From 1 March 2012, sumatriptan fast-disintegrating tablets (Imigran FDT) 50 mg and other brands of sumatriptan 50 mg tablets listed on the Pharmaceutical Benefits Scheme (PBS) may be substituted for each other by pharmacists, unless indicated otherwise by the prescriber.
The Pharmaceutical Benefits Advisory Committee recommended for a note to be added to the listing of sumatriptan tablets 50 mg (all current brands) and sumatriptan fast-disintegrating tablet 50 mg, stating that they are equivalent for the purpose of substitution.
The usual indicator of brand equivalence in the Schedule is an ‘a’ next to the brand name. However, in this case sumatriptan fast-disintegrating tablets 50 mg and sumatriptan 50 mg tablets have different PBS item codes, so for clarity a note has also been added to the listings.
Evidence lacking for faster onset of action
There are no clinical efficacy data to show that sumatriptan fast-disintegrating tablets have a more rapid onset of effect in treating migraine than conventional sumatriptan tablets.
In fasted healthy volunteers, the peak plasma concentration of sumatriptan for the 50 mg dose occurred on average 10 minutes earlier with the fast-disintegrating tablet, a difference that is probably not clinically important.1,2 Data from this study were accepted by the Therapeutic Goods Administration (TGA) as demonstrating bioequivalence of Imigran FDT 50 mg with Imigran 50 mg tablets.2
The other PBS-listed brands of sumatriptan 50 mg tablets have been shown to be bioequivalent to Imigran 50 mg tablets, and by indirect comparison, are accepted by the PBAC as being equivalent for the purpose of substitution to Imigran FDT 50 mg.
Substituting brands of sumatriptan
There are now 10 brands of sumatriptan tablets 50 mg on the PBS that pharmacists may substitute for each other (see box below). As for all medicines that are identified in the PBS as being interchangeable, substitute only if the prescriber allows and the patient consents.
PBS-listed brands of sumatriptan tablets 50 mg* that may be substituted
- APO-Sumatriptan
- Chem mart Sumatriptan
- Imigran†
- Imigran FDT
- Pharmacor Sumatriptan 50
- Sumagran 50
- Sumatab
- Sumatriptan-GA
- Sumatriptan Generic Health
- Terry White Chemists Sumatriptan
* Restricted to people with past migraines that have usually failed to respond to analgesics [Authority required (Streamlined)]
† A brand price premium is payable in addition to the standard PBS patient co-payment for concessional and general patients