my doctor added novolog® at mealtime for additional control. now i know. novolog® is a fast-acting, injectable insulin and it works together with my long-acting insulin. proven effective. the mealtime insulin doctors prescribe most. available in flexpen®. vo: novolog® is used to control high blood sugar in adults and children with diabetes. take novolog® as directed. eat a meal within 5 to 10 minutes after injection. check your blood sugar levels. do not take novolog® if your blood sugar is too low or you're allergic to any of its ingredients. tell your doctor about all medical conditions and medicines you take. ask your doctor about alcohol use, operating machinery, or driving. the most common side effect is low blood sugar. symptoms may include dizziness, sweating, confusion, and headache. severe low blood sugar can be life-threatening. other common side effects include low potassium in your blood and injection site reactions. get medical help right away if you experience trouble with breathing, serious allergic reactions like swelling of your face, tongue, or throat, sweating, extreme drowsiness, dizziness, or confusion.