Tag Archives: interactions

Common Holiday Season Drug Interaction Warning
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The holidays can increase the consumption of two drugs that we may use in a light to moderate fashion during the year, either at separate occasions or concurrently.   One of these drugs is alcohol and the other is acetaminophen. Sometimes the consumption of alcohol results in adverse effects that require the use of the second drug, or perhaps the acetaminophen is just used regularly for any type of chronic or acute pain you may be experiencing.

The two main organs in our body that help to remove drugs are the liver and the kidneys. A series of chemical reactions occur where drugs are changed or “metabolized” to make them readily removed from the body, often through the intestines or the urinary tract.   Without these organs, most drugs would quickly reach toxic levels, resulting in death.   We are constantly bombarded with online offers to “boost” the detoxifying powers of both organs to improve health – a concept completely unproven and a certain red flag for someone looking to detox your money from your wallet.

It is common knowledge that alcohol is metabolized for removal from the body largely by the liver. Repeated over-consumption of alcohol, especially over the long term, can lead to liver disease. Acetaminophen is also heavily metabolized by the liver, and large doses of this drug, even in a single dose can have devastating effects on this organ.   For the most part, in the average healthy individual, light to moderate intake of alcohol will not cause damage to the kidneys or the liver. The same holds true for acetaminophen in regular doses of 3000-4000 mg per day, even for extended periods of time. In fact we often see studies that seem to indicate that light consumption of alcohol can have some benefits. Keep in mind that this should never be a reason to start consuming alcohol in any amount when you never were before though as alcohol does have some adverse effects on the GI tract associated with it.

Recent evidence however has determined that the consumption of acceptable levels of both of these drugs at the same time can and has lead to serious kidney disease in otherwise healthy people. The effect was of greater probability in older adults (who often have reduced kidney function), males, blacks and Hispanics (over white patients), and those with conditions that can typically reduce kidney function like diabetes, high blood pressure and obesity. This news can come as a shock to those in the medical community who automatically look toward the liver as the weakest link in the metabolism chain for these two drugs. In fact I regularly tell patients to avoid acetaminophen in “hangover” situations as there have been documented cases of liver damage when the two have been taken together. It turns out, that life threatening kidney damage can occur even in the absence of liver disease when they are combined.

The recognized risk is that there is a two-fold increase in kidney dysfunction when these two drugs are combined even at acceptable doses. Keep in mind that many combination products in the over the counter section of the pharmacy contain acetaminophen, including cough and cold and sleep products. There is an increased danger when these medications are consumed and not reported to your pharmacist at the time you are purchasing them. You may be taking acetaminophen already in a prescription product that is combined with an over the counter medication containing the same ingredient. Some patients may also metabolize acetaminophen at a significantly slower rate than others, magnifying the problem. Changing your pain reliever to an anti-inflammatory (NSAID) like ibuprofen or ASA may be no better after alcohol consumption as the increase in inflammation in the lining of the GI tract can result in a serious GI bleed. Using codeine for pain relief is never recommended with alcohol on board.

The take away message here is if you are someone that is taking acetaminophen (or an NSAID or codeine) for pain, you are better off avoiding alcohol consumption even in light amounts. If you are someone with chronic or acute pain to the degree that one of these medications is needed, remember that the adverse effects can be quite sudden rather than gradual, and the use of lower dosages as recommended.

 

 

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What’s the real reason for not counselling and missing interactions?

Lately we have heard stories of Pharmacists not doing their job correctly.  To be exact, in a survey of a sample of pharmacies, it was discovered that medications that are kept in the pharmacy but did not need a prescription, there was insufficient or completely absent counselling on behalf of the pharmacist.  These medications are in a special class in that they can only be sold in a pharmacy, behind the counter of the dispensary, and the customer must ask for the medication in order to be screened for interactions with existing medications and medical conditions, as well as proper use of the medication so that it is safely used and gives the best results.

Although there were arguments that the sample size used in this observation was too small to make an overall conclusion, just 50 pharmacies, and that the study was not scientific, showing even one pharmacy not counselling this type of medication is not good.  As pharmacists we don’t shoot for a certain percentage of jobs done correctly across the country in the run of a day.  We more importantly look at any incidence of improper counselling and try to better ourselves by looking at why we didn’t do our job correctly.  Undoubtedly spurred on by a few recent reports of dispensing errors across the country, this survey began in BC and spread across the country based on the results in that one province.  Trust me, when a pharmacist makes a mistake, it hits them like a ton of bricks, regardless of the outcome.

This nationally broadcast report was fuelled by a week long buildup that caught the eyes of pharmacists and general public alike.  Word began to spread in the New Year about the story and certainly when it finally came to air, there was a huge reaction from those who watched it.  Many pharmacists chimed in.  Initially claiming unfair reporting in that it made pharmacists look completely inept.  Others claimed that the story completely avoided the good that pharmacists do that is totally ignored for the most part.  This was followed by examples of what we do as pharmacists every day.  The reporter afterwards quickly claimed that the show was more about quotas imposed on pharmacists to increase script count than exposing pharmacists not doing their job correctly.  It was certainly a perception of mine leading up to the program and certainly after watching the program that the latter was the case.

As someone that works for an independent in a small community, the concept of pressure imposed by quotas for increased prescription count is definitely foreign to me and one I must admit I had never heard of before.  Pharmacists interviewed for the program claimed that this pressure to increase script count was responsible for other parts of their job slipping, including counselling these behind the counter medications and focussing properly on the filling and checking process.  Let’s suppose this were true, and maybe it is.  Then obviously it is something eroding pharmacy that needs to be addressed.  These pharmacists interviewed pointed to the problem of non pharmacists  now able to own pharmacies – something new over the last couple of decades.  The profession of pharmacy is certainly not against change, but the change we have seen over the last 20 years has absolutely lead to great things, but in some cases has also lead to the erosion of the profession.

Before I graduated from the College of Pharmacy in 1993, things were strict.  You kept things professional by not being able to advertise “free prescription delivery”, you couldn’t connect any incentive to a prescription like “points” for your prescription purchase or bonuses for transferring your prescription file to a pharmacy, you couldn’t say “accurate prescription filling” because it was unprofessional and implied someone else had inaccurate prescription filling, among other strict rules.  Gradually, we saw big box stores start to include incentives to their employees when they had their prescription filled at their banner, then drug plans that are affiliated with the pharmacy with restrictions that you are covered when you get your prescription filled only at that pharmacy chain and no other.  While on the subject of third party plans, in my opinion the most dramatic effect overall in the pharmacy business today, we have seen a very gradual undermining of the pharmacy business because dispensing fees and reimbursement to pharmacy from the third party plan has not grown with what is reality in dispensing.  Dispensing has become a volume business in order to show a real profit.  In fact we are starting to see decreases in dispensing fees from third party plans.  In a lot of ways I feel these plans are a part owner in my business.

A sweeping move initiated by provincial governments across the country was a huge hit to the bottom line of pharmacies, like Nova Scotia’s Fair Drug Price Act.  A move that seemingly made sense to the general population in that it aimed at lowering prescription prices by coming up with an imaginary dollar value for various popular generic medications, regardless of what the pharmacy paid for it.  This move came about from the practice of generic companies giving rebates for purchases, a common practice in many types of business.  The government saw this as their money.  These were the main dollars we used to run the programs of our pharmacy and the dollars we used for donations and community programs that came to us for help.  Very quickly this money was gone.  In effect, this attempt by the government to lower prescription drug prices was accomplished on the backs of the pharmacies in the provinces.  Our communities are now realizing the effect of lack of income in their community pharmacies.  Before too long, we saw other third party plans jump on this bandwagon, and gone were more dollars we used to run health programs we conceived on our own for the health our community.

Enter the expanded scope of practice.  We as pharmacists were allowed now to write prescriptions in certain cases of minor ailments, extend existing prescriptions, do med reviews, injections, adaptation of prescription, and order and interpret lab tests.  The reason was we can charge for these services to make up for what we were losing on the other end with rebates.  Definitely this is an honourable theory: make money for actually doing something that helps with the health of our patients.  The problem being that there was now no money to run these new services anymore and most plans weren’t on board with paying for them .

One might argue, “then why not just drop your affiliation with third party plans?”  Then we could set our own prices bases on our own pharmacy needs and staff levels .  Small town low volume stores could have better control over their income and not allow third party plans to control what they earn on a prescription.  Instead of getting paid 12 dollars for a prescription that costs 15 dollars to fill, you could charge what you paid for the drug and a fee that allows the dispensary to make money on its own regardless of the front shop.  Well we do this because it allows our patients to afford their medications and they probably fill more prescriptions for their health when they have coverage, not to mention that all pharmacies not dropping plans means patients shop for pharmacies that take these plans.

This brings us back to the original issue of why are we dropping essential counselling and why are we too busy to catch interactions?  Well perhaps the pressure we should be looking at isn’t the pressure to fill more prescriptions, it’s the pressure imposed by third party plans on the pharmacy whereby they don’t make enough on each prescription to pay for itself in the first place.  Maybe this is the reason for the “quota” being imposed on pharmacies to fill more.  The lack of reimbursement forces any pharmacy to scratch for more prescriptions since they cannot afford to hire the staff to run these extra programs and give time to the pharmacist to do their work of not only bettering health, but preventing harm from meds.

To top off the issue of missed interactions because of lack of time, consider the thought process involved with each and every prescription when the possibility of the patient dying from the medication exists each time a prescription is filled.  The side effect of any  medication is death and there are so many side effects and potential warnings on any given medication it would take an hour to explain them all to each patient.  On top of that, the sheer volume of prescription interactions with other meds or disease states makes the evaluation of these interactions an art that is not just based on book smarts, but also on clinical experience.  If there is a 0.00001 chance of a dangerous interaction occurring do you call the doctor, alert the patient and change the drug?  Is the evaluation of these interactions a black and white science or is it based on followup with the patient on their overall health and history.  Recently I wrote a blog on a type of interaction called prolonged QT interval ( https://stonespharmasave.com/blog/?p=694 ) that describes the complex evaluation involved with just one interaction.  There are thousands of such interactions to evaluate for each fill and you reset your brain when you fill the next prescription.  If I give you a prescription there is a very slight chance you might leave the pharmacy, take the medication, have an adverse reaction or interaction with another medication and die.  Perhaps I will be on the evening news for not telling the patient this.  Do I tell you this?  Not necessarily.  But if I evaluate the probability of this reaction occurring then I am in a better position to act on it.  When we take off in an airplane do we sign off on the fact that it might crash?  There is inherent risk in taking any medication.  It’s our job to make sure you have the best possible medication and outcome from that medication.

Getting back to the lack of counselling in these behind the counter medications – guilty.  We accept that.  The more pharmacy and pharmacies are left to be run by corporations (big box stores and third party plans) and not pharmacists, the more and more this profession will erode and show up on more undercover specials.

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Long QT Syndrome
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Without a doubt one of the more prominent medical issues to watch for not only with individual drug administration, but with drug interactions as well is the problem with Long QT Syndrome.  It appears that over the last 20 years this crops up more and more.  The issue with this syndrome is that most people don’t know if they have this medical problem or not.  Although some people have had themselves hooked up to an EKG at some point in their life for an unrelated issue and this problem would have been caught, most haven’t and when this drug/disease or drug/drug interaction pops up, we are left wondering how to deal with the problem.

In measuring the electrical activity of a heartbeat, a typical sinus rhythm should show up.  There are distinct landmarks on the graph: P,Q,R,S,and T.

The interval between Q and T is the time it takes for the electrical impulse to flow through the lower chambers of the heart until the heart is ready for its next beat.  If this interval is longer than normal, it is called Long QT syndrome.

One of the frustrating things is that this syndrome is that it may not be present all of the time.  It may only be present during times of stress, exercise, cold water on the face such as when swimming, auditory stimuli, when you are startled, it may be during the night when sleeping, or it may be caused by certain medications.  This syndrome may be inherited or acquired.  Theses patients often have no symptoms.  They may have a history of fainting, seizures, or an abnormal heart rate at times.  The danger is that the syndrome can lead to cardiac arrest or sudden death.

Not everyone metabolizes or handles drugs the same way.  In some of our testing procedures we find that some of us metabolize some medications very fast or very slow. Some take a medication for sleep that gets metabolized so fast it can never work to put them to sleep.  Others metabolized so slowly that they are completely hungover in the morning from one pill at bedtime.  This shows that we are all different when it comes to our response to medications and how some people will experience long QT from one drug and some don’t or that a long QT side effect occurs from a drug/drug interaction in one person and not another.

These individuals should also avoid the following agents:

  • Anesthetics or asthma medication (eg, epinephrine, lidocaine)
  • Antihistamines (eg, diphenhydramine)
  • Antibiotics (eg, macrolides (azithromycin(4)), quinolones, trimethoprim and sulfamethoxazole, pentamidine)
  • Antidepressants (tricyclic, citalopram, trazodone, venlafaxine)
  • Cardiac medications (eg, quinidine, procainamide, disopyramide, sotalol)
  • Decongestants
  • Gastrointestinal medications (eg, domeperidone (1), metoclopramide(3))
  • Antifungal medications (eg, ketoconazole, fluconazole, itraconazole)
  • Psychotropic medications (eg, tricyclic antidepressants, phenothiazine derivatives, butyrophenones)
  • Potassium-loss medications (eg, indapamide, other diuretics; medications for vomiting/diarrhea)

Risk factors for drug induced LQT syndrome and TdP include: female gender, concomitant cardiovascular disease, substance abuse, drug interactions, bradychardia, electrolyte disorders, anorexia nervosa, and congenital Long QT syndrome, elderly population, history of fainting or seizures. Careful selection of the medication and identification of patient’s risk factors for QTc prolongation is applicable in current clinical practice.(2)  At www.crediblemeds.org there is an invaluable source that is updated regularly to help the clinician evaluate the dispensing of an offending drug so that you and the physician aren’t left guessing on the potential seriousness of the interaction.  Registration is free but it is a great resource to have in your back pocket.

This is certainly an important interaction to be able to evaluate and share with the physician.  Being able to make recommendations makes you a valuable member of the healthcare team

1. http://www.ncbi.nlm.nih.gov/pubmed/20394569

2. http://www.ncbi.nlm.nih.gov/pubmed/20210726

3. http://www.pharmacologyweekly.com/articles/how-does-metoclopramide-increase-the-risk-of-qt-interval-prolongation-and-polymorphic-ventricular-tachycardia

4. http://www.ncbi.nlm.nih.gov/pubmed/24285766

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