I know that some overdoses are results of user error.
How many overdoeses, however, are results of manufacturer error? I understand there are QC mechanisms but there always exists the possibility that drug X which was supposed to be a 10 mg capsule escaped QC mechanisms and ended up being a 15 mg capsule and poisoned a user.
Are you only including stuff like 10mg pill actually contains more drug - or are you including when a pharmacist mixes the drug (as is done with some cancer drugs and the like) on a doctors order?
I’ve heard of the later happening, and stuff like this: http://www.fda.gov/Safety/Recalls/ucm336107.htm
Leads me to believe the former has probably happened as well, but I’d bet money it is less than 1% - way less would be my guess.
This American Life addresses the question in one specific case. Infants Tylenol is stronger than Children’s Tylenol, and being prescribed one instead of the other has led to fatalities.
The story also addresses the standard dosage for Tylenol as possibly being too high.
Relatedly, Citalopram’s standard dosage used to be 60 mg, but led to heart attacks and was lowered to 40 mg.
But manufacturer error specifically? I think that would be restricted to small batches caught by the manufacturer, not widespread system failures. The industry is simply too strictly regulated.
I am not a doctor, pharmacist, or other healthcare professional, but I do know that most if not all drugs (don’t know about the ungodly expensive ones for certain cancers and rare diseases) are made in large batches. So, if a 10 mg capsule failed QC and ended up being 15 mg, it won’t be a single person getting OD’ed; it will be many people.
This is my thought too - if a mixing error resulted in a lethally strong pill, the result would be found very quickly - and likely result in complete recall of the brand. Plus, I assume quality control is applied, testing a sample of every batch. You cannot be too careful when you are talking about potentially fatal medication.
As for proper mixing, to avoid “veins” of super-strong medication concentrations being pressed into overdose pills - I assume the mixing technology has been tried and tested and is known to not do this. I once did a quick network survey for a pill plant, and the precautions and clean-room activities were quite strict.
As for size - the ingredients are mixed together and pressed into specifically sized pills. It would be very difficult to press an oversize amount. As for capsules, the amount again is sized to the capsule volume. You might get 50% more in the capsule, but it’s not like it’s 80% empty in any ones I’ve seen.
Plus, how many medications except exceptional ones are dangerous at 150% of regular dose? I imagine those are subject to serious quality control. Most of the problems you read about are people taking 5 or 10 times the dose.
From what I’ve read, the majority of medication problems are human error. (one report, IIRC, suggested around 10% to 20% of hospital medications are in error) Apparently it happens a lot more than you think, especially at busy hospitals. The dose level for an injection is especially prone to error, since it is a fluid. The doctor may mis-prescribe, the pharmacist or nurse may misread the prescription, mistake a decimal point or measure… Or they grab the completely wrong bottle. Even a harmless mistake can be lethal if the patient is not getting the medication they need.
That’s a lot more likely than the pill-making machine churning out quadruple-dose pills.