In the community if a patient is only on one medication such as a SSRI, say Fluoxetine, (Prozac) it's rather easy to switch to another newer SSRI, escitalopram (Cipralex). There's a rough equivalence between 10 mg of Prozac and 10 mg of Cipralex. However, because Fluoxetine as a long half life (the length of time before the medication is half metabolized) 10 mg may in fact represent more like 15 or 20 mg. At the same time over time there is a natural resistance to medication that occurrs at the cellular level requiring increasing dosage of medication to achieve the same effect. There are various names and explanations for this, such as 'tolerance' etc but the fact remains a patient commonly on a very good antidepressant will present saying the 'medication isn't working'anymore. Most commonly the 'stress' in the patients life has quadroupled but sometimes really , nothing has changed but over time the medications' efficacy has reduced.
At this point the first strategy is to increase the medication and this may go on to when the benefits of a medication are outweighed by it's side effects. Prozac is commonly 'topped' by 80 to 100 mg with the consideration that as the dosage of a medication is increased outside the manufacturers specifications the liability of the clinician increases exponentially. The Prozac manufacturer says the medication is safe to 60 mg for instance but some of us have used it to even 120 mg though the risk of 'serontonin syndrome' is considerable.
Hence, the usual need for a change of a medication is when the one medication is 'topped out'. However, the way a medication works at 'high dosage' is different than it's working at low dosage so again there is little 'equivalence'.
In practice in the community, I titrate down a medication dropping by increments, in this example of 10 to 20 mg while increasing the other medication by 10 to 20 medications until I've replaced one with the other. Each change is given a few days or a week sometimes simply because that's the length of time it takes to see the effectiveness or likelihood of side effects or because practically that 's the scheduling of the clinic.
Fortunately in antidepressants the newer antidepressant is perceptually more potent because of the lack of tolerance. Hence 100 mg Prozac could be replaced by 40 mg of Cipralex. That's the advantage of the shift.
Often though the original medication has been 'augmented' with alternative medications which increase the efficacy of the medication. Examples of augmentation for SSRI medications include low dose lithium, low dose thyroid medication, low dose ritalin, and low dose mood stabilizers, anti anxiety or antidepressant medications. Each of these medications has a differential response to the old medication and the new medications.
None of the text books or pharmaceutical references address the complexity of this so that not uncommonly the augmenting medications are cut first. Cutting a medication is often extremely frightening and disruptive to the patient who not only is physiologically committed to the medication (like stopping chocoloate, tea or coffee) but psychologically is committed (it was oncea life saving addition). This 'withdrawal' experience is itself difficult and consequently generalists are quick to add medications but commonly refer the case to specialists when all the 'fixes' are used up and the patient needs to have essentially an 'overhaul'.
The university hospital is a treat because invariably they suggest a 'wash out' , stopping all medication for 1 - 2 weeks and then starting the new medications. This is when the community based colleagues look at their academic associates and ask who is more psychotic the patient or the doctor, simply because such resources are rarely available, the cost is extraordinary and the rest of us out of academia including patients have to work for a living. Patients are only willing to go through 'wash outs' as last resorts because effectively they're going to experience all the terror and depression and even hallucinations during that time. They will have nurses and doctors 24 hours present but they're be 'feeling' the raw sensations themselves.
So in the community we practice the 'art' of medication. Today with an aging population the patients are not only on the 2,3 or 4 psychiatric medications but not unusually a similiar set of medications from two or three other specialists as it often takes a 'team' to keep these marvellous sports car bodies of ours doing the amazing laps we continue to do into the 80's in the rat race of life when we should all be dead or off fishing and golfing by the age of 50 with street urchins, childrens and slaves of any country holding the fans so we don't have to exert ourselves and then don't have to see doctors, rest, sun and good diet with lots of sex with young athletes and spiritual exercises for half the days utilizing our time.
Each of the medications affect another medication. So my patients on methadone can be killed quite easily by my increasing the seizure medication Tegretol or adding clonazepam to the mix to help with sleep. Methadone has a small window of safety in terms of respiratory function and any medication that effects this can cause asphyxia. Alcohol and marijunania and a number of over the counter preparations such as antihistamines are as likely to create death as any of the pharmaceuticals. The same goes with a variety of the arrhythmia stabilizing medications used in the treatment of heart disease especially after a myocardial infarction.
The greatest problems arise when doctors don't know what the patient is taking. This includes illicit drugs and 'herbs'. Herbal medications counteract the effect of antibiotics and until scientists discovered this no one could understand why certain patients were dying from otherwise treatable infectious diseases.
That said, there are references. As physicians we study these references and frankly wish that the drug dealers, and sometimes the alternative health care providers would study the subject as well given they are commonly making a lot more money than we are and only have a limitted training requirement to ours while presenting themselves as 'authorities ' and commonly telling patietns they don't 'need' something or that 'it will be okay' if you add a bottle of whisky to your psychiatric medications and your heart medications.
The Michael Jackson case was a tragedy that thankfully has culminated in the Hollywood doctor being tried for malpractice. Sadly he probably was trying to work 'with' the rather egocentric and demanding superstar who like so many patients is often 'non compliant' or 'non adherent' to medical advice.
As a person who has had tickets for speeding and know that speeding is one of the principal causes of death in traffic accidents and I'm flossing resistant as well, despite the best efforts of my terrific dentist and his wonderful dental hygeinists, I don't judge Michael Jackson, his doctor, or the patients who don't do what they are 'supposed to do'. Mostly we all get away with it. The retrospectoscopy is send in medicine to be an adaptation of the proctoscope for use by the same.
It's just that this factor needs to be introduced to the equation because non compliance results in a deviation from the ideal usage of medication by anywhere from 10 to 30% some of which is compensated for by the safety designs of the medications.
In the end, patients are living longer fuller healthier lives and science has not only cured countless diseases, extended life and put men in space it continues to come up with ways to assist us in dealing with the complex interactions of medications and factors of medicine. For the last decade I've used computer programs that are good for 2 or 3 medications and while they don't deal with the 'soup' they do help me mostly with not interfering with medications used for the treatment of cancer, arthritis, or other systemic diseases which are commonly associated with life preserving medications. Several of the medications I use specifically affect diabetes and insulin efficacy and I have at least a dozen diabetics in my psychaitric practice.
I can check Mirtazepine interaction with insulin by punching in some names on my Epocrates program on my iphone. Unfortunately it takes time. All the advances in medicine take time. The greater the complexity and this is true with aging populations and sicker patients the greater time required and the greater trained individuals but the fact remains that its usually unsupported. So each day I make an ethical struggle with looking up something or explaining something or cross referencing something and every week or two I see a patient who says,
"You don't seem to know very much. My other doctors don't ever look things up. They don't explain things and talk like you do. They listen and then give me a prescription. They don't waste my time. I can get in and out of seeing them in 5 minutes and I don't get a parking ticket. You not only don't know what you're doing but can't do it fast at all. I'm fed up with doctors like you. They should teach you something at those schools that gave you all those fancy pieces of paper."
Yes, you're right. That's what I tell the licensing bodies, the auditors, the lawyers, and everyone else. I wish somebody had taught me something. But then, I had the best teachers and a whole lot of my patients wouldn't have been alive today or more importantly enjoying good lives if all we did and knew was what I learned 25 years ago in school. Every year I'm doing 2 to 4 weeks of upgrading and it's still not enough. Only the computer scientists in my practice grasp the significance of the advances in the pharmaceutical industry. We commiserate about viruses and anti viruses and 'fixes' and 'beta' systems.
It's the best we can do and when I really sit back and think of it, what I'm a part of is miraculous. I'm really thankful to all the people involved in the process of helping me and the patients have the tools to address their illness.
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