Potential side effects of Zantac, or ranitidine, include headache, constipation, diarrhea, stomach pain and nausea, according to MedlinePlus. Patients should notify a doctor of any side effects that are severe or persistent.
Common side effects of Zantac can also include breast swelling and pain, sexual side effects and additional gastrointestinal or digestive side effects such as vomiting, abdominal pain and nausea, notes WebMD.
Other potentially serious side effects of Zantac or ranitidine include jaundice (yellowing of the skin and eyes), blurry vision, mental disturbances including sudden mood changes such as depression, fatigue, irregular or abnormal heartbeat, loss of appetite, easy bleeding and bruising, dark urine and severe blistering and peeling skin. Individuals who experience any of these serious symptoms in connection with Zantac should consult their doctors, advises the NIH.
Classified as an H2 receptor blocker, Zantac works by decreasing the amount of acid produced by the stomach, states MedlinePlus. Zantac treats ulcers, gastroesophageal reflux disease and certain medical conditions that cause overproduction of stomach acid. It also prevents and treats heartburn related to acid indigestion and sour stomach. Zantac is available with or without a prescription, and is generally taken one to four times daily. It's most effective at preventing symptoms when taken 30 to 60 minutes before eating.