Medicines for diet problems
There are medicines that can help with weight loss, 
and digestion problems.
Appetite stimulants
Appetite stimulants are for people who have lost a lot of weight or have cachexia and have a loss of appetite. They work for some people.
Doctors can use the following hormone drugs:
- megesterol acetate (Megace)
- medroxyprogesterone acetate (Depo Provera and Provera)
Both drugs increase appetite and food intake. So, they can be helpful for people with cancer who have nutritional problems.
These drugs might also help you put on weight, but this can take up to 8 weeks.
Researchers did a of studies in 2018. The researchers found that megesterol acetate compared with a dummy drug (placebo) had moderate evidence for weight gain.
Most of the weight gain seems to be fat and fluid rather than muscle mass.
The side effects are usually very mild and you may not have any at all. But they can cause:
- nausea (feeling and being sick)
- headaches
- swelling from fluid retention
- tummy (abdominal) pain
- blood clots
- impotence in men
- difficulty sleeping (insomnia)
- feeling dizzy or shaky or nervous
- constipation
- hot flushes and sweats
- tiredness
- difficulty breathing
- a rounded face
- high blood pressure
- a rise in blood sugar levels
You need to check your blood sugar levels more when taking these drugs if you have diabetes. You might need to adjust the dose of your diabetes medicine.
You should not take these drugs if you are pregnant or thinking about getting pregnant.
Steroids
Doctors use steroids for many different illnesses and conditions. The body naturally makes them. They are also made artificially and used as medicines. They come as tablets, liquids or injections.
Steroids can help to control chemotherapy sickness in people with cancer. These are drugs like dexamethasone or methylprednisolone. They can also improve appetite and food intake.
These drugs can also increase your sense of well being. They sometimes cause extreme happiness (euphoria). This is a benefit if you are feeling very low, anxious or depressed about your cancer. But some people may experience these mood changes as very unsettling.
Doctors sometimes use steroids to help people gain weight. But there can be problems if you take them long term. Much of the weight you gain on steroids is due to fluid retention.
After taking them for a few weeks, they begin to interfere with the production of protein in your muscles. If used long term, they can cause muscle wasting. So, you need to use steroids under the supervision of your doctor.
Some side effects of steroids are:
- an increased risk of infection
- difficulty sleeping, particularly if you take them late in the day
- indigestion
- high blood sugar levels, especially if you have diabetes
- mood changes and suicidal thoughts in some people
- a burning or tingling sensation around your bottom during a steroid injection into a vein (intravenous)
Anti sickness drugs (anti emetics)
Feeling and being sick is best controlled with medicines. These drugs are called anti sickness drugs, anti nausea drugs or anti emetics.
There are many anti sickness drugs to choose from. Tell your doctor or pharmacist if one drug does not work for you. They can often suggest another you can try.
Let your doctor or pharmacist know as soon as possible if you get side effects from your anti sickness drug.
5HT3 receptor antagonists
5HT3 receptor antagonists include drugs such as:
- ondansetron (Zofran)
- granisetron (Kytril)
- tropisetron (Navoban)
- palonosetron
These drugs can cause:
- headaches
- constipation
- flushing of the skin
- a reaction at the drip site
NK1 receptor antagonists
NK1 receptor antagonists include drugs such as:
- aprepitant
- fosaprepitant
- rolapitant
These drugs can cause:
- a loss of appetite
- weakness
- constipation
- stomach discomfort
- headaches
- hiccups
NEPA
NEPA is a combination of netupitant and palonosetron.
These drugs can cause:
- weakness
- headaches
- constipation
Dopamine receptor antagonists
Dopamine receptor antagonists include drugs such as:
- metoclopramide (Maxalon)
- prochlorperazine (Stemetil)
- haloperidol
- olanzapine
Some side effects are:
- twitching of the arms, legs or face
- drowsiness
- a low blood pressure
Other drugs:
Other anti sickness drugs include cyclizine and lorazepam. They can cause drowsiness. Domperidone (Motilium) can make your mouth dry.
In some people, sickness from chemotherapy does not get better with anti sickness drugs. In these situations, doctors can use a drug called nabilone. Nabilone is a man made (synthetic) form of cannabis. You might have to stay in hospital to have nabilone.
Nabilone might cause drowsiness and dizziness.
Drugs for diarrhoea
The most commonly used drugs for diarrhoea are:
- codeine phosphate
- Ioperamide (Imodium)
All these drugs slow the movement of the bowel. Codeine phosphate is also a painkilling drug. But it is also used to treat severe diarrhoea because it causes constipation.
Side effects of anti diarrhoea drugs are not common, but they can happen. Tell your doctor if any of these symptoms are severe or do not go away. Some of these symptoms include:
- dizziness
- drowsiness
- feeling and being sick
- wind (flatulence)
- constipation
- confusion
- headaches
Drugs for constipation
These are called laxatives. There are different ones that work in different ways:
- bulk forming laxatives work by swelling up inside your bowel, softening and increasing the amount of stool, which encourages your bowels to open
- stimulant laxatives work by speeding up bowel movement
- osmotic laxatives work by drawing more water into your bowel, making your stools softer and easier to pass
Different laxatives have different side effects.
Bulk forming laxatives can cause wind and swelling in the stomach (abdomen). Very rarely they can block up your bowel. So, you should drink plenty of water with these drugs to help prevent it.
Other types of laxatives can cause stomach cramps and wind. Large doses can cause diarrhoea. The side effects usually go away once your bowels have opened. Contact your doctor if the cramping continues or if you have swelling of your stomach. Also, let them know if you develop diarrhoea.
Painkillers
Painkillers are also called analgesics or analgesia. Severe pain can make you lose your appetite and feel sick. If your pain is under control you are more likely to feel like eating.
