What is the pharmacist responsibility regarding drug interaction?

September 11, 2013 2:56 PM

An incident has happened that has me kind of upset. I am looking at it as an honest mistake, and not looking to do anything, just want to know if our experience was ... normal and expected? What IS the pharmacists responsibility to clients?

Mr. B had a toothache and went to a dentist. He wrote down all the meds he was on, with emphasis on anti-coagulant; and verbally apprised the dentist of same. He was prescribed an antibiotic, and we had it filled at the next door pharmacy, which is not our usual pharmacy, but more convenient at the time. The pharmacist started to fill the prescription, then said, you do know there is a potentially serious interaction here? I said no, what is it? She did not tell me, went to the computer and looked it up further and asked if the Dr. had known about the anti-coagulant. I said yes. Still without saying what the reaction was, she thought for a bit then said, you know what, its a really rare thing, you don't have anything to worry about. I know I should have pressed her, or looked it up myself, but I didn't.

That was a week ago, and since then, Mr. B hemorrhaged twice through the nose, lost 2 1/2 pints of blood, was taken to ER (45 miles away) twice, once by ambulance; and during the course of treatment the second time, his heart rate and blood pressure plummeted requiring some rather intensive intervention to bring him stable. (He has an extensive cardio-pulmonary history). He is now home with his nose packed because even with cauterization of three blood vessels, the bleeding continued. But, hey, he's okay, providing there are no complications when the packing is removed.

I can't help but think though that the pharmacist could have saved us all this grief (and money) by simply telling us what the potential reaction was; and suggesting that we contact our family doctor to adjust the anti-coagulant while he was on the antibiotic, which is what the various websites say to do (which I looked up while at ER and passed info on to ER doctors - who actually listened to me and checked it out themselves).

Am I expecting too much, or did this pharmacist fall short of performing her duty? And should we tell her, just so she is maybe more assertive in the future? BTW, the reaction is not all that rare, especially in elderly persons, which Mr. B is.

posted by batikrose to Health & Fitness (17 answers total)

The pharmacist is not supposed to second-guess the doctor. She did her duty by noting the potentially harmful interaction, and by asking you if you discussed it with the doctor. Once you said the doctor was aware of it, it was really out of her hands.
posted by ubiquity at 3:02 PM on September 11, 2013 [11 favorites]

Am I expecting too much, or did this pharmacist fall short of performing her duty?

She caught the interaction, checked that the dentist had been apprised of the anti-coagulant medication and deferred to the dentist's expertise. I think this is more the dentist's cockup than the pharmacist's. Drug interactions are a tricky area. If you go looking for them (on the many websites that exist for that purpose) you'll find that an awful lot of drugs that are fairly commonly prescribed are known to present at least some risk of interaction, and yet doctors will frequently, and as a matter of conventional best-practice, prescribe those drugs together. Pharmacists would pretty soon be out of a job if they refused to fill every prescription for which there was a known potential interaction.
posted by yoink at 3:05 PM on September 11, 2013 [12 favorites]

Best answer: It depends on the pharmacist.I have known some who would either contact the physician or refuse to dispense medications depending on the problem,but they are unusual (and patients and doctors have become angry with the person that I know who has done this).

If I were in your shoes, I would still report the incidence and severity of the adverse events (i.e. serious AE since it required hospitalization) to both your dentist and the pharmacist, with the objective of preventing and monitoring for this AE in other patients in the future. There are some medications that still collect this information because it may be more problematic than what occurred during clinical trials, and the goal would be to update the information and alert patients and prevent this in the future if it is the case.
posted by Wolfster at 3:13 PM on September 11, 2013 [4 favorites]

Best answer: The pharmacist did indicate some potential issues to you, although maybe not to the level of detail you now want. Of course, you could have pressed the pharmacist to tell you more about the rare interaction as well. If either of you was able to see what the future held, you both probably would have acted differently. But, the pharmacist did act within acceptable professional parameters.

The real problem is with the prescribing doctor, your dentist. The dentist was told directly about your husband's other drugs, particularly the anti-coagulant. One very popular anti-coagulant (Warfarin/Coumadin) is well-known to be sensitive to other drugs and interactions can result in major complications. This property is well-known and often acts as a red flag that should trigger extra consideration by the prescribing doctor. It sounds like your dentist dropped the ball there. Tell the dentist about the major complications so that they are more careful next time with both your husband as well as their other patients. If you're looking to find the responsible party, it's the dentist.

I'd also talk to the doctor who is prescribing and monitoring the anti-coagulant to make sure they're also aware of the events. Perhaps you can suggest to them that you'd like to get a green light from them whenever a new drug is prescribed - as a double-check for interactions and a prompt for more monitoring of your husband's anti-coagulant levels.
posted by quince at 3:40 PM on September 11, 2013 [4 favorites]

Best answer: I agree, this is the dentist's responsibility, not the pharmacist's. The pharmacist did their duty by mentioning the potential interaction, but not being privy to your partner's medical history, the pharmacist assumed the doctor and/or dentist had more/better information regarding the risk involved. Especially given that you told the pharmacist that the doctor and/or dentist was aware of the anti-coagulant prescription. The dentist dropped the ball here, and I would have a chat with them about being more careful in the future and possibly coordinating with your partner's physician if you still feel comfortable sticking with them.
posted by yasaman at 3:44 PM on September 11, 2013 [2 favorites]

Best answer: I can't comment on this specific situation (IANYD etc), but I suspect from what you describe that the antibiotic was one of the types that is known to interfere with the INR ("protime").

As a physician I generally try not to prescribe those antibiotics to people on warfarin, although sometimes for whatever reason, it happens. In those cases, I would appreciate a call from the pharmacist to discuss the interaction with me and to discuss the alternative antibiotics that would be appropriate - there are usually several antibiotic choices in any given case that would work.

The pharmacist should have called the prescriber. I've been called for much less concerning issues in a prescription than this. That said, the ultimate responsibility always lies with the prescriber themselves who knows the patient's clinical story.
posted by treehorn+bunny at 3:47 PM on September 11, 2013 [3 favorites]

Response by poster: Thanks ... appreciate the responses ... will definitely talk with the dentist on this to hopefully help others avoid the problem in the future. And yes, it was warfarin/amoxicillin. We will be more vigilant ourselves, which we should have been to begin with.
posted by batikrose at 3:47 PM on September 11, 2013

In terms of being more vigilant, I use Medline Plus. For each medication, it lists both conditions and drugs that can interact with them and give you a reason to check in with your doctor/dentist or pharmacist about it.
posted by Margalo Epps at 4:09 PM on September 11, 2013 [1 favorite]

I tend to agree it's the dentist's failure here.

One thing I do (because I trust no one) is to check interactions on Drugs.com.
posted by SMPA at 4:11 PM on September 11, 2013

This is what Drugs.com says specifically about this combo, BTW:

Using warfarin together with amoxicillin may increase the risk of bleeding, especially if you are elderly or have kidney or liver impairment. You may need more frequent monitoring of your prothrombin time or INR by your doctor to safely use both medications. Call your doctor promptly if you experience any unusual bleeding or bruising, swelling, vomiting, blood in your urine or stools, headache, dizziness, or weakness during treatment with these medications. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

(I like it because it tells you stuff like "your doctor should monitor [medical things]" - it makes medical people take me more seriously when I hand them the list.)
posted by SMPA at 4:13 PM on September 11, 2013

The pharmacist noticed the possibility of an adverse drug interaction; you assured her that yes, the dentist was informed of all Mr. B's current meds, and made the prescription anyway. If either of these professionals made an error, it was the dentist, NOT the pharmacist.

You say that you'll talk to the dentist and be more vigilant about possible interactions; you're right to be more vigilant, but I'd suggest you also find a different dentist.
posted by easily confused at 4:35 PM on September 11, 2013 [2 favorites]

Best answer: I don't think you should have to be vigilant, and I'm pissed that situations have caused you to feel that way. The dentist failed, but I feel the pharmacist failed as well -- because the pharmacist as much as predicted this would happen and then decided to dispense anyway. A nurse handing out that medication would be held responsible for knowing the adverse reaction and medicating anyway.
posted by MeiraV at 4:37 PM on September 11, 2013 [1 favorite]

At my pharmacies, they always give me a print out of drug information that includes possible drug interactions, side effects, etc. Sometimes they will tell me things like "Make sure you take this with food," which is nice, but those directions are always on the bottle and print out too.

I don't think the pharmacist dropped the ball if they saw the possible interaction and checked that your doctor was aware of it. Your dentist is the doctor who knows the medical issues at hand and failed.
posted by AppleTurnover at 5:06 PM on September 11, 2013 [1 favorite]

Best answer: Yes, I just want to point out in agreement with MeiraV that pharmacists go through a HUGE amount of training and it's not because of how hard it is to count pills and screw on bottle tops. They are considered the last in a line of defense against human errors that can lead to situations like this. The dentist screwed up but so did the pharmacist.
posted by telegraph at 6:13 PM on September 11, 2013 [4 favorites]

I personally would only blame the pharmacist if the interaction was a definite no-go. But the warning quoted above is much milder than that. It doesn't say not to do it, it just says that your doctor should be aware and to watch out for those symptoms. If the pharmacist was assured that the doctor was aware, then I can't think of a reason to blame the pharmacist.

It kind of sounds like the amoxicillin just lowers the threshold for bleeding, so there is also the possibility that the warfarin dose was too high to start with. The dentist and the pharmacist were relying on the doctor who is monitoring the warfarin to be keeping up on it too.

It sounds like an unfortunate situation that could only have been stopped by people being extraordinarily cautious. Which you can't hold someone responsible for not being.
posted by gjc at 9:04 PM on September 11, 2013 [1 favorite]

Best answer: Yeah, the reason the pharmacist is a pharmacist is so that there are multiple qualified professionals overseeing every drug prescription. They screwed up and the dentist screwed up, but if anything I'd say the pharmacist's error is worse. All medical professionals will make the odd mistake through oversight - it's inevitable. But the pharmacist specifically saw the potential for a problem and recklessly went ahead with dispensing the drug. You can't eliminate accidental errors, but you can eliminate people deciding not to do their job, and the pharmacist's job here was to be the last person who checked the prescription before it was administered to the patient. A simple phone call would have sufficed to check that the dentist was aware of the potential interaction - it's not the pharmacist's place to assume what the dentist was thinking when they prescribed the drug. If they're having misgivings, they need to check; it's what a responsible medical professional does.
posted by Acheman at 4:38 AM on September 12, 2013

But the pharmacist specifically saw the potential for a problem and recklessly went ahead with dispensing the drug.

This is incorrect. The pharmacist checked that the physician was fully informed about the medications the patient was on before prescribing the antibiotics. It is simply not the case that the pharmacist is required to refuse to dispense all medications that come with warnings about potential interactions or side effects. If they were, they'd hardly dispense any drugs at all.
posted by yoink at 10:40 AM on September 12, 2013 [3 favorites]