What Is The Right Dose?

By Author: Steven Johnson
Total Articles: 494
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In theory, everyone is the same except, obviously, they are not. Let's start with age. Seniors may be physically active but, look inside, and you will find their liver and kidneys are not working as well as in days gone by. This means it takes longer for impurities to be filtered out of the blood. For these purposes, drugs are impurities. So, when an older person takes any medication, it's processed through the stomach into the bloodstream and then circulates for longer. This means an older patient must either take a smaller dose or the time between doses must be longer. If such simple steps are not taken, it's easy for older people to have peaks of drug concentration close to overdose levels. Adverse side effects are more common.

At the other end of the age scale, most drugs are not tested on children and young adults. It's not considered ethical to expose underdeveloped human bodies to the risk of injury unless there's a clearly identified need. As a result, doctors are often left guessing whether to risk prescribing drugs and opting for the lowest possible doses. Now we come to the politically incorrect question of ...
... body weight. Without getting into the speed of your body's metabolism, thin people should receive smaller dose than those carrying more weight. Doctors often use a formula relating grams to pounds of weight.

A further difficulty is that pain is very subjective. Some people seem to be able to accept levels of discomfort that would have others rolling on the floor in agony. This is partly physical and partly psychological. As we grow up, we learn from our parents and peers how we are supposed to react when injured. Boys are supposed to be tough. It's OK for girls to cry. Stereotypes are difficult to shake. This makes it very difficult to assess how much pain anyone is feeling. All a doctor can do is ask and try to place the answer on a scale of 1 to 10 where 10 is the worst pain imaginable. The louder the complaint, the higher the dose or the stronger the drug. For the doctor, it's all trial and error until the patient admits to feeling less pain. Against this background, it's interesting to see some new research into using a new technique on an MRI scanner to measure pain. Arterial spin seems to show changes in the parts of the brain associated with pain. If this research can map the brain to show more precisely which part of the brain to monitor, it may be possible to produce a more objective method for measuring pain.

This would have immediate benefits for the patient, always giving the right dose. It would also be good for society because it would reduce the risk of drug abuse. As it is, patients who are developing a dependence can exaggerate their reports of pain and get additional tablets to feed their habit. This is less of a problem for drugs like Tramadol which are significantly less addictive than the opiates. But even Tramadol can be abused if people take it for too long at too high a dosage. No matter what the diagnosis, it's always better to have the right dosage for your age and physical size.