Two weeks prior to an operation, patients should be instructed to stop taking NSAIDs, aspirin, anticoagulants, herbal medication, and vitamin E. Medications to be taken even on the day of operation include antihypertensive medications, diabetes mellitus (DM) medications, and thyroid hormone. Patients should be NPO for 4 h prior to IV sedation and 8 h prior to general anesthesia. Patients with high levels of anxiety can be given anxiolytic drugs prior to an operation.