Indication

Indication — or therapeutic indication — is the specific medical condition or clinical circumstance a regulatory authority has determined a drug is safe and effective enough to treat. It is the product of a formal review: the drug's sponsor submits clinical trial evidence, and the regulator assesses whether the benefit-to-risk profile justifies approval for that use.

An approved indication defines the language on a drug's official label and is the legal basis for its authorized marketing. A drug may carry one indication or several, each acquired through a separate review process. Prescribing a drug outside its approved indications — legal in most countries — is known as off-label use.

How it works · its role

To receive an indication, a sponsor typically runs phase I–III clinical trials demonstrating efficacy and an acceptable safety profile in the target population. If the regulator is satisfied, it approves the indication with precise language: the condition, sometimes a specific patient subgroup, and often the line of treatment — for instance, first-line, treatment-resistant, or adjunct to another therapy.

Indications are jurisdiction-specific. A drug approved for depression in the United States may carry no such indication in the European Union, or may hold it under different restrictions. Approval for one condition does not imply efficacy — or regulatory review — for another. Expanded indications require a separate evidence submission and a fresh review.

Relevance to substances & effects

Many substances on these pages carry approved indications. Stimulants such as amphetamine and methylphenidate are indicated for ADHD and narcolepsy; opioids carry indications for pain management, and buprenorphine specifically for opioid use disorder; benzodiazepines are indicated for anxiety disorders and seizure management; ketamine and its derivative esketamine hold indications for treatment-resistant depression.

Others are studied for indications not yet formally approved. Psilocybin and MDMA have entered late-phase clinical trials — for treatment-resistant depression and post-traumatic stress disorder respectively — with regulatory outcomes still pending or partial in most jurisdictions. A substance without an approved indication is not necessarily ineffective; it may be unapproved for historical, commercial, or scheduling reasons rather than scientific ones.

An approved indication is not a blanket endorsement. It reflects one regulator's finding, in one jurisdiction, for one defined patient population, based on the evidence submitted at that time. The indication tells you what a drug was formally studied and cleared for — not the full range of conditions it is used for, prescribed for off-label, or investigated in ongoing research.