Possible side effects associated with over-the-counter lansoprazole include nausea, stomach pain, diarrhea and constipation, according to Drugs.com. Headache and dizziness are also common side effects of lansoprazole. Other side effects associated with lansoprazole include skin rash or itching, fluctuations in appetite and joint pain.
Lansoprazole can also produce side effects that resemble the flu or a cold, increased cough, anxiety and muscle pain, notes Drugs.com. Lansoprazole may cause unusual bleeding or bruising, rectal bleeding or mental depression. Some people may experience coldness, burning, blistering or discoloration of the skin after taking lansoprazole.
Lansoprazole can also cause mild vomiting or diarrhea, states Drugs.com. It may result in sweating, a tingling feeling, belching, and an unusual or unpleasant taste in the mouth. Some people who take lansoprazole may notice dribbling during urination, and urination volume and frequency may diminish. Some people may have difficulty speaking due to lansoprazole.
Lansoprazole can also cause pinpoint red spots on the skin or red skin lesions that frequently have a purple center, according to Drugs.com. Other possible side effects associated with lansoprazole include pain in the lower back or side, seizures and tightness in the chest. Other unlisted side effects are possible when taking lansoprazole. Although not all side effects require medical treatment, it is important to check with a doctor if they occur to be safe.