If you are allergic to insulin, you should not take Lantus. Taking or having allergies to a number of other drugs may preclude you from taking Lantus due to interactions. Thyroid, kidney, or liver disease, as well as pregnancy, may also prevent you from taking Lantus. It is essential to tell your doctor all medications that you currently take, including vitamins and supplements, along with a history of your major diagnoses. You might not be able to take Lantus if you take beta-blockers, ACE inhibitors, disopyramide, fibrates, fluoxetine, MAOIs, diabetes medications, pentamidine, salicylates, antibiotics, antipsychotics, corticosteroids, danazol, diuretics, estrogen, birth control pills, isoniazid, phenothiazines, progesterones, protease inhibitors, somatropin, sympathomimetics, or thyroid hormones, as these have the potential for drug interaction.