PJ Online | MM: Putting some sense into brand-switching of diltiazem

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Medicines Management
Issue no 6, pp13-14
November/December 2002

Features

Putting some sense into brand-switching of diltiazem

In many cases, different generics have the same clinical effects as each other — but not in the case of diltiazem. Monica Sharma Kapoor (Prescribing Support Pharmacist, Doncaster West Primary Care Trust) describes how she tried to simplify matters for patients in Doncaster

Although, in many instances, prescribing generically is welcomed, the BNF recommends that modified-release longer-acting formulations of diltiazem be prescribed by brand because different preparations may not have the same clinical effect. In the "generic-craze" drugs such as diltiazem have inadvertently been switched from brand to generic.

There are several different brands of diltiazem on the market — 13 at the last count. Different pharmacies stock various brands of diltiazem and patients who "pharmacy-hop" may find that they receive a different brand of diltiazem each time they have their prescription dispensed.

This prompted me to look into whether or not it was possible to assign a brand to diltiazem modified-release preparations when they were prescribed generically so that patients would continue to receive the same product — wherever they took their prescription.

Choosing the brand

Before beginning this exercise I needed to choose a brand of diltiazem to switch patients to. I opted for Zemtard XLŽ as the brand of choice; it is a convenient once-daily formulation, and considerably cheaper than other alternatives.

It is also one of the once-daily formulations recommended by Doncaster West Primary Care Trust in its "Drug Rationale and Evidence-Based Formulary".

Searches on EMIS PCS/MicroDoc revealed that although some patients were on unbranded once-daily preparations, the most common prescriptions seen were for diltiazem m/r 60mg tablets, one three times daily and diltiazem m/r 90mg tablets, one twice daily. For patients on unbranded once-daily preparations, I was faced with the dilemma of either changing all prescriptions to Zemtard XLŽ or changing prescriptions to the brand patients were stabilised on.

I decided to stick to the brand the patient was stabilised on in one practice (ascertained by liaising with local community pharmacists or contacting the patient) and change to Zemtard (XLŽ) for patients in another practice.

For those patients on multiple doses of diltiazem, as well as complying with the clinical recommendation of prescribing by brand, I was able to apply strength alignment hence reducing the number of tablets/capsules the patient needed to take.

Changes in letters

Patients were informed of any changes to their regimen by letter — and the three I used are reproduced here.

As I expected, there were no concerns raised from patients whose prescription was amended to state the brand of diltiazem they were already receiving. To date, I have not had any queries from patients who have been changed from their once-daily formulation of diltiazem to Zemtard XLŽ. This is reassuring, and I am now switching all once-daily formulations to Zemtard XLŽ for patients in other practices.

Letter specifying a brand of diltiazem m/r

Practice details

Date

Dear __________________________ ,

Re: Diltiazem modified-release capsules

As a Practice, we are constantly reviewing our repeat prescriptions to ensure that our patients get the best, most cost-effective treatment available. We are currently focusing on the use of diltiazem modified-release capsules.

Although most medicines should be prescribed using their real or generic name, diltiazem is one of the few medicines in which a specific brand should be prescribed. The reason for this is that different brands of diltiazem may differ slightly, and it is better to stick to one particular brand.

I understand from your community pharmacist that the brand of diltiazem you take is ______________ . I have therefore amended your repeat prescription to print this brand name on future prescriptions.

I hope you will find this satisfactory; should you have any queries regarding this change, please contact me on the above number on _____________, between ____ and ____.

Yours sincerely,

Pharmacist

On behalf of (GPs).

Letter explaining change of brand

Practice details

Date

Dear __________________________ ,

Re: Diltiazem modified-release capsules

As a Practice, we are constantly reviewing our repeat prescriptions to ensure that our patients get the best, most cost-effective treatment available. We are currently focusing on the use of diltiazem modified-release capsules.

Although most medicines should be prescribed using their real or generic name, diltiazem is one of the few medicines in which a specific brand should be prescribed. The reason for this is that different brands of diltiazem may differ slightly, and it is better to stick to one particular brand.

Doncaster West Primary Care Trust produces a list of carefully chosen medicines that they recommend for prescribing; for diltiazem one of the brands they recommend is Zemtard XLŽ.

We would therefore like to alter your repeat prescription from diltiazem modified release capsules ____mg, one daily to Zemtard ____XLŽ, one capsule every morning.

You do not need to do anything; your repeat prescription will be changed automatically.

Should you have any queries regarding this change, or if you feel the new medication is not suiting you, please contact me on the above number on ____________, between ____ and ____.

Thank you for your continued support.

Yours sincerely,

Pharmacist

On behalf of (GPs)

Letter explaining change of brand/dosing

Practice details

Date

Dear __________________________ ,

Re: Diltiazem modified-release tablets

As a Practice, we are constantly reviewing our repeat prescriptions to ensure that our patients get the best, most cost-effective treatment available. We are currently focusing on the use of diltiazem modified-release tablets.

I note that you currently take diltiazem modified-release ____mg tablets at a dose of ____ tablet ____ daily. This is a total daily dose of ____mg diltiazem.

A diltiazem modified-release ____mg capsule is available, called Zemtard ____XL. This only needs to be taken once daily.

I would like to alter your current prescription for diltiazem modified-release ____mg tablets to Zemtard ____XL (diltiazem modified-release ____mg capsules). Take one every morning.

Please note that the actual daily dose of diltiazem has not changed, you just need to take one capsule daily now.

You do not need to do anything, as your repeat prescription will be changed automatically.

I hope you find this change satisfactory; should you have any queries, or if you feel the new medication is not suiting you, please contact me on the above number on _______________, between ____ and ____.

Thank you for your continued support.

Yours sincerely,

Pharmacist

On behalf of (GPs)

Concerns about single doses

I have had concerns raised from patients previously on multiple doses of diltiazem who have been changed to Zemtard XLŽ. Patients are concerned that taking, for example, 180mg of diltiazem as a single daily dose rather than 60mg three times daily will be "too much" for them. This came as a surprise to me as this has not been an issue when I have conducted strength alignment exercises in the past. However, with reassurance, and the option to revert back to the former dosing, most patients are willing to give Zemtard XLŽ a go.

Having branded diltiazem products in most of the practices I work in, I am now awaiting PACT data for the relevant time period to see how successful this switch has been, and I will report on this for Medicines Management at a later date.

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