Pharma Help: Understanding Drug Interferences


A drug interference is a change in the action or side effects of a drug caused by concomitant administration with another drug, supplement, beverage, or food product. There are all kinds and types of drug interactions that can result in competition for a single receptor or signaling pathway, altering the intended effect of that particular drug.

The two main types of interferences are pharmacodynamic interactions and pharmacokinetic interactions:

Pharmacodynamic Interactions

This occurs when one drug alters the responsiveness or sensitivity of tissues to another drug by having an agnostic or antagonistic effect. Typically, this process usually occurs at the receptor level but can occasionally occur intracellularly.

Pharmacokinetic Interactions

Conversley, this can occur when a drug alters the absorption, distribution, protein binding, excretion, or metabolism of another drug. The amount and persistence of available drugs at the receptor site can change as an effect. Rather than affecting drug type, this kind of interaction can alter duration and magnitude. Additionally, pharmacokinetic interferences are often predicted based on knowledge of individual drugs or by monitoring drug concentrations and clinical signs.

Obviously, this kind of work is not for everyone and can be quite difficult to even comprehend for those with little-to-know experience in the pharmaceutical sector. Thankfully, there are plenty of helpful worksheets out there that can help with drug interference experiments. The Clinical and Laboratory Standards Institute (CLSI) has developed documents that can help experimenters and researchers follow along with their guidelines and recommendations to help simplify the process.

Whether you’re experimenting with triglyceride concentrations or the various dextran sulfate uses; knowing what steps to take is a crucial part of the experimentation process. So be sure you’re following any helpful documents as accurately as possible.

Lastly, it’s important to note that many drug interferences are due to alterations in the drug’s metabolism. Human drug-metabolizing enzymes are typically activated through the engagement of nuclear receptors. Cytochrome P450 oxidases, a metabolic drug interaction system, can affect steroids, sex hormones, enzyme functions, and so much more.

Here are a few popular food products that can influence drug metabolism:

  • Avocados, brussel sprouts, broccoli, and cabbage — enzymatic inductor that affects Acenocoumarol and warfarin.
  • Ginger — in vitro affecting Anticoagulants.
  • Garlic — increases antiplatelet activity in NSAIDs and Anticoagulants.

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