What is a Drug Interaction?

A drug interaction is a medical condition that results from the combined effect of taking different drugs at the same time.

Drugs are broken down (or metabolized) in the body by the liver. Some of the potentially dangerous interactions between some HIV drugs and some other drugs result from the drugs being broken down by the same enzymes in the liver. The effect of this is that when both such drugs are present the liver takes much longer to break them down. This can result in dangerously high levels of the drug/s circulating in the bloodstream.

Some drug interactions can be dangerous. In some cases they can be life threatening.

Drug interactions may also result in increased side effects from some drugs, and/or they may prevent your HIV medications working properly.

It is important to tell your HIV doctor about other prescription and recreational drugs that you may take.

Interactions Between HIV Drugs and Recreational Drugs

Drug interactions can occur between HIV drugs and other prescription or over-the-counter drugs, some herbal and alternative treatments and also between HIV drugs and recreational (illicit) drugs.

There can be dangerous interactions between Ritonavir and many amphetamines (such as crystal, Ecstacy, MDA) and cocaine. Ritonavir slows the processing of these drugs by your liver, which can result in dangerously high levels of the amphetamines in your blood.

Alcohol can react badly with treatments containing the HIV drug Efavirenz, such as Stocrin and Atripla.

For more information about potentially dangerous interactions between HIV medications and recreational drugs, go the the NAM treatments Directory.

Interactions Between HIV Drugs and other Drugs

Viagra can react with protease inhibitors and non-nucleoside reverse transcriptase inhibitors (NNRTIs). Talk to your doctor about the appropriate dose of Viagra; in most cases people should take a much smaller dose of Viagra than normally prescribed.

Antihistamines, statin drugs and indigestion treatments can also interact with HIV drugs.

Methadone can can react with some HIV drugs (eg. Efavirenz and AZT). The effects can be like a methadone withdrawal. Your doctor may need to consider a different dosing strategy.

St John’s wort (a herbal antidepressant) can lower blood levels of NNRTI drugs. Garlic capsules can stop the protease inhibitor saquinavir (Invirase) from working properly, and may also affect other protease inhibitors.

What are the Symptoms of a Drug Interaction?

They can vary widely, depending on the drugs mixed. For example, taking alcohol with sleeping pills can cause dangerous drowsiness and loss of consciousness. Sometimes drug interactions can cause symptoms similar to drug overdoses, but they are also capable of causing a very wide variety of symptoms.

Some of the possible symptoms and the warning signs are :-

• Severe sudden drowsiness or feeling like ‘passing out’
• Feeling extremely nauseous
• Vomiting
  

If you think you are experiencing a drug interaction you should get urgent medical assistance. Paramedics and Ambulance officers will not normally get the police involved in drug overdose matters; they treat them as medical matters, not legal matters.