working with a doctor is always advisable, especially for contraindications with other medicines/supplements you may be taking. You might go to an OCD message board, for info from people who understand your condition. We focus on MS here.
Excess glutamate is one connection between the use of NAC in MS and in OCD---
I'm not a doc, but I've researched NAC as a supplement to help endothelial dysfunction, or vasoconstriction, found in cardiovascular and cerebrovascular disease. It shouldn't cause hypertension, since NAC relaxes vessels, and enhances nitric oxide distribution--http://www.ncbi.nlm.nih.gov/pubmed/21713097
It's a wonderful antioxidant, and decreases inflammation. It's also helpful dealing with abnormal glutamate levels in OCD-http://www.ocfoundation.org/glutamate.aspx
That said, you are taking a high dosage. The highest dosage I've seen used in clinical trials in 2000 mg. (1000 mg. twice a day) Please be careful. More is not always better,