Hello, I'm Dr. Deb.
I recently came online and see that your question hasn't been answered. I'm so sorry that you've had to wait for a response, but if you still need assistance, I'd like to help if I can.
The short answer is that, yes, there are drugs which can be used in these situations but most of them would need to be dispensed or prescribed by your vet. Even practitioner has their own preference, of course, but I like Prozac for aggression issues. Most cats tolerate the drug very well, it can be compounded by a special pharmacy into a flavored liquid, treat or gel which you rub in the ears
and side effects are usually minimal.
Other options to consider which may or may not be helpful (but would be worth trying) would include:
1. Feliway diffuser or spray; these are natural pheromones which can help instill a sense of calm and reduce anxiety.
2. There is also an oral product called Composure Chews which is formulated to do the same thing...to calm the cat.
I hope this helps although, again, my apologies for the delayed reply. Deb