Is it safe to combine dramamine with DXM?

Hey, I've combined these two drugs a couple times with a problem, except that it makes me really stupid. At 300mg dxm and only 200mg dimenhydrinate, I saw Ronald McDonald come in my room and try to steal my bed. I've been wondering if a dose of 360mg dxm and 400mg dimenhydrinate would be safe, considering I have chronic insomnia and generalized anxiety disorder with episodic psychotic features.