path: OSCE database
If you have files you would like me to host on here and share with others, please email them to me. [email protected]
path: PRESCRIBING
If you have files you would like me to host on here and share with others, please email them to me. [email protected]
Prescribing is an integral part of a General Practitioner’s work and several high profile cases have been published when qualified doctors have made catastrophic errors. Because there are a large number of patient deaths relating to medication errors. The only way this will improve is if we start regularly reviewing and analysing our prescribing habits. The best way of looking at an identified need is to pause and reflect on what we are doing rather than bury our heads and just continuing as we are. Would you agree?
We know GP trainees appear to assessed left-right-and centre. But this is another important area where we can better ourselves. Qualified GPs and their practices are often asked to look at their prescribing habits in some way or another and we feel therefore trainees should too.
Yes. All trainees in ST3 have to do one. There is no set standard as it is designed as a learning exercise; however if no errors are highlighted and if no learning is identified this would raise concerns, as to date this has never been the case.
For the official MRCGP prescribing tools and supporting documents to help you, see the resource items under the QUICKLINKS section at the top of the page. They are reproduced below for your convenience.
If you have a prescribing pearl to offer, please submit it via the comment box below and I will add it to the list.
What is it?
When we mention the cytochrome P450 system, most doctors just want to turn around and run away! So, let’s demystify it once and for all. The cytochome P450 (CYP45) system is basically the liver’s enzyme system. The CYP450 is so called because it is found within the membranes of a cell (hence CYTO). It contains a haem pigment (hence CHROME and P). And it absorbs light at a wavelength of 450nm. It has quite a number if functions…
Why is it important?
Because so many drugs (including nutrients and herbal therapies) are metabolised via the CYP450 system. This system can be inhibited or induced by drugs. And that then leads to drug-drug interactions and all sorts of adverse reactions. Drugs that cause CYP450 drug interactions are referred to as either inhibitors or inducers.
And what makes it worse, is that there is genetic variability in about 7% of people. For example, many clinicians believe that post menopausal women recieving tamoxifen for early breast cancer should be tested for their type of CYP2D6 genotype as it may be valuable in selecting the type of adjuvant homonal therapy to offer. And of course CYP2D6 inhibitors should be avoided in tamoxifen-treated women.
And patients come to us with often co-morbidity. It would be nice if the world was just full of people with just the one thing. But it isn’t. It’s a lot more complex. It’s not uncommon for a patient withy hypertension and bad lipids to present to us at some point with depression, for instance. Did you know that several antidepressants are CYP450 inhibitors (i.e. reduce metabolism of other drugs). The effect on drugs like halperidol or metoprolol will then be accentuated.
In the case of grapefruit juice, there are numerous medications known to interact with grapefruit juice including statins, antiarrhythmic agents, immunosuppressive agents, and calcium channel blockers. Furthermore, the inhibition of the enzyme system seems to be dose dependent; thus, the more a patient drinks, the more the inhibition that occurs. Additionally, the effects can last for several days if grapefruit juice is consumed on a regular basis. Luckily, the effect of this is not seen with other citrus juices.
Examples of INDUCERS
(i.e. speeds up metabolism of other drug, so it may not be as effective)
Mnemonic: SCRAP GPS
Examples of INHIBITORS
(i.e. slows down the metabolism of other drug, so it’s effects may be accentuated)
Mnemonic SICKFACES.COM G
