How do doctors decide on the amount of dose they prescribe? Do have some formula or chart for every scenario?

Question

How do doctors decide on the amount of dose they prescribe? Do have some formula or chart for every scenario?

Answer 1

There are dose-ranging studies in phase 2 of the pre-marketing trials for each drug as it goes through the approval process before it can be placed on the market. Then there are studies once the drug is available, often for off-label indications. We just keep all this information in our heads. Of course, nobody can keep up with all the doses for all the drugs for every problem, but a few thousand combinations isn't much, considering all the other stuff that's rattling around in our noggins. After all, you don't even get into medical school unless you've shown an ability to digest massive amounts of information.

Answer 2

drug company tells them based on factors like age, weight, and gender

Answer 3

During clinical trials, the drug companies test for safety, but they also test for "efficacy".  The results from the studies will tell them what doses are generally beneficial without causing unwanted adverse effects or wasting drug. When the drug is being  approved by the FDA, it's approved at those doses for the recommended indications. This list of doses is what is marketed to the doctor and placed on the drug prescribing information sheets.

The doctor can either go with this recommended dose, or use their "best judgment", based on previous experience. Doses can also be adjusted if the patient has liver or kidney problems, or is taking other medications which might interfere. In such cases, the doctor usually refers to a pharmacist for their opinion. In complicated cases, this can often involve regulars meeting to discuss the patient's needs.

But if you walk in to your doctor's office and they write you a prescription for some antibiotics or something, they're usually just going by what the drug companies tell them to write.

Answer 4

It is based on the body weight of the individual so there is not an overdose.

Answer 5

To put it simply, it's not rocket science... we have these lovely books which provide guidelines on drug dosages.  With experience, a physician can become quite astute with determining which dose of a medication will be most appropriate.  With some medications, we have to monitor serum drug levels to make sure that it's within the normal range.  In pediatric patients, most medications are administered in a weight-based manner.

Answer 6

What is needed is the age and condition of the person being treated along with the weight to figure the dosage.

Diabetes and heart patients of 60 and 135 Lbs. can't take the same dose of something (say for a cold) that a 25 year old that is healthy and weighs in at 200.