Compounded medicines: when pharmacists make medicines to order

Most medicines are mass-produced in factories, with identical tablets, capsules, and vials shipped to pharmacies in the millions. But sometimes a patient needs something that does not exist on a shelf — a liquid version of a tablet, a medicine without a certain dye or preservative, or a dose strength that no manufacturer produces. In these situations, a pharmacist can prepare a customised medicine from raw ingredients. This practice is called compounding, and it occupies a distinct place in the medicines supply chain — somewhere between manufacturing and routine pharmacy dispensing.

What compounding means

Compounding is the preparation, mixing, assembling, packaging, and labelling of a medicine based on a prescription from a licensed prescriber, for an identified individual patient. The pharmacist starts with active pharmaceutical ingredients and excipients — the inactive substances that carry the drug — and combines them into a finished dosage form such as a capsule, oral liquid, cream, or suppository.

This is fundamentally different from dispensing a commercially manufactured medicine. When a pharmacist dispenses a factory-made product, that medicine has been through a formal registration process: it has been tested for quality, stability, and bioavailability, and each batch is released under Good Manufacturing Practice (GMP). A compounded medicine, by contrast, is made for one patient and does not go through the same batch-by-batch quality testing or regulatory approval. The pharmacist assumes direct responsibility for the preparation's quality and suitability.

When compounding is used

Compounding is generally used when a commercially available medicine cannot meet a patient's needs. Common scenarios include preparing a liquid formulation for a patient who cannot swallow tablets — often a child or an elderly person — removing an ingredient such as lactose, gluten, or a particular dye to which a patient is allergic, or producing a strength that is not commercially manufactured. Compounding may also be used to flavour a medicine to improve adherence in children, or to prepare a medicine in short supply when no registered alternative is available.

In some cases, compounding is used to combine more than one active ingredient into a single dosage form, particularly in topical preparations. However, regulators generally discourage compounding copies of commercially available medicines simply to offer a lower price, since compounded products do not carry the same quality assurances as registered ones. In South Africa, pharmacy practice standards issued by the South African Pharmacy Council set out the circumstances under which pharmacists may compound and the standards they must follow.

How regulation differs from mass manufacturing

The regulatory divide between compounding and manufacturing is important. Mass-manufactured medicines must be registered with a medicines regulatory authority — such as SAHPRA in South Africa, the FDA in the United States, or the EMA in Europe — and produced in licensed facilities under GMP. Every batch is tested for identity, purity, potency, and dissolution before release, and the manufacturer must maintain extensive documentation to prove consistent quality.

Compounding, by contrast, is typically regulated as a pharmacy practice activity rather than as manufacturing. Pharmacists are licensed by their professional council, and compounding standards are set through pharmacy practice guidelines rather than the full medicines registration framework. Compounded medicines therefore do not carry a registration number, are not subject to batch release testing, and do not appear in formal medicines registers. The line between compounding and manufacturing can become blurred when pharmacies produce large quantities of compounded products without patient-specific prescriptions. Several regulators have introduced separate categories — such as the outsourcing facility in the United States — to bring larger-scale compounding under stricter, manufacturer-like oversight.

Quality and safety considerations

Because compounded medicines are not subject to the same testing and registration requirements as manufactured products, their quality depends heavily on the individual pharmacist's skill, the quality of the raw ingredients, and the cleanliness of the preparation environment. Errors in calculation, cross-contamination, inadequate mixing, or poor storage can all affect the final product. Stability is also a concern: while manufacturers conduct long-term stability studies to set expiry dates, compounded medicines generally have shorter, estimated beyond-use dates based on general guidance rather than product-specific data.

Serious safety incidents have highlighted the risks. The 2012 fungal meningitis outbreak in the United States, linked to contaminated steroid injections prepared by a compounding pharmacy, resulted in dozens of deaths and led to significant regulatory reform. Such events underscore why regulators distinguish between individual-patient compounding and larger-scale production. Patients searching for a specific medicine on HealthSA should note that compounded preparations will not appear in registration or pricing searches, as they are not registered products with a Single Exit Price. If a compounded medicine has been prescribed, the pharmacist who prepared it is the best source of information about its ingredients, stability, and storage.