What compounding is, and when a prescription needs it

Compounding is the preparation of a medication for one named patient, against a written prescription, when a commercially available product does not fit that patient's order. It is a normal part of pharmacy practice, and it is bounded by the prescription — nothing is prepared for stock.

The definition, narrowly

A compounded preparation is made by combining, mixing or altering ingredients to produce a medication tailored to an individual prescription. The prescriber decides that a compounded preparation is appropriate; the pharmacist prepares and releases it; both work from the same written order.

Because it is made per prescription rather than manufactured in batches for general sale, a compounded preparation is not a registered pharmaceutical product and does not go through product registration. That is a structural difference in what the two things are, not a judgement about either.

Situations that commonly call for it

The reasons a prescriber may order a compounded preparation are practical rather than exotic. Common ones include:

• A strength or concentration that is not commercially available, often for a paediatric or geriatric patient.
• A different dosage form — for example a liquid where only a solid form exists, for a patient who cannot swallow.
• The need to exclude a specific excipient, dye or preservative a patient reacts to.
• A commercial product that is on back order or has been discontinued, where an alternative is not suitable.
• A sterile preparation that must be made ready-to-administer for a particular clinical setting.

Sterile and non-sterile are different jobs

Non-sterile compounding covers preparations such as oral liquids, capsules and topicals. Sterile compounding covers preparations that must carry no viable micro-organisms — injections, infusions and ophthalmics — and is done in a controlled environment with validated technique. Sterile work carries the tighter requirements of the two, because the preparation bypasses the body's own barriers.

What compounding is not

Compounding is not a way to obtain a medication without a prescription, and it is not a route around product registration. A valid prescription is required in every case, and a pharmacy that prepares a medication on a patient's request alone is not compounding — it is dispensing without an order.

It is also not a claim of improvement. A compounded preparation is not represented as safer, stronger or more effective than a commercially available product; where a registered product fits the prescription, that product is ordinarily the one used.

This article is general educational information about compounding as a field. It is not medical advice and does not describe any individual patient's treatment. Decisions about a medication belong to the prescriber who knows the patient.