Substitution allowed to address shortage of cefalexin

The Therapeutic Goods Administration (TGA) has been notified of shortages of multiple strengths and presentations of oral cefalexin medicines (capsules and oral suspensions). These shortages are due to manufacturing issues at a major supplier leading to unexpected increases in demand for alternative suppliers.

Cefalexin is a widely used antibiotic used to treat many different bacterial infections.

To assist with timely access for patients using cefalexin, the TGA has made a Serious Scarcity Substitution Instrument (SSSI): Therapeutic Goods (Serious Scarcity and Substitutable Medicine) (Cefalexin) Instrument 2022. This SSSI:

• declares most oral cefalexin medicines as scarce medicines
• specifies the substitute medicine as per the substitution protocol provided in the table included in the SSSI
• does not declare 250 mg capsules as scarce medicines as they are not in shortage.

While cefalexin products generally are in short supply, some have limited availability. This SSSI allows a pharmacist to provide another cefalexin medicine, when the prescribed medicine is unavailable, without prior approval from the prescriber. The pharmacist will then notify the prescriber of the substitution soon after and will include the correct instructions to the patient for the provided cefalexin product.

The SSSI allows a pharmacist to offer to the patient or their carer:

• an alternative cefalexin syrup or suspension strength when the prescribed one is unavailable
• cefalexin 250 mg capsules if the prescribed 500 mg capsules are unavailable
• cefalexin 250 mg capsules if the prescribed syrup or suspension is unavailable, the patient can swallow capsules, and the dose is divisible by 250 .

The SSSI is in force from 21 December 2022 until 31 July 2023. It may be extended if the shortage continues, or the TGA may revoke the SSSI before its end date if the serious scarcity is resolved, or safety concerns are identified. This SSSI is in effect in all states and territories.

For more information about SSSIs see Substituting scarce medicines and Serious Scarcity Substitution Instruments (SSSIs).

Information for pharmacists

The SSSI allows you to substitute the specified cefalexin products without prior approval from the prescriber, so long as the permitted circumstances provided within the SSSI are met. See both the Specific permitted circumstances (in Schedule 1) and General permitted circumstances (in Schedule 2) of the SSSI for cefalexin.

Use your professional and clinical judgement to determine whether a patient is suitable for substitution, inform the patient or their carer of the substitution, and gain their consent to the change. Some patients may not tolerate certain dosage forms and may only be able to take a liquid presentation. For those patients, if an oral solution is not available, refer them back to their prescriber to consider alternative treatment.

You can use a cefalexin medicine approved under section 19A of the Act as a substitute for a scarce medicine. More information on these products is available on the Section 19A approvals database. 

Information on Pharmaceutical Benefits Scheme (PBS) subsidy arrangements for medicines substituted using an SSSI can be found on the PBS website.

Please advise patients to contact their prescriber if cefalexin is not available from your pharmacy so they can consider an alternative antibiotic if necessary.

You can choose the best way to communicate with the prescriber about the substitution. You can use email, fax, a letter, or phone call, at the time of the substitution or as soon as practicable after the you have performed the substitution.

Many of the following actions are usual pharmacist practice but are included here for clarity as they must be followed to use the SSSI. Pharmacists should:

• Use their clinical judgement to determine if a substitution is appropriate for the patient.
• Calculate and provide the correct dose to the patient or their carer.
• Explain to the patient or their carer and confirm their understanding that:
  • A different product has been supplied due to the prescribed product being unavailable.
  • Each medicine is the same active ingredient but are different strengths.
  • If the patient takes the medicine as directed by the pharmacist, the patient will receive the same dose they were prescribed.
• For liquid preparations:
  • Calculate the correct volume required to provide the prescribed dose.
  • Include the correct dose, written in millilitres, on the dispensing label.
  • If multiple bottles are being dispensed, manage the reconstitution and supply of the bottles so that the treatment course will finish prior to the expiry of reconstituted bottles.
• For capsule presentations dispensed instead of a liquid presentation:
  • Confirm that the patient can take a capsule dosage form.
  • The prescribed dose must be divisible by 250 mg.
  • Inform the patient about the differences between the products.
• Consider how you explain to the patient or their carer the total duration of their course of cefalexin, and there may be some medicine leftover at the end of their course, so they clearly understand this information.
• Provide the patient or their carer with information to support them in administering these medicines such as the Consumer Medicine Information (CMI) leaflet, if required.

Information for prescribers

Consider the current shortage of cefalexin when prescribing for your patients but continue to follow best practice prescribing for antibiotics. Do not change your prescribing practice to second-line antibiotics without strong clinical indications for doing so.

When prescribing an oral liquid or suspension cefalexin, consider if a capsule dosage form can be prescribed instead to preserve liquids for paediatric patients and patients with swallowing difficulties.

Be alert to the potential that patients may be offered a substitute product by the pharmacist.

A pharmacist may supply a capsule presentation instead of a liquid presentation if the prescribed dose is divisible by 250 mg and they have confirmed with the patient that they are able to take capsules.

Patients will be advised to contact you if cefalexin is not available from their pharmacy. Please consider an alternative antibiotic if necessary.

Information for patients

Talk to your prescribing doctor or pharmacist if you have any questions about this substitution.

The substitute medicine contains the same active ingredient as your prescribed medicine but may be in a different dosage form or contain a different strength of the active ingredient. The pharmacist will supply the correct total dose as prescribed.

If you have been prescribed a liquid dosage form and are unable to take a capsule, advise your pharmacist.

You should take cefalexin for the number of days instructed by your doctor and pharmacist. This may result in some leftover medicine at the end of the course.

Excipients (inactive ingredients, including sweeteners, flavours, and colours) vary between brands. Let your pharmacist know if you are allergic or intolerant to certain ingredients. You can also find information about excipients, as well as other information, in the Consumer Medicine Information (CMI) leaflet, which is available from your pharmacist or on the TGA website.

Information on how the substitute cefalexin medicines are subsidised on the Pharmaceutical Benefits Scheme (PBS) can be found on the PBS website.

Keep in mind that health professionals at the medical practices and pharmacies you visit want the best possible health outcomes for everyone, but they do not control the availability of cefalexin. Please do not take any frustration or anger out on your pharmacist or doctor.

If you are unable to fill your cefalexin prescription, you should speak to your pharmacist or doctor about possible alternatives.

Medicine disruptions occur for a range of reasons and sometimes shortages cannot be prevented. The TGA continues to actively monitor the supply of important medicines and is committed to assisting you in situations where your medicine supply may be disrupted.