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Medication abuse in eating disorders

Whakamanioro rongoā ki ngā matenga kainga

People with eating disorders often try to get rid of food so they do not 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 get rid of food from their bodies. Some drugs can also suppress a person's appetite, so they do not feel very hungry.


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


Diuretics make you wee more. Most diuretics are 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 increased urination. It can also lead to gastrointestinal problems.

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


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

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

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


Laxatives are substances that get rid of the food in your bowel. They do this by increasing the volume of poo or speeding up the time it takes for food to pass through your gut. Some laxatives act by making your muscles work more. This moves food through your intestines more quickly. Others coat the poo with oil, soften it or increase the amount of water or fibre in the poo. This also makes it move more quickly.

Many people with eating disorders use laxatives. They do this 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 does not. This is because they only make you lose water and electrolytes, not calories. Laxatives also mainly affect your large intestine. But this is after your small intestine has already absorbed the calories from the food.

rapid heart rateRegularly using laxatives can lead to medical problems. These include recurrent diarrhoea, weakness, tummy pain, nausea and vomiting. They include dehydration and electrolyte imbalance (in particular, low levels of potassium). Also, finger clubbing, skin problems and heart problems. Many of these problems are caused by chronic dehydration.

Using laxatives regularly may also mean you need larger 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 affect the nerves that 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 and constipation. They include increased anxiety (feeling edgy, irritable, tense and angry). They also include urges or cravings to take laxatives. These side effects can be uncomfortable and distressing at first. But your body becomes used to not taking laxatives and the side effects start to go away within about two weeks.

Appetite suppressants (diet pills)

People with eating disorders often take appetite suppressants to dull their appetite. Appetite suppressants include diet pills and some other medicines. This is so they feel like eating less and lose weight.

These appetite suppressants may be prescription drugs, over-the-counter medicines or substances like caffeine. A quarter to half of people with eating disorders have used appetite suppressants. But there is very little evidence that they actually help you lose weight. Some appetite suppressants can cause serious medical problems. These can include increases in blood pressure, seizures and bleeding in the brain. They can also include cardiac irregularities, respiratory problems and psychosis. These effects may be greater if you take 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. Adapted by HealthInfo clinical advisers. Last reviewed March 2024.


Page reference: 76232

Review key: HIEDI-73561