Enema for Constipation
Which Ones Work Best

By Dr. Shrey Lakhotia, BDS

Enema for constipation

This constipation remedy is a solution injected through the anus into the rectum and sigmoid colon. 

Its purpose is to remove stool and gas via the anal opening. Enemas are much faster and more effective than laxatives for constipation relief.

Mechanism of action

Enema solutions usually contain water and an osmotic agent used to draw water into the colon. Enemas increase the volume of material in the colon. 

This quickly expands the lower intestinal tract, resulting in feelings of extreme bloating, cramping, peristalsis and an extreme urge for complete evacuation of the lower intestinal tract.

Enema for Constipation - Types of Enemas

Cleansing enemas

This is used to help prevent the escape of feces during surgery. It also prepares the intestine for certain diagnostic tests, like x-rays or colonoscopy. It is also helpful in relieving constipation or fecal impaction.

Here are the 4 types of cleansing enemas:

  • Large volume cleansing enema

  • Small volume cleansing enema

  • Cleansing enema (high): this is administered to cleanse as much of the colon as possible

  • Cleansing enema (low): this is administered to cleanse the rectum and sigmoid colon

Carminative enemas

This enema solution releases gas that distends the rectum and colon. For an adult, only 60 to 80 mL is required.

Retention enemas

tap water - enema and constipation

This introduces oil or medication into the rectum. There are 3 types:

•    Antibiotic
•    Anthelmintic
•    Nutritive

Antibiotic enema solutions are used to treat localised bacterial infections. Neomycin antibiotic is used to reduce bacteria in the colon before bowel surgery.

Return flow enemas

This is usually used for the expulsion of stool; 100 to 200 ML of fluid is flushed in and out of the rectum and sigmoid colon numerous times to stimulate peristalsis. 

This is repeated five or six times until stool and gas is expelled and abdominal distension is relieved.

Non-retention enemas

Hypertonic: 90 to 120 mL of solution (e.g. sodium phosphate).

  • Example:  Fleet's Phosphosoda Enema
  • Action:  Draws water into the colon
  • Strengths:  Effective in 5 to 10 minute
  • Adverse effects: Retention of sodium

Using Various Types of Enemas

Hypotonic:  Uses tap water

Strengths: It Distends the colon, stimulates peristalsis, and softens feces. It acts in 15 to 20 minutes.

Limitations: It can result in fluid and electrolyte imbalance and water intoxication.

Isotonic:  500 to 1,000 mL of normal saline

Strengths: It distends the colon, stimulates peristalsis and also softens feces. It starts acting in 15 to 20 minute.

Limitations: There is a possibility of sodium retention.

Soapsuds:  3-5 mL soap to 1,000 mL water

Strengths: Distends the colon. Effective in 10 to 15 minutes.

Limitations: It Irritates and can damage the mucosa lining of the colon.

Mineral Oil:  90 to 120 mL

Strengths: It lubricates the feces and mucosa. It starts acting in ½ to 3 hours.

Adverse effects: Rectal seepage, anal irritation, burning or itching of skin around the anus, impairment of the reflex of the rectum to expel stool when present, and finally, it may result in the infection or impaired healing of lesions around the anus and rectum.

A steroid enema solution

This is used to alleviate bowel inflammation in patients suffering from ulcerative colitis.

Medicated hypertonic enema solutions

These are used to remove excessive potassium or ammonia from the bloodstream via the rectal wall.  e.g.: Kayexalate is used to treat patients with very high serum potassium levels.

Which Should I Choose?

An Enema, or Magnesium

Orally administered magnesium is often prescribed by doctors for constipation. 

It acts as an osmotic laxative and is safer and much more comfortable than taking an enema. A magnesium based laxative like Milk of Magnesia or Epson Salt can be used to clear the bowel quickly.

Magnesium laxatives are not recommended for extended use. However, when a magnesium supplement is taken every day, it can be quite effective to keep the bowel clean and functioning normally. Taking a magnesium supplement may be the best way to avoid the dangers and discomforts of enemas.

Since the majority of Americans don’t get enough magnesium in their diet, a magnesium supplement may also result in numerous health benefits.

Note: As with any over-the-counter remedy, talk with your doctor before starting on a magnesium supplement. Supplemental magnesium may interfere with certain prescription medications. 

Those with kidney disease should not take a magnesium supplement unless instructed to do so by their doctor.

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

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