(Aust Prescr 2004;27:138-41)
Letters, which may not necessarily be published in full, should be restricted to not more than 250 words. When relevant, comment on the letter is sought from the author. Due to production schedules, it is normally not possible to publish letters received in response to material appearing in a particular issue earlier than the second or third subsequent issue.
Quality use of medicines - prescribing for manufacturers or patients?
Editor, - I refer to the editorial 'Quality use of generic medicines' (Aust Prescr 2004;27:80-1).
Confusion resulting from the availability of multi-sourced brands of medications is predictable within our rapidly changing prescribing and dispensing environments.
For decades, prescribing by manufacturers' brand names was manageable when most medications were available as a single brand. It should also be noted that brand names are required for all products as part of Therapeutic Goods Administration (TGA) regulatory requirements.
Australia has a growing generics segment. This is synonymous with growing numbers of brands of the same medications and it is time for current prescribing practices to be reviewed to determine better ways to manage multi-sourced brands.
An Australian Pharmaceutical Advisory Council (APAC) subcommittee has concluded that Australia should move towards increased use of active ingredient names. In the UK, this has served to educate the public and health professionals to identify medications, primarily, by their international (approved) active ingredient names and not by local, brand names.
As per the authors' comments, increased prominence of active ingredient names is being recommended by various health committees to assist patients and professionals.
An APAC subcommittee will shortly deliver a report on the management of these issues. This report will address concerns about confusion related to over-reliance by all stakeholders on brand names. The process has begun to make some simple but essential improvements to the management of all medications by speaking and writing more in the language of medicine and less in the language of marketing.
Mike Hobbs
Director, Sales and Marketing
Hexal Australia
Pyrmont, NSW
Editor, - The article 'Thiazolidinediones - mechanisms of action' (Aust Prescr 2004;27:67-70), states that 'hepatotoxicity does not seem to be associated with the other two compounds (pioglitazone, rosiglitazone)'. Although admittedly this may be referring to the rare but fatal cases of hepatotoxicity associated with troglitazone, it does seem somewhat at odds with the ADRAC Bulletin. This reported on 16 cases of hepatic adverse reactions including elevated liver function tests, jaundice, hepatitis and hepatocellular damage. Although it does add the rider that 'liver enzyme levels may be elevated with diabetes or obesity'.1
Derek Grubb
Pharmacy Department
Bunbury Regional Hospital
Bunbury, WA
References
1. ADRAC. The glitazones – early experience. Aust Adv Drug React Bull 2003;22:6-7.
Dr J.R. Greenfield and Professor D.J. Chisholm, the authors of the article, comment:
In contrast to troglitazone, which was withdrawn because of rare but fatal liver failure, placebo-controlled trials show that the risk of liver function abnormalities (reversible elevations of alanine transferase greater than three times the upper limit of normal) in patients treated with pioglitazone or rosiglitazone is 0.2-0.3% and not different from placebo-treated patients.1 While rare case reports of hepatocellular injury and hepatic failure have been described in patients treated with these newer drugs2, whether liver dysfunction can be definitively attributed to the thiazolidinedione has been challenged.3 As Mr Grubb acknowledges, liver function may be abnormal in patients with diabetes and/or obesity, particularly due to non-alcoholic fatty liver disease. Furthermore, liver function may actually improve following treatment with these drugs, due to a reduction in hepatic lipid content.4 As stated in our article, and the accompanying paper (Aust Prescr 2004;27:70-4), and by the Adverse Drug Reactions Advisory Committee, pharmacovigilance with periodic tests of liver function is recommended, despite the safety of pioglitazone and rosiglitazone.
References
1. Mudaliar S, Henry RR. New oral therapies for type 2 diabetes mellitus:The glitazones or insulin sensitizers. Annu Rev Med 2001;52:239-57.
2. Tolman KG, Chandramouli J. Hepatotoxicity of the thiazolidinediones. Clin Liver Dis 2003;7:369-79.
3. Freid J, Everitt D, Boscia J. Rosiglitazone and hepatic failure. Ann Intern Med 2000;132:164.
4.Festi D, Colecchia A, SaccoT, Bondi M, Roda E, Marchesini G. Hepatic steatosis in obese patients: clinical aspects and prognostic significance. Obes Rev 2004;5:27-42.
Warfarin: balancing the benefits and harms
Editor, - As an eye surgeon I was surprised to read thatwarfarin was contraindicated when eye surgery was contemplated (Aust Prescr 2004;27:88-92). Given that cataract surgery is one of the most common elective surgical procedures performed in this country and most patients are aged over 65, this advice was somewhat at odds with accepted practice. A number of papers have looked at this issue and a study from New Zealand suggested that there was no greater risk of adverse events in patients undergoing surgery being maintained on warfarin, provided their INR was between 2.0 and 2.5.1
T. Hodson
Ophthalmologist
Mount Gambier, SA
References
1. Morris A, Elder MJ. Warfarin therapy and cataract surgery. Clin Experiment Ophthalmol 2000;28:419-22.
Dr M. Borosak, Ms S. Choo and Professor A. Street, the authors of the article, comment:
The contraindications to warfarin indicated in the article were obtained primarily from the product information. The relevant paragraph indicates that any circumstance where the 'hazard of haemorrhage might be greater than the potential clinical benefit of anticoagulation' may constitute a contraindication. It goes on to say that examples of these circumstances may be haemorrhagic tendencies and blood dyscrasias, recent or contemplated surgery of the central nervous system, the eye or traumatic surgery resulting in large open surfaces. The risk:benefit analysis is the key to the decision making related to what is considered a contraindication.
This view is also supported by a study of the management of anticoagulation before and after elective surgery, which presented figures pertaining to such a risk:benefit analysis. The absolute risk of thromboembolism associated with a few days of perioperative subtherapeutic anticoagulation is generally very low while the risk of bleeding if anticoagulated may be relatively high.1
The study quoted by Dr Hodson describes a retrospective review of 28 cataract patients being treated with warfarin (outcomes were available for 23 eyes) who had INRs ranging from 1.0 to 2.4 (median 1.5). There were four haemorrhages, all of which were visually not significant, and there were no thromboembolic phenomena. The conclusion was that with modern techniques cataract extraction can safely and effectively be performed in patients taking warfarin who have an INR of approximately 2.0.
It is our opinion that in all perioperative circumstances the patient's individual risk factors for thrombosis and haemorrhage should be considered before a decision is made to maintain warfarin therapy and the INR level above 2.0.
References
1. Kearon C, Hirsch J. Management of anticoagulation
Editor, - In the article 'Antibiotic prescribing: how can emergence of antibiotic resistance be delayed?' (Aust Prescr 2004;27:39-42) I note the emphasis on using these drugs for the shortest time possible. Is it time to change our advice to patients to 'make sure you complete the course, even if you feel better after a few days'?
The reason for this advice appears to be twofold. Firstly, the infection will recur if incompletely treated. Secondly, the emergence of resistance is facilitated by shorter courses of antibiotics, presumably because relatively resistant strains of the pathogenic bacteria may still be viable at the end of such a course. However, is complete eradication of the pathogen desirable or necessary in the clinical world of bacterial tonsillitis, severe otitis media, bacterial sinusitis, bacterial gastroenteritis, urinary tract infection, impetigo and chest infection? Do we actually have any evidence relating duration of antibiotic courses, emergence of resistant pathogens, and clinical 'cure' in these conditions?
Nancy Sturman
General practitioner
Indooroopilly, Qld
Dr J. Ferguson, the author of the article, comments:
The situation is complex and varies according to the infected site. With infections such as otitis media, when antibiotics are used, the counsel is now to use 'short and sharp' - an adequate dose to eradicate the pneumococcus and short duration to avoid extended selective pressure. Generally, the longer the course, the greater the selective pressure. This is facilitated by the number of bacteria present - an undrained abscess with pseudomonas will see quick emergence of resistance whereas a patient with streptococcal endocarditis will not have resistance emerge despite several weeks of therapy (the bacterial count is much lower and the intrinsic character of the organism less liable to mutational or other resistance acquisition).
Editor, - I would like to draw your attention to the review of insulin glargine (Aust Prescr 2004;27:50-1), particularly the statement that insulin glargine is not suitable for use in patients with type 2 diabetes.
Insulin glargine has an indication for use in type 2 patients in its approved product information. The use of insulin glargine in this patient group continues to be supported by a large body of clinical trial evidence, as well as postmarketing experience in many countries where it has been used in clinical trials or commercially available for almost five years.
The review, which referred to guidelines prepared by the National Institute for Clinical Excellence (NICE) in the UK, has omitted the important qualifying information which NICE made to its general advice on the use of insulin glargine. These guidelines in fact specify quite distinct groups of patients in which insulin glargine should be considered, which taken together account for a significant proportion of all patients with type 2 diabetes.1
In addition, the claim that 'long-term effectiveness of insulin glargine is currently unknown' is, we believe, out of date. There are several published studies involving insulin glargine lasting up to 52 weeks in duration. There is no evidence to date that the effectiveness of insulin glargine diminishes with time.
James Robertson
Senior Medical Advisor
Aventis Pharma
Lane Cove, NSW
References
1. National Institute for Clinical Excellence. Guidance on the use of long-acting insulin analogues for the treatment of diabetes - insulin glargine. London: NICE; 2002. http://www.nice.org.uk/pdf/53_Insulin_analogues_full_guidance.pdf [cited 2004 Nov 8]
Editorial comment:
The Australian Prescriber comment accurately reflected the conclusion of the National Institute for Clinical Excellence (NICE) that insulin glargine 'is not recommended for routine use for people with type 2 diabetes who require insulin therapy'. The NICE recommended that insulin glargine should only be considered, in type 2 diabetes, for patients:
- who require assistance from a carer or healthcare professional to administer their insulin injections
- whose lifestyle is significantly restricted by recurrent symptomatic hypoglycaemic episodes
- who would otherwise need twice-daily basal insulin injections in combination with oral antidiabetic drugs.
