Why prescribe over-the-counters?

Factual Questions
1

Why do doctors prescribe medications that consist entirely of ingredients available, in the same combinations, in over-the-counter medications?

I’m thinking specifically of two instances recently when I went into the doctor’s office (for the first times in twenty years) for antibiotics to help clear up ear infections and was prescribed augmentin (an antibiotic) and in one case Humibid and in another Mucofen DM. Now the antibiotic I understand; my reason for going to the doctor in the first place after avoiding it for so long was that in this case I had developed ear infections that were not going away after several days, and I concluded that an antibiotic was called for. The Humibid was described by the physician’s assistant who prescribed it as an expectorant that would help thin out the mucus in which the ear infection had developed, allowing it to break up more quickly.

Upon filling the prescription, I discovered that Humibid was simply guaifenesin – the same expectorant ingredient that’s in practically every over-the-counter cough medicine. While it only cost me a $7 co-pay, I could just as easily have bought an OTC for $3 or $4. OK, you live and learn.

The second episode, about three months after the first, was quite similar – a cold I caught from my kids that became an ear infection – but added a serious cough that wasn’t going away readily either. This time, instead of the Humibid, the same PA prescribed Mucofen DM, explaining that it would be “better for the cough”. OK, I thought, having been ready to ask, in the event she prescribed Humibid again, why I should take that instead of an OTC medication. I got the prescription filled, paying a $15 copay this time since it was not a generic, and went home, where I discovered that the active ingredients in Mucofen DM were ::trumpet flourish:: guaifenesin again, plus dextromethorphan, the cough suppressant that’s in Robitussin, Vicks, etc. Looking at the receipt, I discovered that if I’d not had insurance, this little number would have cost me over $30! That’s for the Mucofen alone – the Augmentin was another $15.

So my question ought to be obvious: is there some factor I’m not considering that would make the formulations prescribed for me preferable to the OTC medications, or do I need to run home and consult the PDR before filling any prescriptions?

2

Couple of things I can think of off the top of my head.

  1. The active ingredients may have been much higher in the prescription version than the over-the-counter version (and no, you can’t always take 2x the regular dose.)

  2. Long before your HMO started mandating $5 or $10 co-pays, insurance companies with prescription drug plans wouldn’t pay for over-the-counter versions of drugs. Many doctors thought (and yours may still think) that giving you a prescription version would actually save you money.

If this doctor ever gives you another prescription, explain your insurance situation and ask him if there’s either a generic or OTC equivalent.