How does race affect drug metabolism?

The genetic differences between ethnic groups result from differences in the distribution of polymorphisms that are related to the enzymes responsible for drug metabolism. Even a single difference in a nucleotide of a candidate gene can have a profound impact on pharmacological response to asthma therapeutics.

What is codeine metabolized by?

Codeine is metabolized to morphine by the cytochrome P450 enzyme (CYP) 2D6. Inhibitors of this enzyme (such as fluoxetine and citalopram) can decrease or even abolish the effect of codeine.

How does genetic factors affect drug metabolism?

Genetic polymorphisms have been identified for many drug-metabolizing enzymes, including the cytochrome P450 (CYP450) enzymes. This gives rise to distinct population phenotypes of persons who have metabolism capabilities ranging from extremely poor to extremely fast.

What does it mean to be a poor metabolizer of a drug?

Poor Metabolizer. A poor-metabolizing enzyme has very low activity. It is possible to have side effects even with a very low drug dose, because the enzyme is very slow to break down the drug. Rapid or Ultrarapid Metabolizers. These enzymes are very active, often breaking down drugs before they can have any effect.

Is race important in medicine?

Despite the absence of meaningful correspondence between race and genetics, race is repeatedly used as a shortcut in clinical medicine. For instance, Black patients are presumed to have greater muscle mass than patients of other races and estimates of their renal function are accordingly adjusted.

How is codeine activated in the body?

Codeine Application Codeine, an alkaloid obtained from opium or prepared from morphine by methylation, is a widely used analgesic medication. Codeine must be activated by conversion to morphine through a demethylation reaction mediated primarily by CYP2D6 to produce analgesia (see Fig. 11.3).

Why do people metabolize drugs differently?

Some drugs are chemically altered by the body (metabolized)… read more ) drugs slowly. As a result, a drug may accumulate in the body, causing toxicity. Other people metabolize drugs so quickly that after they take a usual dose, drug levels in the blood never become high enough for the drug to be effective.

What is meant by drug metabolism?

Drug metabolism is the chemical alteration of a drug by the body. Some drugs are chemically altered by the body (metabolized). The substances that result from metabolism (metabolites) may be inactive, or they may be similar to or different from the original drug in therapeutic activity or toxicity.

How do you know if you are a rapid metabolizer?

Intermediate metabolizers have low or reduced enzyme activity. Extensive metabolizers have normal enzyme activity. Rapid or ultra-rapid metabolizers have high enzyme activity.

How do you know if you’re a slow metabolizer?

Likely, your body is giving you signs that can clue you into where you fall on the great coffee divide. Slow metabolizers can get jittery and stay wired up to nine hours after drinking caffeine, according to Precision Nutrition. Meanwhile, fast metabolizers simply feel more energetic and alert for a couple hours.

How is codeine metabolized in the human body?

For codeine to exert its opioid activity, it must first undergo o-demethylation by CYP2D6 to morphine. Only about 5-10% of codeine is metabolized in this pathway, with about 80% of an administered dose of codeine being converted to inactive metabolites and excreted.

How is the effect of codeine similar to morphine?

The onset and duration of effect are similar to morphine. It is administered via the oral route. The conversion of codeine to morphine is effected by CYP2D6.

How is codeine used in the treatment of pain?

Codeine is used to relieve mild to moderately severe pain, and it belongs to the drug class of opioid analgesics. The hepatic CYP2D6 enzyme metabolizes a quarter of all prescribed drugs, including codeine. CYP2D6 converts codeine in to its active metabolite, morphine, which provides its analgesic effect.

Can a CYP2D6 UM metabolize codeine to morphine?

In contrast, individuals who have more than 2 normal-function copies of the CYP2D6gene (“ultrarapid metabolizers”, UMs) are able to metabolize codeine to morphine more rapidly and more completely.