Drug interactions may occur between hepatitis C and HIV/AIDS treatment drugs and illicit drugs such as methamphetamines and interactions between other licit and illicit drugs.

Warning: Use this info as a guide only. Drug interactions will vary from person to person depending on things like the health of the individual (weight, diet, exercise, etc.), their metabolism (how food is broken down and converted to energy after eating), and the amount of drug used (how much and how often).

Drug interactions

Drug interactions affect many people at some time in their drug-using lives. A drug interaction is when 2 or more drugs are taken at the same time and produce a reaction that's different from the effect produced when the drugs are taken separately.

Interactions can be caused by many substances; some aren't drugs but they contain chemicals that can cause problems in certain combinations. These include herbs (such as St John's Wart), garlic, supplements (such as vitamin C) and some foods.

Drugs taken together do not always affect each other. But many do -sometimes in unexpected, dangerous and lethal ways. A drug interaction can cause:

• 1 drug to have a more powerful or less powerful effect than usual or,
• An effect that is totally different from that normally produced by each drug if taken separately.

A number of substances can be involved in drug interactions:

• Legally prescribed drugs - HIV/AIDS and Hep C antiviral treatments, anti-depressants and methadone, etc.
• Illicit drugs - heroin, ecstasy, speed and cocaine, etc.
• Over-the-counter preparations - paracetamol (like Panadol), cold and flu medicines, Aspirin, cough mixture and vitamins, etc.
• Substances used for complementary therapies - herbs and supplements, etc.
• Other substances - alcohol, tobacco and food, etc.

It's possible that long-term use of some illicit drugs - heroin, cocaine, speed and ecstasy - might harm your immune system. This is important to Hep C and HIV/AIDS positive drug users as many HIV/AIDS antivirals can also cause liver function problems and having Hep C can mean your liver is functioning poorly already.

The best way of limiting the possibility of an interaction involved in illicit drugs is to stop using. But many people find this too difficult or may not want to stop. If you do choose to use while you are taking medications, the best advice in the absence of research, is to stick to these precautions:

• Reduce the amount of any illicit drug that you take. This means taking only 1/3 or less of the amount you usually take,
• If possible, talk to your doctor about your plans to use drugs. Be aware though, this could lead to discrimination: for example, some states have compiled lists of the names of so-called drug addicts.
• Be especially careful if you are taking HIV/AIDS antivirals such as protease inhibitors. These antivirals are renowned for being involved in some serious interactions with other drugs including illicit drugs such as ecstasy. You may want to contact your local AIDS Council for more information.
• You might want to discuss changing your antiviral combination with your doctor. Protease inhibitors are the biggest problem, but they are also an important part of combination therapy.
• Mixing central nervous system depressants such as heroin, methadone, alcohol and benzos with each other or anti-depressants (especially MAOIs) is dangerous. This is also important if you are taking antivirals, particularly protease inhibitors, which can enhance the effect of opiates.
• Understand the interactions that can occur between illicit substances, even in the absence of HIV/AIDS or Hep C treatment drugs. You are at far greater risk of overdose if you mix benzos, alcohol and drugs such as heroin, methadone and morphine. These drugs potentiate each other - which means they make each other stronger.
• Alcohol and benzos and alcohol and heroin can cause vomiting after a person has passed out; this can cause choking, asphyxiation and death.
• Discuss your drug treatment options with your doctor - methadone, naltrexone or buprenorphine, for example. But changing treatment won't necessarily prevent further interactions or consequences. It has been suggested that methadone might encourage HIV/AIDS to multiply if it's not taken correctly as there is an increased chance of resistance occurring.
• Always inject safely with new, sterile equipment and dispose of safely.
• Whenever possible, buy your drugs from someone you know and trust. If you can't buy from a known source, test a small quantity first and wait 10 minutes to check for quality and any unusual effects.
• Use when other people are around, just in case you overdose or have another serious interaction. Be prepared to call an ambulance if something starts to feel wrong.
• Make sure someone else knows what you are using, how much and how often. If something does go wrong, they can provide this vital info to doctors or ambulance officers.
• Reduce stress on your liver by reducing the number of toxins in your bloodstream. All chemicals are potential toxins; this includes the agents that illicit drugs such as psychostimulants are cut with. In addition, reducing your general levels of stress will reduce the stress on your body and your general health.
• It might be tempting to think about stopping your Hep C or HIV/AIDS treatment while you're using, but this could be bad news and could put you at risk of developing resistance.
• Most importantly, if you think you're experiencing an adverse reaction or drug interaction, seek medical assistance immediately.