In what way do Pharmacists in the US or similar countries exercise professional discretion? I don’t think they have the authority to second-guess the prescribing physician and dispense a different drug, do they? How often to pharmacists have to perform on-site chemical synthesis (e.g. "the prescription from the doc says the patient gets 33.3 mg quadrol, but I don’t have any. I think I remember that it can be synthesized from aspirin, prozac, and HCl according to this procedure published in <some scientific journal>) ?
IANAP. Drug store pharmacists are not synthesizing anything, the most technical they get is mixing a drug from a concentrate to a diluted solution. Compounding/hospital pharmacists are also not synthesizing compounds either, but they may be mixing drug cocktails, making IV solutions or making customized formulations of drug for customers with allergies to ingredients normally found as fillers in pills.
A pharmacist is not a physician and cannot prescribe a medication. A pharmacist can call a physician and tell them that the patient cannot/should not take drug X for whatever reasons (allergy, drug interaction). They physician can then amend the prescription.
Drug synthesis is not easy. It cannot be reliably performed in a pharmacy from the raw ingredients found there. There would be too many issues of purity and contamination for it to be practical, not to mention the chemicals needed to make/purify/isolate pharmaceuticals are pretty hazardous.
The professional discretion of a pharmacist is not to gossip. He or she cannot go around the neighborhood telling other people that the minister is taking Antabuse, or the prosecuting attorney takes enough prescribed painkillers to knock out a horse.
A pharmacist must know a helluva lot of math. Granted, computers in pharmacies do the work these days, but the foundation of everything is being able to calculate dosages and dispensing quantities. If a customer is obtaining prescriptions from different providers (family doctor, specialists, dentists), the pharmacist needs to know what can be taken together and what is potentially lethal to the patient. The pharmacist also needs to be knowledgeable about over the counter medications and how they mix or don’t mix with prescription meds. It’s a complex job, and it includes a lot more than just counting pills.
~VOW
Don’t pharmacists also watch out for drug interactions the physicians may not be aware of?
They also can recommend alternate dosages / forms / schedules if something’s not in stock, or it’s significantly more cost effective.
For example, your doctor may prescribe Brand Name drug X in 500 mg twice daily. Your pharmacist may be able to tweak that around into the 300 mg version of the generic 3 times daily, or something like that.
But, what actually happens if the pharmacist is concerned about what the patient is taking? Do they do something like this:
(drug names are made up because I am too lazy to research actual drug interactions)
“Hello, is this Dr. Smith? This is James Jones, the pharmacist down at the Quality Corner Drug in Marysville. I am a little concerned about this recent prescription you wrote for Molly Brown for 10mg daily hypertemol. She told me that she is also taking 50mg of marekine from an ENT specialist, and, according to a study done at Johns Hopkins in 2005, taking marekine at the same time as hypertemol results in a 500% increased risk in developing heart disease and a 200% increased risk in developing bipolar disorder. I’d like to recommend that you give her blarkorin instead. It’s been prescribed for 20 years and there have been no reported concerns with interaction with marekine or other marekoid drugs.”
Can the pharmacist refuse to dispense the drug that the physician prescribed if the pharmacist thinks the drug will harm the patient?
According to My Dad the Pharmacist, if the pharmacist thinks a patient will be harmed by a drug they are ethically obligated to refuse to dispense it. So the answer is “yes”.
Some pharmacists have refused to dispense the Morning After pill, or even birth control pills, on what they consider to be moral grounds. And some pharmacies have refused to carry such medications. There’s been a great deal of discussion about this.
From my uncle, who was the head pharmacist for a large chain of department stores: Pharmacists do this regularly. We even had computer systems that kept track of the prescriptions for each patient, and would give us a warning if there were any drug conflicts. Then we call the doctor, and tell them about this. But we wouldn’t go into details about the study unless asked.
And we would never do the last part – “I’d like to recommend …”. That would be considered very rude & presumptive, and doctors are touchy. If the doctor asked about a substitute, or seemed confused about what else to prescribe, you might say “I have some blarkorin in stock, and that’s been used to treat this condition”. But the doctor has to be the one to order the prescription.
Sometimes the doctor would stay with the original prescription. They would have been aware of the drug interactions, but considered them less serious than the patient not getting this medication. That’s their medical judgment. Then the pharmacist would make a detailed note in the patient records, stating that they spoke to the doctor about possible drug interactions, and doctor renewed the order for the original prescription. And they would be extra careful in giving the patient the usual instructions about possible side-effects, and when to stop taking the medication and call their doctor, etc. Probably explicitly warning that this drug has been known to interfere with another drug you are taking, and you need to be watching for this.
But the pharmacist has to either give the drug as prescribed, or refuse altogether. Refusal probably would have been done earlier – while on the phone with the doctor, they would have told them that they will not fill this prescription for that patient. That was quite rare.
It’s worth noting that like physicians, pharmacists have to spend an inordinate amount of time dealing with insurance companies.
And even that sometimes gets screwed up. Avastin has been linked to blindness in a number of cases in which the same Florida pharmacy handled the drug.
In Quebec the pharmacist can substitute a generic. When my wife’s 5 mg pills of some medication were unavailable one month, the pharmacist cut 10 mg pills one month. Then the idiot did the same thing the following month, though the 5 mg pills were again available. (A different pharmacist in the same store confided to me that, “Jack is just not paying attention these days and just repeated the previous month’s prescriptions without thinking about it.” Maybe he thought we were saving money that way. I have always regarded Jack as somewhat dim. A week or so ago, I heard a third pharmacist explaining to Jack how to compound a prescription. Jack is the oldest pharmacist there (and used to be the owner until he sold it to a chain).
Changed “to” to “do” in title.
They also need to be good at decoding cat scratches. I have no clue how Steve knew what to me looks like -</P /-=L was “Hydrocodone 200mg, as needed” (or something like that).
That’s a hell of a lot of hydrocodone. It’d put down most non-addicted persons for sure. Cats, too.
That’s why I put the “or something like that.” 
Think of the cats, though. 
Won’t sommebody think of the kittens!!!
I was told that this is part of the reason that prescriptions are now done electronically. That is, if I mention to my doctor that I’m out of Hydrocodone, he’ll tap on his keyboard for a couple of seconds, and send a prescription or refill authorization to my preferred pharmacy.
And jeez, MY prescription is for 10 mg tablets, and they are so effective that I won’t take them until I’m ready to climb into bed in less than 2 minutes.
And I always think of the cats.
I used to get really bad migraines. In high school was getting them a couple times a week. Our family GP kept proscribing me painkillers (I think it was prescription strengh tylenol, not something like vicodin). Eventually our pharmacist told my mother (& the doctor) “We aren’t going to be filling any more prescriptions of (drug); it’s going to destroy his liver at the rate he’s going through them”. I ended up seeing a neurologist and getting put on Topimax.