June is only 2.5 months away; there's no way you can "safely" lose 40 pounds in that time frame. Even trying to lose that much in such a short time, could actually drive your blood pressure even higher.
The best approach to safe weight loss to calculate the number of calories, you need to consume each day, then drop a few hundred off, so you'll be eating less than you need. Keep a food diary so you know exactly how many calories you're taking in.
Make sure you get plenty of exercise. Recommended amount is 30 min/day, at least 3 days/week. Anything that keeps you moving and gets your heart rate up for 30 min is considered "exercise". This can be a brisk walk, bike ride, swimming, yoga. Just choose something you enjoy and go for it.
We've just started a weight loss challenge, if you'd care to join us, you can access it via the following link:
http://www.medhelp.org/posts/Weight-Loss--Dieting/SUMMER-WEIGHT-LOSS-CHALLENGE/show/2118666
Safe weight loss is considered to be 1-2 pounds/week. I've had a lot of trouble losing, so I've committed to at least 1 pound/ week. Hope you'll decide to join us. By the way, I also have high blood pressure and take med for it... there are worse things to have to take med for, than that.