Anti-HIV drugs can also disrupt your metabolism – the way your body processes the things it needs to work properly.
Specifically, anti-HIV drugs can cause abnormal levels of blood lipids – cholesterol and triglycerides and also blood sugar.
There are two types of cholesterol: HDL cholesterol, often called 'good' cholesterol, and LDL, or 'bad' cholesterol.
Levels of HDL cholesterol are often reduced in people with HIV and other chronic illnesses. High levels of LDL cholesterol indicate that you are at greater risk of heart disease, and increases in LDL cholesterol are often seen in people taking anti-HIV drugs.
If you have high LDL cholesterol, the following factors increase your risk of heart disease even further:
- High blood pressure.
- A family history of heart disease.
- Being physically unfit.
- Being aged over 45 for men and over 55 for women.
- Insulin resistance or diabetes.
- High blood sugars.
- Being very overweight, particularly with a lot of fat around the middle.
- Use of stimulant recreational drugs like cocaine or amphetamines.
It is particularly important to monitor LDL cholesterol levels if you are taking a protease inhibitor.
Triglycerides are fatty acids derived from fat, sugar and starches in food. These travel through the bloodstream and are stored in tissues or in the liver. Levels of triglycerides can be increased by some anti-HIV drugs.
Glucose is a form of sugar found in the blood. High levels of glucose can increase the risk of heart disease. Levels of glucose can be increased by some anti-HIV drugs.
Insulin is the substance produced by the body to control glucose levels in the blood. Some people taking anti-HIV drugs need to produce more insulin to keep their blood levels of glucose normal. This is called insulin resistance. It may be necessary to have your insulin levels tested.
Symptoms of metabolic change
Abnormal levels of fats and sugars in the blood can sometimes cause symptoms including:
- Dizziness (due to high blood pressure).
- Loss of concentration.
- More frequent urination.
However, some people don’t notice any symptoms, even when they’ve had abnormal levels of fats and sugars for a long time and are at greater risk of heart disease.
Heart disease and anti-HIV drugs
Levels of fats in your blood may start to rise when you start HIV treatment, particularly if you are taking certain protease inhibitors. Sometimes they can increase so much that it’s necessary to change your diet, start exercising, or take a medication to control them.
Large studies of people taking protease inhibitors have shown that they have a slight, but nevertheless significant, increase in their risk of heart disease. Some (but not all) studies have also suggested that abacavir (Ziagen, also in the combination pills Kivexa and Trizivir) might increase the risk of heart disease, particularly for people who already have risk factors for heart problems.
If you have any existing risk factors for heart disease, your HIV treatment should be carefully chosen to ensure that it doesn’t raise the risk even further. And a 'risk' of heart disease does not automatically mean that heart problems will develop. A lot can be done to prevent this happening.
First of all, your cholesterol, triglyceride and glucose levels should be monitored at each routine clinic visit. This will mean that your doctor can spot any warning signs early.
Looking after your heart
There is also a lot you can do to help keep your blood lipids within safe limits. This includes eating a good diet with lots of fresh fruit and vegetables and without too much fat, regular exercise, and not smoking.
In some circumstances your doctor might prescribe what are called lipid-lowering drugs. These are used to treat heart disease and hardening of the arteries and include statins (to lower cholesterol) and fibrates (to lower triglycerides and also cholesterol). Some statins can interact with protease inhibitors, and both statins and triglycerides can cause their own side-effects, so your doctor will monitor you to see if these are developing.
Some drugs are also being investigated to see how effective they are at controlling glucose and insulin in HIV-positive people.