften the stool.

If you are using Citrucel, make sure to take it with at least 8 ounces of water to avoid choking.

Some people experience side effects such as bloating and stomach cramping. If Citrucel is not taken with sufficient water, it may cause constipation to worsen.


Colace contains a stool softener called docusate.

It is often recommended for patients who need to avoid straining after surgery.

Docusate causes the stool to absorb water, which helps to soften stool and ease evacuation.

I recommend taking this product with about 8 ounces of water at bedtime.

If diarrhea develops or other side effects are noted, such as an irritation in the throat or cramping in the stomach, stop taking Colace and see your doctor.


Dulcolax is a rectal stimulant. It causes rectal muscles to contract forcing the elimination of formed stool.

It is available as an oral tablet and as a suppository.

Take the tablet at night to produce a bowel movement in the morning.

For faster results, use the suppository, which may produce a bowel movement within 15 minutes to an hour after insertion.

While Dulcolax is an effective laxative, it may cause cramping, irritation and general discomfort in the stomach. 


Senokot contains senna in combination with docusate sodium.

Senna acts to stimulate the intestinal muscles, and docusate is a stool softener.

Senokot may cause some discomfort, such as belching, nausea and cramping.

I recommend this product only in rare cases, such as:

  • When stool is hard or impacted
  • When it is important for a person to avoid straining

Senokot is recommended for those with heart disease, anal fissures, or women who have just given birth.

Other-the-counter conclusion

Reaching out for an over-the-counter medicine to deal with constipation may seem like the easiest solution.

However, if the problem persists for longer than a week or two, I recommend that you see your doctor, rather than continue to self-medicate.

Some over the counter laxatives can lead to an electrolyte imbalance, which can be dangerous for heart and nerve function. 

Prescription Medications for Constipation

Depending on the cause and severity of constipation, a doctor may prescribe one of the following medications for constipation.

Be careful to follow your doctor’s instructions regarding dosage and duration of treatment.


This product contains linaclotide, and it causes more frequent bowel movements.

Some people may develop diarrhea as a side effect.

Linzess works best when taken once a day on an empty stomach about half an hour before the first meal of the day.

Linzess is not intended for use by those 18 years of age or younger.


When the cause of constipation is unknown, Amitiza is probably the first drug your doctor will prescribe.

Amitiza contains lubiprostone, which helps stool to absorb water. This softens the stool, resulting in easier elimination.

Amitiza needs to be taken with food, and not more than twice a day.

Side effects may include headache, nausea, vomiting and diarrhea. 


Glycolax contains polyethylene glycol, which causes water to be drawn into the intestines. This helps to hydrate and soften the stool.

Many doctors will prescribe Glycolax if the patient has chronic constipation but is sensitive to dietary fiber supplements.


Duphalac, Cephula, Constulose and Enulose are all different brands of a prescription laxative called Lactulose.

Lactulose acts as an osmotic agent, pulling water into the colon, but it also has another effect.

Because it is not absorbed or degraded in the small intestine, it passes intact to the colon, where it ferments and stimulates peristalsis.

Unfortunately, methane gas is produced during this fermentation, which can lead to the common side effect of flatulence (passing of gas through the anus).

Consider other options first

  1. Even though numerous over-the-counter and prescription medications are available for treating constipation, most have undesirable side effects.

  2. If a person is on other medications, laxative medications for constipation may interfere with their absorption or efficacy. 

    Here are some medications that constipation drugs may interfere with:

              • Medications for heart or bone problems

              • Antibiotics

              • Blood thinners

Natural constipation relief may be better

 recommend that people first try to deal with constipation by using natural methods.

Start with:

  • Eating a fiber-rich diet
  • Drinking plenty of water
  • Getting regular exercise

When diet and exercise aren't enough 

When constipation persists, I recommend taking a magnesium product for constipation relief. 

Magnesium works in a number of ways:

  • It increases bulk of the stool, which in turn stimulates peristalsis
  • It softens stool by increasing its water content
  • It lubricates stool by keeping it moist
  • It has no harmful side effects

In my professional opinion, magnesium may be the best answer for constipation for those with healthy kidneys, once diet and exercise fail.

Medications for constipation should only be used for occasional, temporary relief. 

(Return from Medications for Constipation to What to Take for Constipation)

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