Off-label drugs are drugs that are prescribed for a different condition or in a different way than is stated in their marketing authorization. For example, a drug that is licensed to treat high blood pressure may be prescribed off-label to treat migraines.
Unlicensed drugs are drugs that do not have a marketing authorization in the UK. This means that they have not been assessed by the Medicines and Healthcare products Regulatory Agency (MHRA) for safety and efficacy.
Examples:
Off-label drug: The drug sildenafil (Viagra) is licensed in the UK to treat erectile dysfunction. However, it is also commonly prescribed off-label to treat pulmonary arterial hypertension (PAH).
Unlicensed drug: The drug cannabidiol (CBD) is an unlicensed drug in the UK. However, it is available on prescription for certain medical conditions, such as severe childhood epilepsy.
Similarities:
Both off-label and unlicensed drugs may be used to treat conditions for which there is no licensed treatment available.
Both types of drugs may be prescribed by doctors, but they are not routinely available on the NHS.
Both types of drugs may have risks and side effects, even if they have been extensively tested for other conditions.
Differences:
Off-label drugs have been assessed by the MHRA for safety and efficacy, but they have not been licensed for the specific condition or use for which they are being prescribed.
Unlicensed drugs have not been assessed by the MHRA for safety and efficacy.
Off-label drugs are more widely used than unlicensed drugs.