Is it safe for me to take 2 ranitidine pills about 6 hours apart? The first pill didn't seen to do to much for my extreme heartburn

Follow instructions. When taking prescription medication it is important to follow the instructions instructions exactly as written. Heartburn medications can be tricky. Tums, rolaids, maalox are good at neutralizing acid at the time that symptoms are present. Ranitidine, nexium, (esomeprazole) omeprazole, Pepcid are good at preventing stomach acid. These should be taken daily to prevent the symptoms from coming up.