nervous aggression

Question
I have an eleven month old German Shepherd dog. In the house he is very well behaved but outside shows signs of nervous aggression, such as pulling forward, barking and peeing, this is usually at people. We are going to training classes and he no longer barks and enjoys this but if when taking him for a walk a stranger talks to me he gets quite aggressive. My problem is that although i can stop him being aggressive, next week he is going to the kennels as i have to go away for a few days and i am worried he may try to bite one of his carers, is there any sort of mild sedative he can be given to help this ?

Answer
Though sedatives exist for cats and dogs they do have a potentially dangerous effect in relation to biting.  While a somewhat trained dog may snap at a stranger and cause a mild bite wound, sedatives can removed their bite inhibition such that as if they do grasp the person the bites they inflict can be much worse.  I would therefore not recommend using them in this case, instead alerting the workers at the kennel of her aggression so that they can be cautious.

Apologies for this delayed response.  I was unexpectedly unavailable due to a family emergency.