Doctors are like mothers. We tell you what to du because we assume we know better than you do.
Take medication administration, for example. If your prescribing physician doesn’t, your local pharmacist almost certainly will tell you when and how to take your prescription medication.
More often than we’d like to admit, we are wrong. Here are just a few examples:
1. ) Levothyroxine, the synthetic thyroid hormone taken by people with low thyroid function, is usually given in the morning on an empty stomach.
At least two significant studies have shown increased effect when this type of medication is taken at night. But since the dose of thyroid replacement is adjusted regularly by the prescribing physician according to a simple blood test, the timing of the dose probably doesn’t matter at all as far as achieving normal thyroid blood levels. What may be of importance is that evening dosing may more closely follow the natural diurnal rhythm of the body’s own thyroid hormone. That may be of importance for how well patients actually feel.
2.) We usually recommend heartburn sufferers to take their omeprazole and similar drugs in the morning 30 minutes before eating.
It sounds logical to give such medications before food, because eating is usually what stimulates acid production in the stomach. However, new research has shown much greater effect when these medications are taken at night. The labeling, at the pharmacy as well as from the factory that invented the drug class, still has the old dosing recommendation.
3.) We are told that cholesterol lowering statin drugs work better when taken at night.
The idea behind this is that the body produces more cholesterol at night than during the day. This has implications for when to take statins with a short half-life, like simvastatin, but isn’t a factor with long acting statins like atorvastatin, Lipitor.
Nobody knows how the timing of statin dosing affects the other mechanisms of statins, from blood clot reduction to plaque stabilization and anti-inflammatory effects.
Whether a medication is best taken with food or not is usually related to how food increases or decreases the absorption of the medication. What many doctors and pharmacists forget in this context is that the potency of the pills themselves can vary by plus or minus 20% if they are generic instead of brand-name drugs. This is all the precision required of generic drug makers in this country. That fact sometimes means more than how and when medications are taken.
Some of my patients have trouble remembering to take their evening medications; even one or two missed doses per week makes a bigger difference in cholesterol values, for example, than taking the medication at the “wrong” time would.
A medicine taken wrong is usually still a whole lot more effective than one not taken at all. I learned in medical school that patient compliance with medication administration three or four times per day is in the order of 50%. I have seen newer reports that it is better today, but I am not sure I can trust that, so I try very hard to keep my prescribed medication regimens as simple and possible. I am also less and less dogmatic about the timing of medications when the evidence that supports our standard recommendation seems shaky.