Significance of Cytochrome P450 in medicines?

Question

Is it bad to take a medicine that is an inhibitor with a medicine that is a substrate? Or 2 inhibitors of the same enzyme?

Answer 1

I would need to know a little bit more about the medicines, and what medical condition(s) you are targeting with them.

Cytochrome P450 is pretty common in the human body. Drug metabolism (how quickly a drug gets broken down) is a common use for it in meds.

Both an enzyme inhibitor and activator can bind to the enzyme in question. A substrate is just something that binds to an enzyme. Enzymes can have multiple binding areas, and this is how enzyme inhibitors work. When an enzyme inhibitor binds to an enzyme, it causes a conformational change in the structure of the enzyme. This means that other substrates (proteins) cannot bind to the enzyme, so there is a greater concentration of these proteins around. This slows the reaction rate of the type of enzyme as a whole.

If you are taking an inhibitor for a specific enzyme along with an activator of the same enzyme, it could just cancel the other out. I am not sure about this, as there may be a reason to have an enzyme in one part of the body more activated, and in another part of the body less activated.

Depending on what the enzyme is doing, it may  be beneficial to use two inhibitors of the same enzyme. You would need to speak to your doctor or pharmacist about the specific medicines. If the enzyme is a very common one, or undergoes different reactions with different substrates, it may be good to use to two different inhibitors. This would possibly ensure that the enzyme will be inhibited as much as possible,  or for two different reasons.  A large dose of one or the other may be toxic, and so using a smaller dose of two different drugs would be possibly less toxic.

I would not take anything in duplicate that is not prescribed by your doctor, as many over the counter meds are to be taken independently for a condition, and should never be mixed. Talk to a pharmacist at your local drug store for specific medicine usages.