How to check for interactions

[Asterix]

Just wondering as part of some learning for next year, how would you go about checking an interaction between 2 items on an rx.

For example,

Diclofenac MR tablets 100mg and Cytotec tablets 200mcg, how would I go about checking these with bnf and making sure they are safe?

[laurabuk]

Giggsy,

Are you sure thats an interaction? I would advise you look up page 539 of BNF 55

[johnep]

Combination available as Arthrotec.
johnep

[SolomonQ]

I think people got the wrong end of the stick with this one,

What giggsy is asking is if he wanted to check interaction between two drugs how would he do it.

All interactions are in appendix 1 of BNF. all meds are listed in alphabetical order, you just look for one of the drugs, sometimes listed under drug class rather than drug name e.g. ibuprofen and diclofenac both under NSAIDs.

black dot interactions are the serious ones, the other ones need to be managed in some way, could be serious for some. under each drug monograph in the BNF, under the cautions part tells you what to look for in appendix 1.

[Asterix]

yeah that's exactly what I was after solomon

[laurabuk]

What I was suggesting - and what john stated - was that these two drugs are available in a compound preparation [arthrotec], cannot be a significant pharmacological interaction if they are compounded together.

However, this scenario came up in one of our dispensing classes. Given together, these drugs do not interact but the key thing to remember giggsy is that interactions don't necessarily have to be with other drugs - but with a patients state - i.e. liver dysfunction, renal dysfunction or reproductive state. Try appendix 4 for more information on these drugs in a certain age range.



Bit cryptic lol! But this is how our TP's are with us!!

[Steve G]

BNF is useful for brief information such as whether there is an interaction or not, but Stockley is far more useful for the actual details and management. PMR programmes can also provide information on interactions, but the quality and usefulness of the information is variable - I don't need to be told that adding an ACEI to a diuretic causes and enhanced hypotensive effect.

You will also get to know which drugs have lots of interactions and which have a few with time.

[Pharmanaut]

BNF is useful for brief information such as whether there is an interaction or not, but Stockley is far more useful for the actual details and management. PMR programmes can also provide information on interactions, but the quality and usefulness of the information is variable - I don't need to be told that adding an ACEI to a diuretic causes and enhanced hypotensive effect.

You will also get to know which drugs have lots of interactions and which have a few with time.

CegedimRx Pharmacy Manager uses information sourced under licence directly from the Pharmaceutical Press. I know that they used to deal with Ivan Stockley himself prior to the handover to Karen Baxter.

The big issue is how do you decide what to 'message'?

There is no right answer, as all of our prescribers, patients and ourselves are different. Most interactions it seems can be catered for by balancing the patients known disease states and concurrent medication by additional monitoring when adding or withdrawing a drug from their regimen. Sometimes this can be too fine a balance, and in the community setting concurrent use is not recommended.

So what I'm getting at is that as a pharmacist you need to look at the interaction, look at the patients history (on the PMR), talk to the patient - sometimes their disease state is refractory to other treatment, find out if they take any OTC or herbals. More often than not the query resolves there and then. If you are a student or pre-reg, watch your mentor handle this - if it is done right the patient will not be alarmed. Its also good PR for pharmacy If you cant make any sense of things, you can contact the prescriber for clarification. On Cegedim's Pharmacy Manager, you can record an Interaction Intervention.

As an aside, looking at the patients PMR, even a quick review as you dispense, can also turn up interesting information. For example you can confirm by asking her that Mrs Jones is expecting Enalapril 5mg Tablets, when in the past she has had Enalapril 2.5mg Tablets, and that she has been taken off Nifedipine as it is on recent PMR but not on script. Just simple examples for you. Fill in more complex ones as you get experience.

Finally, that's a long post from me.
Wonder if I can claim out of pocket expenses on it. <g>

[Asterix]

so using the bnf how would I check for an interaction between cytotec and diclofenac?

[JonF]

Solly explains how in post 4 above!

You can also go to Digital BNF, once you have registered(free) you can search interactions using the search box on top right of screen.