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Drug Interactions with Glivec

Hi,

Has anyone ever used this site   

http://www.medicines.org.uk/guides/glivec/leukaemias%20(chronic,%20myeloid)#medicines

to check if you are taking anything that interacts with your meds? I just did and one of the things listed in an antibiotic that I have just been prescribed, Erythromycin, yet the GP checked in his book before giving it to me.

Who is right I wonder, the P's' book or this site?

Generally I would trust my doctor to be right and internet advice to need some caution but I would also ask my haematologist. On that score, I note the website lists paracetemol as a drug that may interact with glivec - i have been told by haematologists I can take paracetemol but in moderation - ie less than the usual daily maximum.  Not because of interaction but because of not wanting to overload the liver. I've also been told to avoid ibuprofen - because glivec and ibuprofen are both a bit harsh on the stomach. 

I was also interested that in the "diet" section, no mention was made of the need to avoid grapefruit.  Has this advice been changed?  It was one of the first things I was told about Glivec before I began taking it, and the label the pharmacy puts on the packet stresses this.

I think it is quite worrying that they do not list Grapefruit under the diet section. I have found the "Contact Us" section on the site and will drop them a note to suggest they check. I'll update this thread if/when I get a reply.


Alastair

That's a good idea Alastair, I'd be interested to know how reliable and up to date this site is.

J

Dear All,

It might be useful to understand who governs the site and where they get their information from.

If you click on 'who they are' you will find the following infromation.  I think that reading this list that you should always refer to the information provided by expert CML clinicians and maybe also the information provided directly by the company that produced the drug.

Sandy

 

The Medicines Information for People Board is a unique collaboration of groups with a shared vision to provide good quality, reliable medicines information for medicine users, their carers and the general public in the UK. The Board, which includes members from the Department of Health, the NHS, the pharmaceutical industry regulator, the pharmaceutical industry, and professional and voluntary health organisations, is responsible for overseeing the development of the eMC Medicine Guides website.

The Medicines Information for People Board includes members from the following organisations:

Association of the British Pharmaceutical Industry (ABPI)

Datapharm

Department of Health

Faculty of Pharmaceutical Medicine (of the Royal College of Physicians)

Medicines and Healthcare products Regulatory Agency (MHRA)

NHS Choices

NHS Direct

Parkinson's Disease Society

Proprietary Association of Great Britain (PAGB)

Royal College of Nursing (RCN)

Royal Pharmaceutical Society of Great Britain (RPSGB)

UK Medicines Information (UKMi)

University of Leeds

if you click on the http://www.medicines.org.uk/guides/pages/about-emc-medicineguides you will find out who owns the site/who funds it etc.

I note that most pharma companies are funders and so would be giving some input about their own drug products. As Olivia has pointed out there is no mention of the interation with Grapefruit which might be because this would be classed as an interaction with food. However, this is a good example of why we as patients need to be vigilent in who's advice we decide to follow. 

Sandy

I have copied below the response I have received from medicines.org.uk below. I have checked the leaflet which comes in the Glivec package and there is no mention of avoiding grapefruit. Not sure where to go with this now. Alastair

 

Thank you for your enquiry regarding Glivec. The information on the Medicines Guides websites is based on regulated documents called the Summary of Product Characteristics (SPC), supplied by pharmaceutical companies. These normally mention any restrictions for taking the medication which is in turn reflected within the Medicine Guide.
 
You may wish to contact the distributing pharmaceutical company; the staff there may be able to provide further information for you.  Contact details as follows:

Novartis Pharmaceuticals UK Ltd
Medical Information Direct Line: +44 (0)1276 698 370

Medical Information e-mail: medinfo.uk@novartis.com

Customer Care direct line: +44 (0)845 741 9442

Thank you for your enquiry; we are sorry that we cannot assist you further on this occasion.

Kind regards,

Datapharm Support

 I have never been warned off grapefruit. I am on dasatinib and tend to have a glass of grapefruit juice most mornings before taking my tablets with water. I had my second BMB this week and was told not to take ibbruprofen because it can affect your platelets. In the past I have been told to avoid it because it is processed by the liver. I have been told that paracetamol and lemsips are ok for infrequent use. I asked about taking echinacea to support my immune system but was told by my nurse who took advice from the pharmacist to avoid this because of possible effects upon the liver and they were not sure how it worked on the WBC....

I also asked about certain foods - like stilton cheese, ready meals etc after some research I had seen about the risk of infection to blood cancer sufferers generally - not just cml - but the conclusion seemed to be that so long as I was keeping well that would be fine, and that sort of advice was more pertinent to BMT people. But it can be quite confusing trying to get the info and strike a balance with it all.

I am on imatinib - the only thing the Hammersmith told me I must avoid is grapefruit.  no great loss for me as I don't like it. 

As a participant in the Spirit 2 trial, my Imatinib boxes come with a label showing a printed instruction to avoid both Grapefruit and Grapefruit juice.

 

My Haemotologist has advised that I don't take paracetamol, but use Ibuprofen instead, as paracetamol interferes with the metabolisation of Imatinib.

 

 

David.

I am going to double check with my nurse and consultant again as I'm getting a bit confused and concerned now.

Glivec is broken down by the CYP450 enzyme in the gut and the liver, as is Erithromycin.  Grapefruit is a potent inhibitor of this enzyme and so slows down clearance giving you higher blood levels for longer.  Taking the two drugs together would mean both were competing for the same enzyme so again clearance times could be longer.

Does it matter?  That depends on how well you tolerate the drugs in the first place.  If you are borderline intolerant then anything that ups the blood levels is bad news.  If your body tolerates the drugs well then it probably makes no odds.  For me I just drink my grapefruit juice in the morning and take my Glivec at night.

Its the Pollen season here in Norway now, and i`ve always taken Zyrtec(CETIRIZINE DIHYDROCHLORIDE), is this safe to take together with Glivec for a few weeks?

Many drugs can interact with imatinib. Below is just a partial list that I found on eMC Medicine Guides

I have not been able to find a note of interaction between Zyrtec and Glivec. Please check with your haematologist, but it is likely that this preparation- anti-histimine? - would be OK.

Best wishes,

Sandy

Taking other medicines
If you are taking more than one medicine they may interact with each other. At times your prescriber may decide to use medicines that interact, in other cases this may not be appropriate.

The decision to use medicines that interact depends on your specific circumstances. Your prescriber may decide to use medicines that interact, if it is believed that the benefits of taking the medicines together outweigh the risks. In such cases, it may be necessary to alter your dose or monitor you more closely.

Tell your prescriber the names of all the medicines that you are taking so that they can consider all possible interactions. This includes all the medicines which have been prescribed by your GP, hospital doctor, dentist, nurse, health visitor, midwife or pharmacist. You must also tell your prescriber about medicines which you have bought over the counter without prescriptions.

The following medicines may interact with Glivec:

carbamazepine
ciclosporin
clarithromycin
dexamethasone
erythromycin
fosphenytoin
itraconazole
ketoconazole
L-asparaginase
levothyroxine
metoprolol
oxcarbazepine
paracetamol
phenobarbital
phenytoin
pimozide
primidone
rifampicin
simvastatin
warfarin

The following types of medicine may interact with Glivec:

antiepileptics
benzodiazepines
calcium channel blockers
cytochrome P450 enzyme inducers
cytochrome P450 enzyme inhibitors
HMG-CoA reductase inhibitors
statins

.

Having attended a seminar last year, a direct question to the consultant was if it was OK to take paracetamol. His answer was clear, yes it is absolutely fine to take paracetamol with Glivec.

I've taken it a few times, mainly when I have had a cold and there has been no noticeable impact.

Yes.... you are right. The proviso is not to take too much or take it regularly - as some people might do. The only issue with this kind of pain killer is that it is metabolised by the liver, as is imatinib, other TKIs and so many other drugs.

I think that we need to just be cautious if taking any drug at the same time as TKI therapy.

Best,
Sandy

Thank you for replying Sandy.

Yes, anti-histimine indeed.
I will only use Zyrtec a week or two, and as ive read somewhere, zyrtec also seems to be given when Glivec causes rashing of the skin.