PRESCRIBING SUPPORT TEAM AUDIT: CARDURA XL (Updated Sept 09) DATE OF AUTHORISATION: AUTHORISING GP: PRESCRIBING SUPPORT TECHNICIAN: SUMMARY Cardura XL is a once daily, extended release preparation of doxazosin designed to reduce the incidence of side-effects associated with the initiation of the drug. It does not however, confer any advantage over standard release doxazosin in the long-term and is considerably more expensive. Standard release doxazosin may also be given in a once daily regimen 1. OBJECTIVE To change suitable patients from Cardura XL to standard release generic doxazosin. RATIONALE Cardura XL is associated with lower peak plasma levels than standard release doxazosin 2 and is therefore claimed to eliminate the need for dose titration on initiation of the drug. Overall however, adverse events associated with both preparations are similar 2. This suggests Cardura XL is no more tolerable following initiation of the drug than standard release doxazosin.
Trough levels at 24 hours of both preparations are similar 2, therefore patients being transferred from Cardura XL to standard release doxazosin should be able to carry on taking the drug in a once daily regimen. This would appear to be supported by Pfizer s Summary of Product Characteristics (SPC) for Cardura 1 as it states that it is used in a once daily regimen. There is no mention of having to split the daily dose even at the maximum licensed dose of 16mg. Pfizer s SPC for Cardura XL 2 does not give any advice on transferring patients from the extended release preparation to the standard release version. The current cost of generic standard release doxazosin is as follows:- 28 x 1mg tablets = 0.93 3 28 x 2mg tablets = 1.00 3 28 x 4mg tablets = 1.49 3 In comparison, the current cost of Cardura XL is :- 28 x 4mg tablets = 5.70 4 28 x 8mg tablets = 9.98 4 At these prices, transferring one patient from 8mg of Cardura XL once daily (the maximum licensed dose 2 ) to 8mg of standard release doxazosin once daily, would save NHS Dumfries and Galloway 91 each year. Therefore, given that Cardura XL does not appear to offer improved tolerability over standard release doxazosin following initiation of the drug and that it costs over 100 per patient per year more, it is proposed that all patients currently receiving a repeat prescription for Cardura XL be transferred to the same dose and frequency of the standard release preparation. METHOD A computer search for patients receiving repeat prescriptions for Cardura XL. Once these patients are identified, Cardura XL will be deleted from their repeat prescription list and standard release generic doxazosin added. The same dose and directions will be used for the new doxazosin prescription as had been on the Cardura XL prescription. A letter will be sent to each patient affected by the switch.
The practice will scan the letter into each patient s file or, alternatively, place the letter in the patient s notes. A note will be recorded in the patient s computer record detailing the action taken. The local community pharmacy/pharmacies will be informed about the switch in advance of it taking place. EXCLUSION CRITERIA Patients who have previously been switched to Cardura XL because they have experienced side-effects on standard release generic doxazosin. Any criteria for exclusion as specified by the authorising GP. SUGGESTED CRITERIA FOR REFERRAL TO PRACTICE Any criteria specified by the practice. CHANGES TO REPEAT PRESCRIBING 1. The audit must be checked and agreed with a GP in the practice prior to work being undertaken by the Prescribing Support Technician 2. Agreement is made between the Practice and the Prescribing Support Technician on a suitable date for implementation. 3. It is recommended that the practice/lhp Pharmacist notify local community pharmacies of the impending change in prescribing. 4. The Prescribing Support Technician conducts a search of the Practice Clinical System to identify patients currently prescribed the preparations as authorised on the Prescribing Review form. 5. Patients are assessed, with respect to suitability for transfer to the preferred product, on an individual basis by the Precribing Support Technician. 6. Patients who, in the professional judgement of the Prescribing Support Technician, are considered unsuitable for transfer will be identified and referred back to the practice. 7. No patient may be changed beyond the scope of the SPC unless authorised by the prescriber.
8. All changes to prescribing must be recorded within the presribing field and, wherever possible, an indication recorded for the medication that is added. 9. Dose and rates of usage should remain the the same or equivalent to theoriginal prescription wherever possible. 10. Each patient should be informed of any changes made in accordance with the Practice s preferred mode of communication. The Prescribing Support Team recommends personalised written communication sent from the Practice. Additional information e.g. patient leaflets may be included wherever possible. 11. If the patient is under the age of 16 then any information should be addressed to the patient s parent or guardian. 12. If the patient is in residential care or has their medication otherwise supervised, e.g. Dosette dispensing, information regarding any changes should also be communicated to the relevant service providers. 13. The Prescribing Support technician will communicate information about the review to relevant personnel within the practice e.g. receptionists, nurses and will, if appropriate, create on-screen reminders on the Clinical System. 14. A project file is retained by the Practice containing a list of patients involved, patient letter templates and any individual information sent, a copy of the protocol and prescribing review form and contact details for the Prescribing Support Team. 15. The Prescribing Support Technician may record statistics of the review for report purposes and analysis of the review. No information regarding individual patients leaves the practice. 16. A follow-up audit will take place within 6 months.
REFERENCES 1. Cardura - Summary of Product Characteristics. Pfizer Limited. Last reviewed on 19/11/2003. http://emc.medicines.org.uk/emc/industry/default.asp?page=displaydo c.asp&documentid=1456 2. Cardura XL Summary of Product Characteristics. Pfizer Limited. Last reviewed on 16/06/2004. http://emc.medicines.org.uk/emc/industry/default.asp?page=displaydo c.asp&documentid=4484 3. Scottish Drug Tariff Part 7 Drugs and Preparations with Tariff price: July 2009 http://www.isdscotland.org/isd/files/tar_jul_09.xls 4. British Medical Association and Royal Pharmaceutical Society of Great Britain. British National Formulary. London: BMA, RPS, 2009: p98 (No 57).
Patient name names Address 1 Address Address 2 Address 3 Address 4 Address 5 Postcode Partners Practice Practice Tel No. Practice Fax No. Date Dear Mr/Mrs As part of a review of prescribing, NHS Dumfries and Galloway are considering some changes to the drugs prescribed regularly for high blood pressure. The next time you request Doxazosin MR tablets (Cardura XL) you will notice we have changed your prescription to Doxazosin tablets. This means that you will still be getting the same drug at the same strength but from a preparation that releases into your body quicker. Current evidence demonstrates that both preparations are effective at lowering blood pressure and that they have the same side-effects. This change has been made to help doctors to continue to use high quality treatments while making the most effective use of available resources. We propose to introduce the change with your next prescription. Please finish your tablets as normal and then start the new tablets as directed. Should have any queries, please contact the Surgery on the number above or, alternatively, you can contact a member of the Prescribing Support Team on 01387 244517. Yours sincerely Partner s names Prescribing Support Team Please try to remember to order your medication using the new name next time. Please finish your existing supply of medicine before starting on the new drug or dosage unless otherwise instructed by your GP.