The Three W’s of Compounded Medicines – for Vets

Original Article | Do you know the three Ws of compound medicine? | Medical Council of New South Wales (mcnsw.org.au)

In recent years there has been an increase in complaints about compounded medicines supplied by community pharmacies. These complaints relate to three W’s – who is making it, where (and in what conditions) is it being made and what exactly is in the compound medicine? 

Most complaints about compounded medicine in NSW are handled by the Pharmacy Council, but in some cases veterinary practitioners are involved, which is when the complaint can be referred to the Veterinary Board. 

Regulation of medicines in Australia

All medicines supplied in Australia for human use must be included in the Australian Register of Therapeutic Goods (ARTG). All medicines for animal use must be registered by the Australian Pesticides and Veterinary Medicine Authority (APVMA). This ensures that medicines meet certain standards to ensure the health and safety of patients. All medicines that are listed on the ARTG, such as vitamins and complementary medicines, are tested against standards for quality and safety. Medicines that are registered on the ARTG or PubCRIS, such as prescription-only medicines, are also tested for efficacy. These medicines must be manufactured in a licensed or approved facility which is overseen by the Therapeutic Goods Administration (TGA) in accordance with the Therapeutic Goods Act 1989 (the Act) and Therapeutic Goods Regulations 1990 (the Regulations).

The Act and Regulations allow for certain exemptions in specific circumstances to permit:

  • the manufacture of medicine without holding a manufacturing license
  • the supply of a product not included in the ARTG.

Under this exemption, pharmacists can manufacture or compound medicine that is not included in the ARTG without a manufacturing license as long as it is for supply to a specific named person for therapeutic application to that person or animal only.

The circumstances whereby compounding is permitted is limited to when:

  • an appropriate commercial product is not available,
  • a commercial product is not suitable (e.g. if a patient is allergic to an excipient in the commercial product), or
  • undertaking research sanctioned by a recognised research ethics committee.

How are medicines compounded by pharmacists regulated?

Unlike medicines on the ARTG, medicines compounded in community pharmacies are not assessed by any agency for quality and safety or efficacy. The ingredients of the compounded products may have been sourced from anywhere in the world. There is no TGA oversight of the inspection or testing to ensure the ingredients are what the supplier says they are or that the ingredients are safe or fit for human or veterinary use!

Veterinary practitioners and pharmacists have individual responsibilities when a compounded medicine is prescribed, compounded and dispensed to ensure the patient

  • has been provided with information about the medicine which has been prescribed for compounding, and
  • understands that unlike medicines on the ARTG and PubCRIS, compounded medicines have not been assessed by the TGA or APVMA for efficacy, quality and safety.

When should you be prescribing compounding medicines?

Veterinarians should only be prescribing a compounded medicine under very specific circumstances when:

  • an appropriate APVMA registered product is unavailable, or
  • an appropriate ARTG registered product is unavailable, or
  • a commercial product is unsuitable.

If a compounded medicine is considered, good practice indicates that the veterinary practitioner and pharmacist should identify:

  • whether the substance(s) in the compounded medicine is suitable and approved for veterinary use,
  • whether there is sufficient evidence to support the intended use based on recognised therapeutic standards,
  • whether the medicine will remain stable for the duration of use, and
  • the possibility of contamination of the medicine and the level of risk that contamination would present. For example, the risk of contamination of eye drops that should be sterile.

When considering the provision of a compounded product for a patient, the patient is permitted to nominate a pharmacy. “Channelling” of prescriptions to a particular pharmacy by a prescriber is not permitted.

Case study

A recent investigation conducted by the NSW Pharmaceutical Regulatory Unit (PRU) highlights some of the issues when considering prescribing medicine that requires compounding.

Phentermine is an appetite suppressant, and available commercially in Australia as the ARTG registered products Duromine® and Metermine®. Both products are presented as 15mg, 30mg or 40mg modified-release capsules. As there is a commercially available product there should be no need to prescribe compounded phentermine except, perhaps, when the patient is lactose intolerant (lactose is an ingredient in the commercially available product).

A recent complaint identified a large number of prescriptions written for phentermine and supplied by one compounding pharmacy for:

  • Phentermine capsules in differing strengths of 50mg, 60mg and 80mg, and
  • Phentermine in combination with additives such as chromium, 5-hydroxytryptophan, or topiramate, and
  • These products were compounded in a formulation where modified release properties were untested and uncertain.

Following an investigation, the PRU identified these issues:

  • The need for additional strengths of phentermine over and above the recognised therapeutic standard dosages was not well supported or adequately justified.
  • The combinations prescribed were based on very limited data.
  • Duromine and Metermine both contain an ion-exchange resin complex which provides for controlled release over a 10 to 14-hour period. The effects of a compounded formulation on the pharmacokinetics and pharmacodynamics of the drug in a patient are untested and unknown.

It appeared that the medical practitioners were prescribing ‘compounded’ phentermine as a default rather than as an exception. They claimed that the cost of the ARTG registered products was prohibitive for many patients, and the compounded product was being prepared as a cheaper alternative. The prescriber had ‘channelled’ the patient to a specific pharmacy.

The Medical and Pharmacy Boards of Australia consider that the health and wellbeing of patients is the priority and that it is in the best interests of the patient that medications which are prescribed and supplied be subject to the stringent criteria required by the TGA. They consider that prescribing compounded formulations by default means that the circumstances of each patient are not being considered. Compounding should only be considered if and only when an ARTG product is not suitable or available.

During the investigation, one medical practitioner who was interviewed stated that the compounding pharmacy had shown her that their compounded version of phentermine exhibited ‘a better side effect profile than that of the Duromine® capsules’ and that she had been shown dissolution, disintegration and pharmacodynamic data of the compounded product.

However,

  • For such data to be relied upon, tests need to have been performed on the actual compounded product.
  • The pharmacist involved stated the tests performed were crude dissolution tests and admitted that the tests had no sound scientific data.
  • The medical practitioner conceded this data had never been provided to her.
  • A risk/benefit assessment for the compounded product and individual patients had not been undertaken by the prescriber or the pharmacist
  • Patients were not informed that the compounded medicines were not tested or assessed by the TGA for efficacy, quality and safety. As such, patients were not allowed to make an informed decision about their treatment.

In this case, both the medical practitioners and pharmacists involved were referred to the relevant Councils where immediate action under section 150 of the National Law was taken. Restrictions on their ability to prescribe and compound certain medicines were imposed, with the matters ongoing.

What are my obligations:

Veterinarians and pharmacists are reminded:

  • that the prescribing and dispensing of compounded medicines should only occur in circumstances where:
    • there a no other APVMA or TGA medicines which would provide a similar therapeutic outcome, or
    • a registered medicine is not suitable
  • that they have individual legal and professional responsibilities when a compounded medicine is prescribed, compounded and supplied,
  • to be aware of the need to ensure a prescribed compounded medicine is assessed for risk and evidence-base to ensure the health and safety of the patient.
  • to support patients in making an informed decision about their treatment by ensuring that they:
    • understand that unlike APVMA medicines on medicines on the ARTG, compounded medicines have not been assessed by the TGA or any other agency for efficacy, quality and safety.
    • have been provided with information about the medicine which has been prescribed for compounding.

How VetRx can assist you to prescribe safely:

VetRx is the only resource in Australia that has compiled all TGA and APVMA medicines into one database. When prescribing, vets can work down the cascade (APVMA -> TGA -> Compounded) to ensure that the most appropriate medicine is supplied to the patient.

If the desired medicine does not exist in the APVMA or TGA database, then you rest assured knowing that it is appropriate to prescribe a compounded medicine.