Trandolapril with verapamil sustained release (SR) in a fixed-dose combination tablet (Tarka) will be listed on the PBS on 1 May 2007. This listing is restricted to people already stabilised on antihypertensive treatment with trandolapril 4 mg and verapamil SR 240 mg1 who wish to reduce the number of tablets they take each day. Using the combination tablet will save one co-payment per month.
Combination tablet doses have limited dosing flexibility
While the maximum recommended daily dose for trandolapril (4 mg) for hypertension is contained in the fixed-dose combination, verapamil SR tablets may be titrated up to a maximum dose of 240 mg twice a day for hypertension.2 Hypertension is a condition that changes over time, so dose adjustments may be required but are not possible with this preparation.
Combination therapy for hypertension usually contains a diuretic2, so relatively few patients would be stabilised on trandolapril and verapamil for hypertension. Trandolapril 4 mg with verapamil SR 240 mg as a fixed dose combination is more effective than either drug dose given as monotherapy.3
Starting the combination tablet
Weigh the potential convenience of a switch against the risk of confusion and medication errors. Advise people switching to the combination tablets to stop taking their separate trandolapril and verapamil SR tablets. Advise patients that adverse effects appear to be similar to those of the individual components.4
- Pharmaceutical Benefits Advisory Committee. November 2006 positive recommendations. Canberra: Australian Government Department of Health and Ageing, 2006. http://www.health.gov.au/internet/wcms/publishing.nsf/Content/pbacrec-nov06-positive (accessed 23 January 2007).
- Rossi S, ed. Australian Medicines Handbook. Adelaide, Australian Medicines Handbook Pty Ltd, 2007.
- Pharmaceutical Benefits Advisory Committee. Public summary document: Trandolapril with verapamil 4 mg-240 mg. Canberra: Australian Government Department of Health and Ageing, 2006. http://www.health.gov.au/internet/wcms/publishing.nsf/Content/pbac-psd-trandolapril-nov06 (accessed 23 January 2007).
- Abbott Australasia. Tarka product information. 8 December 2006.