Don't take any medicine that will do that. All medications have side affects and are really toxic. It can cause other problems. Just learn to ficus on other things.
Well even if It is a thought/mind thing isn't there something that would prevent arousal not matter what was occuring.
Off the top of my head I cannot think of anything that would gross me out enough to prevent me from having sexual thoughts or being aroused.
Try to fill your mind with thoughts that GROSS you out and turn you OFF. Like toenail fungas. Just whatever totally makes you cringe and puts the thoughts out of your mind.
Look up online about aversion therapy.
Your sex drive is a natural and normal thing. Some people have more, some people have less. Do you find yourself thinking about sex/stimulation all the time? If so, its not an arousal problems, its a mind/thought problem.
Cold shower, anyone?