A large percentage of the population in America take more than one prescription medication and over 30% also take dietary supplements regularly. Many people are not aware that drug interactions may occur between their medicine and nutraceuticals, and these could have a negative impact on their health.



Despite frequent reports in the newspaper on the latest health scares, we have benefited hugely from advances in both pharmaceutical and nutritional sciences. There is now a huge selection of medication and health supplements for our therapy and massive research is being undertaken into new cures and treatments.

Using Drugs and Supplements Together

Almost eight percent of Americans aged 18 to 44 take three or more prescription drugs daily. In seniors of retirement age this figure rises to nearly fifty percent. Other statistics show that over a third of adults in the USA use health supplements on a daily basis and almost a fifth have used a natural product over the past year.

It does not take a genius to work out that a large amount of people are taking drugs and dietary supplements at the same time and they may not be aware of drug interactions. This statistic is made more worrying by the fact that, according to one study, 70% of patients do not tell their physician that they are self medicating with an alternative treatment for their health concern. Conditions such as like allergies, obesity, arthritis, colds and flu and are now so common place that physicians may feel less inclined to investigate the persons own strategy for treatment. This is compounded by the fact that many people think that doctors will not understand their decision to use alternative treatment. For some of these people drug interactions can pose problems.

Lack of Knowledge about Drug Interactions with Supplement

Some famous cases in the media highlighting the side effects of drugs as well as the strict regulations concerning the marketing of drugs mean that most people are aware that drugs can have complications. To a lesser extent drug interactions are reasonably well known and your doctor as well as your pharmacist will generally make sure that you have not been prescribed a detrimental combination of medications. There are also regulatory and an ethical incentives for pharmaceutical companies to discover any possible drug-drug interactions. The situation is different when it comes to nutraceuticals and herbal supplements. Little research has been conducted into drug interactions with nutraceuticals. Physicians will usually play it safe if asked by telling patients not to take supplements to avoid drug interactions. This is partly due to the scant formal training for herbal products or nutraceuticals in medical school and the general distrust of the nutrition industry by the medical profession.

How do drugs and supplements interact?

After taking a drug and this then reaching the bloodstream, there are a number of ways that it can be cleared from the system. A major clearance pathway is through the liver. Certain enzymes in the liver will be responsible for the breakdown of certain drugs. These specific enzymes may also have the task of breaking down other substances that have been ingested including alcohol, nutrients and elements of herbal products. If the enzymes responsible for breaking down say paracetamol, are also responsible for breaking down a supplement you have taken previously, the enzymes will be busy with the supplement and the paracetamol will be left to float in the bloodstream.

Pharmacokinetics of Consumption

Problems with drug interactions can arise when the therapeutic window (the difference in concentration of a drug in your bloodstream between no effect, desired effect and harm) is short. A dose is a highly calculated amount so if this is thrown off because your enzymes are tied up dealing with supplements or something else then your drugs may not be working properly. Additionally, if you are taking multiple doses of the drug in a day and it has a long half life (the time it takes to decrease to half of the original concentration in your blood stream) then you will effectively be topping up the concentration of the drug which can lead to dangerously high levels and possible overdose.For example, calcium channel blockers such as felodipine (Plendil?) for high blood pressure or congestive heart failure are broken down by the same enzymes as quercetin, a flavonoid found in grapefruit juice but also available as a supplement. Regular use could easily increase the levels of the drug in the body and cause accidental overdose levels - despite taking the recommended dosage at the right times.

Supplements Can Enhance the Effects of Drugs

Drugs and dietary supplements can also have a synergistic interaction effect when taken at the same time. They can produce similar pharmacological effects in the body or enhance the effect of one another through some . This can of course be dangerous to your health. The dietary supplement garlic is now very popular for atherosclerosis and cardiovascular problems. Garlic thins the blood and patients who are undergoing surgery or who are taking anti platelet agents (drugs used to stop the blood forming clots in the heart) can then have problems with blot clotting appropriately upon trauma to a blood vessel.Useless Drugs

Some dietary supplements can also induce the enzymes in the body to be more "active" than usual - they can have what is called an "inductive effect". The enzymes are then much more efficient at clearing any prescribed drugs from the body. The drug dose is calculated so that enough of the drug is in the bloodstream for long enough for the active ingredient to be effective. If such drug interactions occur then the drug passes through the system too fast and may have a reduced effect or no effect at all.

Further Information on Supplement Drug Interactions

The first rule it to tell your doctor or pharmacist what nutritional supplements you are taking and why. They may be able to advise you of possible drug interactions with your supplements. Unfortunately, there is not a great amount of understanding in the medical profession about herbs and nutraceuticals, especially the interactions between supplements and drugs.

However, some research has been conducted into the popular herbs such as St. John's Wort, Ginseng, Gingko, Ginger and Garlic.A dietician may have better knowledge than your doctor but there are many websites on the internet that you can get more information about drug interaction. See our for these sites.