It is your responsibility to establish the medication rules for the destination, airline and any country you are travelling through.
You need to remember about prescribed and over-the-counter-medication.
A letter may be required for travelling with medication. This is not an NHS service. Your GP may be able to issue you with a letter; however there will be a charge for this.
If you are going abroad for more than 3 months, your GP will prescribe sufficient medication to allow you to obtain an alternative supply abroad.
GPs are not responsible for prescribing ‘just in case’ items for conditions which may arise when you are abroad.