3 Clinical psychopharmacology3.1 General pharmacology
3.1.6 Drug regulation and licensing
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Written by Resident Doctor Committee · Published
Marketing authorisation
A UK marketing authorisation means a product has acceptable quality, safety and efficacy for specified uses. It does not prove superiority or remove harm.
The Summary of Product Characteristics (SmPC) sets out a product's authorised uses, doses, route, contraindications, interactions and monitoring.
Licensed, off-label and unlicensed use
Pregabalin holds a UK licence for generalised anxiety disorder, neuropathic pain and adjunctive treatment of focal seizures, so prescribing it for insomnia is off-label.
Gabapentin, its relative, has no UK licence for generalised anxiety disorder.
Feature | Off-label use | Unlicensed medicine |
|---|---|---|
Definition | A licensed product used outside its authorised terms | A product with no UK authorisation |
Example | Use outside the authorised age range | A special, imported or extemporaneous product |
Off-label use can be evidence-based, but the prescriber must justify it, consider licensed alternatives and document the reasoning.
Lithium formulations
Lithium carbonate comes as tablets and lithium citrate as an oral liquid.
The two salts carry different amounts of lithium per milligram, so a switch is calculated by lithium content, not milligrams.
Lithium citrate 520 mg in 5 mL supplies about 5.4 mmol of lithium, the same as lithium carbonate 200 mg, so 400 mg of carbonate equals 10 mL of that liquid.
Lithium has a narrow therapeutic index, so clinicians prescribe it by brand and monitor any switch.
Pharmacovigilance
Yellow Card reports of suspected adverse reactions should be made without waiting for certainty.
Black triangle medicines need every suspected adverse reaction reported.