For cardiology, over 60% of drugs are used in an “off-label” situation. It’s estimated that only 6% of the time do guidelines exist for how to use those drugs off-label. Instead, the doctors use their judgement.
“From the FDA perspective, once the FDA approves a drug, healthcare providers generally may prescribe the drug for an unapproved use when they judge that it is medically appropriate for their patient.
You may be asking yourself why your healthcare provider would want to prescribe a drug to treat a disease or medical condition that the drug is not approved for. One reason is that there might not be an approved drug to treat your disease or medical condition. Another is that you may have tried all approved treatments without seeing any benefits. In situations like these, you and your healthcare provider may talk about using an approved drug for an unapproved use to treat your disease or medical condition.”
Read the full article at the FDA website: Understanding Unapproved Use of Approved Drugs “Off Label”