Because what is voltaren prescribed for a topical medicine, you apply it right at the site of pain. Tell your healthcare provider: if you have a history of ulcers or bleeding in the stomach or intestines, or kidney or liver problems, or heart failure about all of your medical conditions about all of the medicines you take. Possible serious side effects include lifethreatening skin and allergic reactions. Get emergency help right away if you have any of the following symptoms: shortness of breath or trouble breathing, chest pain, weakness in one side of your body, slurred speech, or swelling of the face or throat.