...prescribed twice the necessary dose of antibiotics so that I spent most of yesterday throwing up and had to go to an out-of-hours clinic.
The fun didn't end there either, I was given an injection of anti-emetics and off I went, only for the doc to phone me and say that she'd injected me with the wrong drug! 
She was very apologetic and came round to administer the right dose.
I suppose I should be angry at her too but I'm not.
But what if this had been a different medicine that could have had harsher side effects?
I just clarifed with Boots - the original prescription definitely stated one tablet twice a day, not two!