How Do CYP450 Inhibitors Work?

The cytochrome P450 (CYP450) enzymes are essential to produce numerous agents, including cholesterol and steroids. They are also necessary for the detoxification of foreign chemicals and the metabolism of drugs. Drugs that cause CYP450 drug interactions are referred to as either inhibitors or inducers.

Nowadays, the use of two or more drugs at the same time is quite common. This has the potential to cause drug interactions, thus increasing the risk of debilitating and even fatal adverse drug events. CYP450 inhibitors are used to minimize or prevent such reactions.

Drugs are metabolized in many sites of our body; however, the liver is the primary organ for drug metabolism.

CYP enzymes are membrane-bound proteins that can control the speed at which drugs are metabolized in our body and the length of time that the drug will remain in our body. If CYP enzymes are not active enough, the drugs can stay for a longer time in our body, leading to toxicity, and if CYP enzymes are overactive, they could lead to ineffectiveness of the medicines taken for various chronic diseases. Thus, the mechanism of CYP enzymes is often referred to as "A double-edged sword".

CYP450 inhibition can be categorized as:

• Reversible inhibition (a result of rapid association and dissociation between drugs and CYP enzymes)
• Irreversible inhibition (a long-lasting loss of enzyme activity)

CYP450 inhibitors are used:

• To prevent adverse events if you are on warfarin, antidepressants, antiepileptic, and statins
• As a harmacokinetic enhancer for HIV treatment: indicated to increase the systemic exposure of atazanavir or darunavir (once-daily dosing regimen) in combination with other antiretroviral agents in the treatment of HIV-1 infection

Side effects of CYP450 inhibitors may include:

• Severe toxicity
• Gastrointestinal disorders
• Genetic variability can influence CYP enzyme activity

Factors that can influence CYP enzyme activity include grapefruit juice consumption, charcoal-grilled foods, and smoking. Close monitoring is needed if CYP450 enzyme inhibitors are added to medications such as antipsychotics, benzodiazepines, cyclosporine, and statins.

The information contained herein is not intended to cover all possible side effects, precautions, warnings, drug interactions, allergic reactions, or adverse effects. Check with your doctor or pharmacist to make sure these drugs do not cause any harm when you take them along with other medicines. Never stop taking your medication and never change your dose or frequency without consulting your doctor.

Brand names for CYP450 inhibitors drugs include:

• Cobicistat
• Tybost