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Arrow-Fluoxetine has been available, fully subsidised on the Pharmaceutical Schedule since 1 February 2014. From 1 April 2014, subsidy for the Fluox brand of fluoxetine decreased, therefore many patients will have switched brands already. Subsidy will be fully removed from Fluox from 1 July 2014, leaving Arrow-Fluoxetine as the only subsidised brand of fluoxetine.

Fluox has been the subsidised brand of fluoxetine in New Zealand for the past ten years, so for most patients, this will have been the only brand they have used. A brand change may be unnoticed by some patients, but may cause some anxiety for others, and these patients are likely to require extra support with the change.

Table 1: Arrow-Fluoxetine compared with Fluox

Arrow-Fluoxetine Fluox

Physical appearance

Capsule: size 2, hard gelatine, green/off-white capsules, imprinted with ‘FLX’ and ‘MIL’ in black ink.

cap2.jpg

Capsule: size 3, hard gelatine, light green/purple capsules, imprinted with ‘FL20’ and ‘α’ in black ink.

cap1.jpg

Dispersible tablet: white, round tablet, 10.5 mm, with a break-line on one side

tab_1.jpg

Dispersible tablet: white, oval tablet, 12.6 mm x 6 mm, with a break-line on one side and debossed with ‘FL’, ‘20’ and ‘G’.

tab_2.jpg

Excipients

Capsule: gelatin, maize starch, yellow iron oxide, titanium dioxide.

Dispersible tablet: cellulose, croscarmellose sodium, colloidal anhydrous silica, magnesium stearate

Capsule: maize starch, lactose monohydrate, colloidal anhydrous silica, purified talc, magnesium stearate

Dispersible tablet: cellulose, colloidal anhydrous silica, magnesium stearate, maize starch, crospovidone, saccharin, peppermint powder

What can the patient expect with a brand change?

Brief counselling at the time of the brand change can significantly increase the patient’s acceptance of the change. Reassure the patient that they will be receiving the same amount/strength of their medicine, and they should not notice any difference in their treatment.

It can be helpful to explain to patients what their new medicine will look like. Table 1 compares the physical attributes of Arrow-Fluoxetine with Fluox. Arrow-Fluoxetine, as with Fluox, is available in blister packed 20 mg capsules and 20 mg dispersible tablets, which can be halved.

If patients require further help with the brand change, they can contact the PHARMAC helpline (0800 66 00 50 – 9am to 4pm weekdays) or email: enquiry@pharmac.govt.nz

Patient information brochures about the fluoxetine brand change can be ordered from: www.pharmaconline.co.nz

What can the clinician expect with a brand change?

In general, brand changes are often followed by an increase in the number of reports to the Centre for Adverse Reactions Monitoring (CARM). Typically, these reports describe a loss of therapeutic effect compared to the original brand of medicine. Other frequently reported adverse effects after any brand change include: nausea, vomiting, diarrhoea, rash, pruritis, headache and dizziness. The general pattern is an initial peak of reports, then a decline, even though the new medicine continues to be available, suggesting that these adverse effects are attributable to the change process rather than the medicine itself.

Medsafe has approved Fluox and Arrow-Fluoxetine as being bioequivalent to the innovator brand, Prozac, based on internationally accepted criteria and standards for calculating bioequivalence. This means that most patients should expect to experience the same clinical effect and adverse effect profile from either brand.

Patients changing from Fluox to Arrow-Fluoxetine should be prescribed their usual dose and regimen. In a small number of cases, dose adjustments may be required if the patient reports a lack of therapeutic effect or adverse effects. The Arrow-Fluoxetine datasheet states that: “Arrow-Fluoxetine Dispersible may not be interchangeable with similar products on the New Zealand market”, which means that closer monitoring of dose may be needed for patients taking the dispersible formulation (for which funding is restricted to patients who cannot swallow tablets or who need doses that are not multiples of 20 mg).

Patients should be followed-up after they have changed brands to ensure that it has not affected their adherence to their medicine regimen.

If a patient does not respond well to the brand change, consider adjusting the dose or trialling a different SSRI or a different type of antidepressant.

For further information on changing antidepressants, refer to the Antidepressant Switching Table in Chapter 4.3 ‘Antidepressant drugs’ in the New Zealand Formulary or the “Guide to managing depression in adults”, BPJ Special Edition (2009).

For further information on generic medicines, brand change and bioequivalence, see: “Generics”, BPJ Special Edition (2007).

Best Practice Prescribing tips

  • Prescribe using the generic name of the medicine (there are some exceptions to this, e.g. warfarin)
  • Ensure the patient knows the generic name of the medicine they are prescribed and try to refer to medicines by their generic name rather than brand names
  • Ensure the patient understands how to take the medicine, their prescribed dose, and why they are prescribed the medicine