People with HIV can also experience diarrhea and vomiting. These can cause antiretroviral drugs to be expelled from the gut too quickly, reducing the amount of drug absorbed into the bloodstream. Varying Pharmacokinetics Pharmacokinetics is a term used by researchers to mean how a drug is absorbed, distributed, metabolized, and removed from the body. Even though two people might receive the exact same dose of a drug, the amount of drug may be higher in one person's bloodstream than in the other person's bloodstream. Factors that can contribute to this difference include their body weight, height, and age.
Some people also process, or metabolize , drugs faster or slower than others do.
In other words, some people may be able to keep their viral load undetectable using lower doses of the drug, while some people might require higher doses of the drug to keep their viral load undetectable. In the future, healthcare providers may begin performing blood tests to measure the amount of drug in their patients' bodies. This is called therapeutic drug monitoring and it may help determine whether or not a person has a correct trough level of each medication to ensure that viral load remains low or undetectable.