How strong are OTC drugs?

If you listen to TV commercials for over-the-counter medications, they invariably include the line “Prescription strength, now available without a prescription” or some such. I always thought that drugs available in prescription strength required a prescription because of their strength; what about them has changed to allow them to be sold OTC?

Are we in danger of weaning ourselves to become more accustomed to stronger medications, thereby ultimately requiring even stronger ones?

What causes a medication to pass muster & go from prescription to OTC?

In general, “strength” isn’t a very meaningful term in pharmacology. It’s just too vague, except in very restricted cases. (Like comparing a 325mg asprin vs. a 150mg asprin.)

It’s common for people to refer to one antibiotic as “stronger” than another, but it would be more accurate to say either that the one is wider-spectrum (kills more breeds of germs) or that it is more specific (more deadly to the specific germ you’re infected with). These are actually quite different, almost opposite, but people often use "stronger’ for either one (maybe without even understanding the difference).

Also, listening to TV commercials isn’t a very good way to get the straight dope on much of anything!

But the ads imply (when they don’t come right out and say it) that you’re getting the same mg per dose in the OTC variety that you used to be able to get only with a prescription. For instance, my brother used to get a prescription for Claritin for his allergies. Eventually his doctor told him he no longer needed a scrip for it, because it was available, same dosage, same strength, in the drug store.

My point is, you hear this all the time. If it is safe enough to make it widely available w/o a scrip, why was it originally available only under a doctor’s orders?

Incidentally, I try to avoid listening to TV commercials whenever possible. But eventually my wife gets sick of me grabbing the remote to surf during the ads, so we sit through them. And I know that the Dopers are always there to pull me through.

The same thing happened recently with Nexium. Originally they used it only as a perscription for heartburn. After using the drug for a while they found that it had hardly any side effects. This is why they decided to make it OTC. I think a lot of times it just has to do with the fact that they simply do not know enough about the drug yet to make it widely available. Once they learn how the drug effects people in the mid to long terms they sometimes make it available to everyone. As far as strength if you take twice the amount of Advil recommended on the bottle then you have yourself the perscription strength (roughly twice the normal mg). This isn’t a rule for all drugs though.

Nexium IIRC is still prescription. Its sister drug, Prilosec, is now OTC. Pharm companies will do this often – subtly change the chemistry to make a drug slightly better, repatent it, and continue to sell it under prescription. Competitors can’t make generics, people with health insurance often like prescription drugs better than OTC because they can get the drugs covered, etc. This is what happened with Claritin and Clarinex and Prilosec and Nexium.

Whether a drug is prescription in the USA depends on the FDA. The FDA keeps all new drugs prescription only for a few years because this allows more medical monitoring. Basically, there are three FDA phases of clinical approval for a drug. After Phase III trials a drug is submitted for approval and the FDA decides a drug can be marketed and released by the pharmaceutical company. It then enters what is termed Phase IV or post marketing surveillance in which the drug is investigated on a larger scale while given to people in the population at large. I am unclear of the bureaucratic steps, but after a set number of years, the FDA reviews the complications and adverse effects associated with the drug and then decides whether it is safe for OTC release.

And I think it has to do with the fact that all of them (drug companies, doctors, pharmacists) can make a whole lot more money if it is kept as a prescription drug.

But this is now getting into IMHO territory, rather than GQ.