Have you ever wondered why, sometimes, even the seemingly most effective drugs aren't doing too well in alleviating your symptoms? Well, the human body is capable of a great many things, including traits such as drug tolerance. The body getting used to a specific drug could be seen as the cause of medication suddenly becoming ineffective. But what about medication that you've never used? Another cause might be that the drug you're using undergoes drug metabolism.
Drug metabolism is the process by which an external drug is altered by the body chemically. Typically, this process occurs when the medication reaches the liver, though not necessarily. The enzymes in the liver break the drug down to its basic chemical components, or as close as the body can get to them. The drug metabolism process can often make the drug ineffective for a variety of reasons. The breaking down of the drug into separate chemical components can render some medications ineffective, because it relies on the interaction of the compounds as a single unit to have an effect.
However, not all medications are rendered useless by drug metabolism. The pharmaceutical industry has several medications that are designed to take effect once metabolized, effectively using the body's natural functions to bolster the drug's effect. In cases of medications such as this, the components are designed and selected to function once freed from other compounds in the formula. These extra compounds, known as metabolites, can either be further metabolized by the body or excreted appropriately. It should be noted, though, that even these medications may not always function properly.
Genetics are a major factor in the interactions between the drug metabolism of the body and the medications that people put in. Some people are simply genetically programmed to have faster or stronger drug metabolism systems in their livers, which can render even the best-designed medications absolutely useless. Others have such weak metabolisms that drugs designed to be released after being metabolized are never fully broken down, resulting in everything being excreted by the body rather than being absorbed. In such cases, doctors might choose to recommend a drug that is known to have similar effects but reacts differently to the body's metabolism. For example, if you've got a faster metabolism, he may decide to give you medication that is harder to break down.
Age can also play a role in whether or not the body properly metabolizes any medications put into it. The enzymes that do this task are not fully developed at birth. The human body acquires the needed enzymes as it ages, so newborns and children might not be able to fully metabolize some medications. This is part of the reason for several types of drugs, such as cough and headache medication, have variant formulas specifically for children and adults.
The metabolic rate can also be considered in determining the dose that should be administered. Since children have smaller bodies and slower metabolisms, smaller doses are required to avoid an overdose. In contrast, adult bodies can handle larger doses and more potent concentrations. However, past a certain age, the metabolism begins to slow down and the need to use smaller doses returns.