One Size Fits All Doesn’t Work in Medicine

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In medical school we are taught that there is one dose of a medication that will treat any patient, no matter how tall, how thin or fat, male or female, 18 to 90 years of age. For a profession that prides itself on training very intelligent people this dictum seems ridiculous!

When we learn pharmacology (writing prescriptions for medications) we learn that for adults, oral antibiotics have one dose for a particular problem. For example, for an adult of any size, age or sex, Z-pak (Zithromycin) dose is 250mg in each pill, dosed two in the first day and one per day for the next 4 days for bronchitis. It is no wonder that one 5 day pack is adequate for me at 130 lbs, and 5 ft 3 inches, and is NEVER adequate for my husband who is 250 lbs and 6 ft 4 in. It is inevitable that my husband has to go to the doctor twice for every respiratory tract illness and get two different antibiotics one after the other because the first one doesn’t work, so he is put on a more advanced one, Levaquin at 500 mg, once a day for 10 days. That generally works, but the first trial possibly gave him a bacterial resistance to zithromycin because it didn’t kill the bacteria, it only “wounded it”. In terms of time and money, this one size fits all system doesn’t work!

In a world where we have our own special playlists on itunes, we wear a particular size shoe and dress, why is medicine so backward and out of touch on this issue? I think it is because we do many things in medicine the same way our predecessors did, without a thought! Doctors follow the rules and do what they are told, instead of asking themselves the important question, “Why do the big people require 2 office visits or more and 2 or more different medications when “normal size” people don’t?”

In hormone replacement I was trained that women with a uterus got Premarin 0.625 plus Provera 2.5 mg daily. If that didn’t cure their symptoms then I could increase the Premarin dose to 1.25. Never was I told that women over 200 lbs needed the higher dose to begin with, but that is what I experienced in private practice until 2002 when I began to use individualized bio-identical hormone replacement therapy. For pellet therapy I had to determine the dose of my patients from the outset. For this, I had to figure body size, BMI, activity level, other drugs that might stimulate the breakdown of the hormones as well as guess at the activity of aromatase enzymes genetically determined as well as liver activity in the p450 system. All of these factors are taken into consideration when I begin a dosage of estradiol and testosterone pellets in a woman. In men there is a greater variation in height and weight so that factor takes precedence when determining dose for men.

Because of my hormone replacement practice, and individualized dosage, I began to review the one size dosages I was using for other drugs. This changed how I prescribed for the big and tall man, the obese or over 5 ft 10 woman, and for women under 100 lbs, and my dosages rarely need adjustment when I consider the weight and height of my patients. I’m a practicing physician, who deduced this by “practice” and learning to individualize dosage with hormones. I wonder when mainstream medicine will decide it is time to consider dosages for different weight classes.

The last factor that affects the dosage of medicine that you may need are determined by genetic factors. We are just beginning to be able to test your genetics for whether you need a normal dose or a high dose of medication. For example the saliva genetic test is available to see if a patient needs a normal or higher dose of blood thinners, or if they won’t work at all! There is also a genetic test to see if you will have severe side effects from statin drugs for high cholesterol, so patients won’t have to take the drug, endure severe muscle damage and pain because currently trial and error is how doctors determine genetic incompatibility with a particular drug.

In the next ten years (I hope) there will be saliva tests that determine what optimal dosages are, and what medications we can and cannot take—individually. Until then, those of you who are very tall, big or small should ask your doctors this question before you try to fit in a one size fits all medication. You will save time and money as well as decrease your sick days by getting the right dose for your size the first time!

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