One of the things that you learn in medicine is that using single medications is better than combinations. However, for years over the counter medications have used a mixture of medications. Each one of those was aimed at a single symptom that the patient might be having.
The logic was that it was better to take one dose of medication than it was to take multiple doses of medication. While taking a single dose might make it easier to take the medication, it certainly was not as effective as a treatment.
For example cold remedies often contained multiple medications. Sometimes they contained a decongestant aimed at stopping a runny nose. Sometimes they contained an antihistamine aimed at treating nasal stuffiness. Sometimes they contained things like Tylenol to reduce fever. Sometimes they contained an expectorant to make a cough looser, and other times they contained a cough suppressant to stop a cough completely.
Most preparations contained many of these. That created several problems. The first is that most patients did not have all the symptoms that the medication treated. Thus they were taking medication that they did not need.
The second is that most of the preparations contained lower doses than if the medications were taken separately. That means that the patient was probably taking too low a dose for it to be effective.
Until 2006 the decongestant that was most commonly used was pseudoephedrine (Sudafed). It was very effective. For most upper respiratory infections it was the only medication that was actually needed or helpful. It was a common over the counter medication.
However, drug abusers had found a method to take pseudoephedrine and chemically convert it to methamphetamine an addictive drug of abuse. It grew to such proportions that pseudoephedrine was taken off the over the counter market in 2006.
Manufacturers decided to replace it with another decongestant called phenylephrine. Phenylephrine had long been used as a topical decongestant. It went by the brand name of Neosynephrine nose drops. I sometimes used them in infants with colds so I would not have to use oral medications.
Phenylephrine works very well topically. However, when it is taken orally and has to go through the digestive tract, it doesn’t work. So from 2006 on, I always told parents that it was a useless medication when in a cold preparation.
Lo and behold, last week the FDA agreed with me (17 years later) and decided that it needed to be taken out of over the counter medications.
I still keep Sudafed (which now comes from the pharmacy rather than over the counter) on hand for upper respiratory symptoms. During my recent bout of COVID, Paxlovid, Tylenol and Sudafed did the trick.
The convenience of multiple medications in one preparation really does not offset the lack of effectiveness when they are all used together instead of separately.