Topamax can be a wonder drug for some people and absolute poison to others. For me it was POISON. I had horrible side effects, I became practically brain damaged. I've been off the medication for over two years, and I still have not regained the mental abilities I had before taking the medication. The side effects can very widely, and can depend on dosage and how fast dosage changes are made. This medication needs to be very slowly "titrated" or changed up or down in dosage. Changing too fast can make the side effects even worse.
Usually a patient's doctor's records contain an emergency contact, which allows the doctor to share medical information with this contact person. I'm sure your husband must have you listed there. This should allow you to talk with his doctor directly, and I would do some as soon as humanly possible.
When you talk with his doctor and inform him of your husband's behavior problems, it could be that his dosage is not correct. If it is helping his migraines, perhaps he can add a medication to counteract his behavior problems. I've never heard of agression being one of the side effects, but there are so many, anything is possiblen.
Please let us know how things go.
I just stopped taking Topamax yesterday and will never take it again. It actually was giving me headaches, making me extremely dizzy, I felt unsteady on my feet. Those symptoms just brought on panic attacks. Dr originally prescribed 50 mg and after 1 day I thought I was having a seizure - he told me to take 1/2 (25mg) which I did for 2 weeks - I haven't felt that bad in a long time. Today I felt fine with no Topamax.
I have heard of people who do well on this and have no side effects, but anger & agression is one of the side effects that I read. I would definitely have him talk to his Dr about this.