Open a PDF version to print this topic

HealthInfo Canterbury

Medication abuse in eating disorders

People with eating disorders often try to get rid of food so they don't gain weight. This is called purging.

We often think of vomiting as purging, but there are other ways to purge as well, including using drugs to help get rid of food from your body. Some drugs can also suppress a person's appetite, so they don't feel very hungry. Many people with eating disorders use drugs to help with purging.

Purgatives

Purgatives are drugs or other substances that make you vomit (emetics), or urinate (diuretics), or cause diarrhoea (laxatives).

Diuretics

Diuretics make you urinate, or pee, more. Most diuretics are tablets, either prescribed by a doctor, or available over the counter. Some other substances, such as caffeine, also act like diuretics.

Diuretics have no effect on calories or body fat. They just make you lose water, which changes the balance of electrolytes in your body. This can lead to serious medical problems, including heart problems. Too much caffeine can lead to restlessness, insomnia, irritability, nervousness, and gastrointestinal problems, as well as increased urination.

If you use a diuretic regularly, you may need more of it to get the same effect – you develop a tolerance for it. And you may have problems with long-term water retention when you stop taking diuretics.

Emetics

Emetics are substances that make you vomit. Around 30% of people with eating disorders have used emetics at some time, to make vomiting easier.

Some emetics take a long time to clear from your body, so they build up.This is especially true if you've been taking emetics regularly, since you can become tolerant (you need more of the drug to make you vomit). This is extremely dangerous, as these drugs are highly toxic above certain doses.

As well as nausea and vomiting, emetics can cause gastrointestinal problems, muscle weakness, shortness of breath and heart problems.

Laxatives

Laxatives are substances that get rid of the food in your bowel by increasing the volume of stools (poos), or speeding up the time it takes for food to pass through your gut. Some laxatives act by making your muscles work more, which moves food through your intestines more quickly. Others coat the stool with oil, or soften it, or increase the amount of water or fibre in the stool so that it moves more quickly.

Many people with eating disorders (between 38% and 75%) use laxatives to try to counteract the effects of bingeing and to lose weight. They believe this will get rid of the food they eat, but it doesn't. One study found that even though laxatives cause a large amount of diarrhoea, they decrease the number of calories digested by just 10%. This is because they only make you lose water and electrolytes, not calories. They also mainly affect your large intestine, after your small intestine has already absorbed the calories from the food.

rapid heart rateRegularly using laxatives can lead to medical problems including recurrent diarrhoea, weakness, tummy pain, nausea, vomiting, dehydration, electrolyte imbalance (in particular, low levels of potassium), finger clubbing, skin problems, and heart problems. Many of these problems are caused by chronic dehydration because you're losing too much water.

Using laxatives regularly may also mean you need greater amounts to get the same effect (you develop tolerance).

Sometimes people who abuse laxatives for too long can no longer do poos without them. This is because laxatives also affect the nerves that normally make the muscles of your bowel contract. These people need specialised retraining to help their muscles function again.

There are also side effects that happen when you try to stop using laxatives. These include water retention, constipation, increased anxiety (feeling edgy, irritable, tense, angry), and urges, or cravings, to take laxatives. Although these side effects can be uncomfortable and distressing at first, within a short time (usually about two weeks), your body becomes used to not taking laxatives and the side effects will start to go away.

Appetite suppressants (diet pills)

People with eating disorders often take appetite suppressants (including diet pills, and some other medicines) to dull their appetite, so they feel like eating less and lose weight.

These appetite suppressants may be prescription drugs, over-the-counter pills or medicines, or common substances such as caffeine. A quarter to half of people with eating disorders have used appetite suppressants at some time, but there is very little evidence that appetite suppressants actually help you lose weight. Some appetite suppressants can cause serious medical problems, including increases in blood pressure, seizures, bleeding in the brain, cardiac irregularities, respiratory problems, and psychosis. These effects may be greater if you take some appetite suppressants with other substances, including caffeine.

On the next page: What are the long-term effects of an eating disorder?

Written by the South Island Eating Disorders Service, Canterbury DHB. Adapted by HealthInfo clinical advisers. Last reviewed December 2017.

Sources

Page reference: 76232

Review key: HIEDI-73561