Dr. Rassman,
I have been taking 2% topical minoxidil since late December 2005. I have ALWAYS taken more than the recommended doses. I would estimate at first 2-3 times the amount, later on 4-5 times the amount. By mid March I noticed my sex drive was really low and and I had a harder time getting and maintaining an erection. I read online from the Mayo Clinic that too much absorption of topical minoxidil can lower sex drive and performance. I have stopped taking it for a week and sexually I’m better, but not quite normal. I also still have some heart palpitations. Could you please tell me when my body will “clear-out” the excess minoxidil?
Some drugs are metabolized fairly quickly, while others can take a long time before they are eliminated. We quantify this with the use of the term “half-life.” The half-life of a given medication is how long it takes for the body to get rid of half of the dose. When the patient is taking a medication on a regular basis, there is an ongoing process of drug absorption in the form of each dose of the drug and, concurrently, an ongoing process of drug removal with the drug’s metabolism and clearance. Eventually, there comes a point when the amount of drug going in is the same as the amount of drug getting taken out. We call this “steady state.” It takes somewhere between 5 and 6 half-lives for a medication to reach steady state. Thus, medications with short half-lives reach steady state relatively quickly, while those with long half-lives take a long time to reach steady state. Minoxidil has a blood half-life of about 4 hours, but I can not determine how long it hangs around the kidney, heart, or other organs when it is out of the blood. Most of the good studies are on oral administration of the drug for treatment of high blood pressure and here is what I read on RxList.com: “The extent and time-course of blood pressure reduction by minoxidil do not correspond closely to its concentration in plasma. After an effective single oral dose, blood pressure usually starts to decline within one-half hour, reaches a minimum between 2 and 3 hours and recovers at an arithmetically linear rate of about 30%/day. The total duration of effect is approximately 75 hours. When minoxidil is administered chronically, once or twice a day, the time required to achieve maximum effect on blood pressure with a given daily dose is inversely related to the size of the dose. Thus, maximum effect is achieved on 10 mg/day within 7 days, on 20 mg/day within 5 days, and on 40 mg/day within 3 days.” This may be more than you asked for.
If you have heart palpitations, you should be seeing a doctor about that. This is a worrysome problem, something that is far too important than to take it to a doctor like me who advises on general questions over the internet. Minoxidil may be out of your system by now and the fact that you are getting better is good, but having a heart problem needs prompt and proper medical treatment, so get it to see a doctor ASAP.
2006-04-21 12:32:012006-04-21 08:34:04How Long Does Minoxidil Stay In My Body?
