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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 purging means vomiting, but there are other ways to purge as well. Many people with eating disorders use drugs to help with purging. This includes 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.

Purgatives

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

Diuretics

Diuretics make you urinate (wee) 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 develop a tolerance for it and need more of it to get the same effect. 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 build up and take a long time to clear from your body.This is especially true if you've been taking emetics regularly, since you can become tolerant and 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 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. 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 develop tolerance and need bigger amounts to get the same effect.

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.

You can also get side effects 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 like caffeine. A quarter to half of people with eating disorders have used appetite suppressants at some time, but there is very little evidence that they 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: Long-term effects of an eating disorder

Written by the South Island Eating Disorders Service, Canterbury DHB. Adapted by HealthInfo clinical advisers. Last reviewed January 2021.

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Page reference: 76232

Review key: HIEDI-73561