On-call scenario 5: Resolution

Last updated: Thursday, June 06, 2024

What an on-call pharmacist could advise... 

You advise that an appropriate dose of a carbamazepine suppository for the patient who was taking 400mg MR BD would be 250mg QDS

You explain to the doctor that it is not ideal to switch carbamazepine brands/formulations, but on balance it is preferable to switch routes as the patient is unable to take any medicine orally. You are reassured that the patient is on a neurology ward, and they will be monitored closely for any change in their seizure control.

In addition, whilst researching this question, you also note that suppositories are not recommended to be used for longer than 7 days due to the risk of rectal irritation. The reason for this is that clinical trials were only conducted for this length of time. You flag this to the doctor who advises that the patient is due to have a nasogastric tube inserted in the next day or 2 and so this should not be an issue. 

Remember not just to answer the question you have been asked – always be thinking whether there are any other clinical considerations. In this case, it is imperative that you think about the patient’s other medicines too. In addition to carbamazepine, they are also prescribed pramipexole 88 micrograms ON.

It would be helpful to know the indication: in this scenario it is for restless leg syndrome. Knowing this means that you can assess how clinically urgent it is for the patient to have this medicine. The medical team may decide that the patient can go without pramipexole for a few days whilst they are NBM if it is being used for restless legs. If it were being used for Parkinson’s disease, then this is more urgent and you will have to find a solution quickly. 

Follow up 

The next morning you should speak to the pharmacist looking after this patient and inform them of the switch to carbamazepine suppositories and also any advice you gave about pramipexole.