The antacid medication Zantac, also known by its generic name ranitidine, is associated with several side effects, including headache, dizziness, constipation and diarrhea; these tend to be the most common and least severe side effects from this medication, according to the National Institutes of Health (NIH). Although these are common side effects, those who experience them persistently are advised by organizations such as the NIH to consult their doctors. Both prescription and over-the-counter versions of Zantac or generic ranitidine are available for consumers in the United States, and the side effects list is the same for both versions of the drug.
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.