Will talking leptopril and slim fast be dangerous

You didn't state how much you need to lose, you should see your family doctor before starting any diet regime. That being said, I try to caution people from using diet pills. Leptopril has ALOT of caffeine in it. Also, the makers of Leptopril have made several false claims that caused them to be investigated by the FTC (Federal Trade Commision). Here is the FTC website, with it's report.
http://www.ftc.gov/opa/2004/06/dietsupp.shtm

Here is part of a post I did recently, and it applies here as well...
As we get older, for most of us, our metabolism tends to slow down. Weight loss has to be gradual to be permanent. You are basically reprogramming your body's metabolism. You should eat several sensible, smaller meals throughout the day. Avoid carbonated and caffeinated drinks. We are all carbon-based beings, so drinking carbonated drinks reduces the calcium in your bones by binding to it, therefore making you more susceptible to osteoporosis. Reduce coffee and tea, although if you drink several caffeinated drinks a day you will want to wean yourself off or you will feel yucky and be prone to some serious migraine-type headaches. Increase your water intake. Learn to read food labels, as you will see that some "low-fat" products are higher in sodium and sugars which can defeat your purpose. Empty carbs from pastas, breads, rice, potatoes, and sugars. These will slow yor metabolism down, which is counter-productive. Increase your heart rate through some sort of extra activities. Working out does not have to be painful. Do little things like park farther frm the door at the grocery store, get up and more around more than you already do. Engage in evening walks with someone whom you like to talk to. You will actually start to feel better and have more energy than you do right now. Avoid diet pills and "quick fix" gimics, as they may increase your metabolism, but only temporarily. If you have ever known anyone who abused drugs and quit, you will notice that after 10 of being clean, they are probably at least 50 lbs overweight now. Look at Elvis before he died. That is what the long-term effects of using many diet pills can have later on in life.
Good luck in your weight loss program, Be healthy. Susu