Don't worry, This isn't going to kill you. Since I'm not a medical doctor, perhaps you've taken away too much acid from your stomach. To be safe, call the medical (Poison) Hotline and explain what you did and may have to do to counteract this. If you are taking this medication for self-treatment, it is important to read the manufacturer's package instructions carefully so you know when to consult your doctor or pharmacist. How to use Pepcid My boyfriend had real bad heartburn and took maximum strength Pepcid Ac and got hives all over his chest, arms ,and neck. The hives got worse and we're itching and he's had it for 3 days now. He should not have to go through this. We are very upset and not satisfied what so ever. Do NOT give pepcid ac to your pup for this. You have NO idea why her tummy is doing this. If you don't know what the problem is you will probably make it worse diagnosing it yourself. How to use Pepcid AC. Take this medication by mouth with or without food as directed by your doctor, usually once or twice daily. If you are taking this medication once daily, it is usually taken. If you believe you may have overdosed on famotidine, seek medical attention immediately. Famotidine ( Pepcid ® , Pepcid AC ® , and Pepcid Complete ® ) is a medication that has been licensed to treat several conditions affecting the esophagus, stomach, and intestines. Pepcid is used to treat ulcers in the stomach and for conditions where the stomach produces too much acid. Learn about side effects, interactions and indications. sounds like you may have ulcers or gastritus, see a dr asap. i get ulcers and they hurt so bad or sometimes i get the inflammation of gastritus. either way i cope by taking a lot of mylanta. when i get bad ulces i take a pepcid before every meal at least 25 mins before and i take a zantac 150 every am and every pm before bed. i had to do that. Pepcid AC is used to treat and prevent ulcers in the stomach and intestines. It also treats conditions in which the stomach produces too much acid, such as Zollinger-Ellison syndrome. Doctors give trusted answers on uses, effects, side-effects, and cautions: Dr. Ilozue on is pepcid ac bad for you: Yes, Prilosec otc is stronger but gerd can be due to diseases that impair esophageal function, cause inadequate saliva, gastric outlet narrowing, gastroparesis, small bowel pathology, etc. Damage from inadequate treatment may.