I would have him stop the creatine for awhile and see if that is it. Have you looked to see if that is a possible side effect? Either way, might be a good idea to have him stop that just to see.
Creatine causes water retention which can be bad for the heart. There is rare cases also of kidney stones from taking Creatine. I would stop the Creatine before it causes any real heart damage. When blood pressure gets this high there is a higher chance of stroke.
Along with discontinuing the creatine, what kind of workouts is he doing? If he is lifting heavy weights, may want to cut back on this. Go with lighter weights, for higher reps, and remember to breathe properly when lifting. Never hold your breath when pushing heavy weight, as can increase blood pressure. Cardio workouts may be better for heart, running and such. I would definitely discontinue the creatine. After blood pressure has resolved, if he still wants to gain weight, get it from nutrition. Sounds like he is looking for muscle gains quickly. Need to have patience and gain weight properly, through good nutrition and proper rest between workouts. However, this elevated blood pressure needs to be resolved. Definitely, discontinue creatine and look at workout regimen. Hope this helps.
it would probably be rare for creatine to raise blood pressure. It does result in water retention, but that's in the muscle cells, not in the circulation. If it were causing the rise in BP, that would be a rare case.
OTOH, the creatine probably is the likely suspect. So, like everybody says, the reasonable approach is to discontinue it and see if BP goes down. That's not guaranteed, and you can't overlook the possibility of something worse, like kidney disease. Or it might be from something else he's taking. But as far as I know, creatine does not have a reputation for increasing BP.
I'd weigh him before and after discontinuing, to see how much water weight is lost. A person can have gained 10 lbs in 10 days with creatine, mostly from water.
I suffer from what is called Polycystic Kidney Disease (google it) which causes chronic kidney stones. Many people have this disease with no signs until they are much older. When their kidneys begin to fail them. The main symptom is high blood pressure beginning as a young adult. why? Because your kidneys are working too hard fighting off the cysts and they are not filtering correctly. I was diagnosed with PKD in July last year after a car accident. I just happened to decide to see a friend who happened to also be a urologist as I did not have medical insurance and knew he would let me pay it out. He ran a series of tests and came to find I had chronic kidney stones. A total of 6. Just in there. Probably been there for years. If you have high blood pressure on top of chronic stones I highly recommend you get tested. A CT scan is the best way to get diagnosed and make sure you see a Urologist who. If you would like to here more about my story I will happily tell you. Before you get tested you need to know this is a fatal disease and this will affect your ability to get life insurance and affordable health care if you do not have it prior.