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Letters to the Editor
(Aust Prescr 1999;22:28-31)
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.
Editor, - In his editorial `Quality use of medicines - where to next' (Aust Prescr 1998;21:58-9), Professor R. Moulds described his vision of electronic prescribing with the 3 main independent Australian sources of therapeutic and drug information coming together in an electronic version linked to prescribing packages. This is a laudable objective; however, the obstacles to this therapeutic Utopia are more than just technical as has been underlined by Dr J. Dowden in his editorial `www.australianprescriber.com' (Aust Prescr 1998;21:59).
There are already on the market several software packages for managing patient files, several drug databases and several electronic prescribing packages. To choose between them, practitioners will have to ask the same questions as when choosing between other traditional sources of information e.g. medical journals. How has the electronic prescribing package been developed? Does it provide reliable, up-to-date, objective information about drugs? Is the information independently derived? Is it sponsored by a drug company? All these questions are important because, if an electronic prescribing package is biased (voluntarily or not), it may adversely influence prescribing practices.
If we really want electronic prescribing to improve therapeutic practices and patient outcomes, it is essential that it be underpinned by high quality independent comparative drug information. This will require the long-term and strong commitment of the government and/or professional organisations. Otherwise, competition from cheaper, but potentially biased, industry-subsidised electronic packages may change the dream of a therapeutic Utopia into a nightmare.
G. Gabb and A. Vitry
Australian Medicines Handbook
Adelaide, S.A.
Editor, - I read with interest Drs Tay and McGrath's article `Diagnosis of deep vein thrombosis' (Aust Prescr 1998;21:76-9) and the challenge it frequently presents. I note that, in the management of isolated calf vein thrombosis without ongoing risk factors, they advocate withholding anticoagulation and repeat the scan in 5-7 days.
An increasing body of literature is finding that non-propagating isolated calf vein thrombosis is indeed embolising to produce both `serious' symptomatic pulmonary emboli and `asymptomatic' pulmonary emboli that later result in pulmonary hypertension.
I refer particularly to a Scandinavian study (specifically designed to asses the source of emboli) which showed >35% of patients had an isolated calf deep vein thrombosis.1
Other studies found that 40%2 to 46%3 of emboli originated in the calf. A 1993 study4 assessed patients with paradoxical emboli via patent foramen ovale; the source was isolated to calf veins in 15 of 24 patients.
While it may be contentious as to the true incidence of isolated versus propagated calf deep vein thromboses embolising, I think it is being increasingly recognised that isolated calf deep vein thromboses are not as `benign' as was once thought. If this is true, given the potential for both symptomatic and `asymptomatic' pulmonary emboli to have a high morbidity, should we be anticoagulating these patients rather than repeating their scan subsequently? I would be interested to hear the authors' opinion on this issue.
Rob Ojala
Emergency Department Registrar
Melbourne, Vic.
R E F E R E N C E S
1. Havig O. Deep vein thrombosis and pulmonary embolism. An autopsy study with multiple regression analysis of possible risk factors. Acta Chir Scand Suppl 1977;478:1-120.
2. Moreno-Cabral R, Kistner RL, Nordyke RA. Importance of calf vein thrombophlebitis. Surgery 1976;80:735-42.
3. Kohn H, Konig B, Mostbeck A. Incidence and clinical feature of pulmonary embolism in patients with deep vein thrombosis: a prospective study. Eur J Nucl Med 1987;13 (Suppl):11S-15S.
4. Stollberger C, Slany J, Schuster I, Leitner H, Winkler WB, Karnik R. The prevalence of deep venous thrombosis in patients with suspected paradoxical embolism [published erratum appears in Ann Intern Med 1994;120:347]. Ann Intern Med 1993;119:461-5.
Dr J.C. Tay and Dr M. McGrath, authors of the article,
comment:
Dr Rob Ojala's correspondence highlights one of the current controversies
in the management of deep vein thrombosis. As yet, there is insufficient evidence
to be dogmatic about management of the isolated calf vein thrombosis, although
we would support Dr A.S. Gallus' recommendation about the treatment of symptomatic calf
vein thrombosis (Aust
Prescr 1998;21:64-6). The emphasis of our review was to describe the diagnostic
test options. The value of colour duplex ultrasonography is to provide a means
of ongoing non-invasive surveillance of the deep vein thrombosis. This is of
particular relevance if a decision is made not to include anticoagulation in
managing an asymptomatic isolated calf vein thrombosis.
Editor, - Apropos the article `When to use a new drug' (Aust Prescr 1998;21:67-9), I am reminded of the advice given to me by the late, beloved Sir Kenneth Noad, when I was a houseman, years ago, at Sydney Hospital. `John, dear boy, always use a new drug when it is very new because that's when it is said to be most efficacious.'
John Watson
General Practitioner
Vaucluse, N.S.W.
Editor, - I refer to the letter from Dr Justin Coleman and to Dr Paul Nisselle's comment (`Use of two needles' Aust Prescr 1998;21:60-1). There is one type of injection where it is important to use two needles and that is when giving certain vaccines. The outside of the needle may be contaminated by the toxoids and there is an increased risk of local reactions in the superficial tissues and along the track of the needle.
W.A.C. Young
General Practitioner
Mornington, Vic.
Dr Margaret Curran, Associate Medical Director, CSL Pharmaceuticals,
comments:
Thank you for the opportunity to comment on Dr Young's letter about using
two needles for injections.
The Australian Immunisation Handbook1 recommends that, `for vaccines which are drawn up through a rubber bung, or are reconstituted, a new needle should be used for administration. If the vaccine has been drawn up from an open vial, the same needle may be used'.
For aluminium adsorbed vaccines, there is some suggestion in the literature2,3,4,5 that injection technique may contribute to the severity of local reactions, including abscess formation at the injection site, as a result of the antigen seeding the needle track.
The approved prescribing information for adult tetanus toxoid with diphtheria toxoid (ADT) and tetanus toxoid (Tet-Tox) states that local reactions can be minimised if care is taken to ensure that the intramuscular injection is given deeply and that none of the material (toxoid) is deposited superficially or along the track of the needle.
The approved prescribing information for both children's diphtheria toxoid with tetanus toxoid (CDT) and diphtheria, tetanus, pertussis vaccine (Triple Antigen) suggests the following precautions:
• When withdrawing the antigen into the syringe, avoid any residue on the outer surface of the needle.
• Administer by deep intramuscular injection.
• Inject slowly so as to allow the injected material to disperse instead of coming up the needle track.
R E F E R E N C E S
1. National Health and Medical Research Council. The Australian immunisation handbook. 6th ed. Canberra: Australian Government Publishing Service, 1997:16.
2. Sako W, Treuting WL, Witt DB, Nichamin SJ. Early immunization against pertussis with alum precipitated vaccine. JAMA 1945;127: 379-84.
3. Bernier RH, Frank JA, Nolan TF. Abscesses complicating DTP vaccination. Am J Dis Child 1981;135:826-8.
4. Fawcett HA, Smith NP. Injection-site granuloma due to aluminium. Arch Dermatol 1984;120:1318-22.
5. Wiesenthal AM, Lauer BA. Syringe preparation technique and minor adverse reactions to diphtheria-tetanus-pertussis immunization. Pediatr Infect Dis J 1987;6:1048-50.
Editor, - I refer to the comment on tacrolimus published recently in your `New drugs' section (Aust Prescr 1998;21:81-2).
The study referred to was published in 1994 as the preliminary experience of 8 respected European centres.
Follow-up data from the same trial has been subsequently published.1 This latter report describes a similar safety profile of tacrolimus compared with cyclosporin, but with a less problematic convalescence. It is stressed that careful attention to dosing and blood level assessment is necessary. Concentrations of both tacrolimus and cyclosporin require routine post-transplant monitoring, both are metabolised by cytochrome P450 and both have similar drug interactions. Toxicity of both agents is largely dose related. In the earlier study, blood levels of tacrolimus were not available at the time of dose adjustments and the doses initially recommended were inappropriately high. Continuous infusion of tacrolimus was used initially and this practice has now been abandoned by most programs because of the recognised greater toxicity of the parenterally administered drug.
The comparison between cyclosporin and tacrolimus has less relevance in 1998 as the former has been largely replaced with the microemulsified version of cyclosporin. This new formulation and tacrolimus are both well absorbed from the gut immediately after transplantation.
Stephen V. Lynch
Associate Professor of Surgery
Deputy Director
Queensland Liver Transplant Service
Royal Children's Hospital
Herston, Qld
R E F E R E N C E
1. Williams R, Neuhaus P, Bismuth H, McMaster P, Pichlmayr R, Caine R, et al. Two-year data from the European multicentre tacrolimus (FK506) liver study. Transpl Int 1996;9(1 Suppl):144S-150S.
Editor's note:
The Pharmaceutical Benefits Pricing Authority's Therapeutic Relativity
Sheets (August 1998) state `Tacrolimus was accepted as being more effective
than cyclosporin and less costly'.
Strategies to assist patient compliance with lifestyle changes
Editor, - The excellent article by Dr Glyn Brokensha, `Strategies to assist patient compliance with lifestyle changes' (Aust Prescr 1998;21:92-4), reflected many of the practices and problems of pharmacists as well as doctors. At the University of Sydney, we teach communication courses to pharmacy students, and many of us carry this over into our continuing education teaching, all with the aim of optimising patient care. One of the things we do is teach the practice of asking open-ended questions of the patient with the aim of filling in information gaps. The answer to a favourite question in my practice, namely, `What else did the doctor tell you to do besides take this medication?', is usually very little if anything. This might be because the patient has forgotten. It is certainly very rare to see any kind of written treatment or lifestyle plan. Pharmacists also experience big problems when we uncover doubts about the doctor's `clear and specific intention' via the prescription, based on our information gathering and the counselling advice we give to the patient. Often these doubts are based on information about the patient's treatment that may have been overlooked by the doctor and not asked by the patient.
It seems to me that society and/or the academic medical community expect superhuman feats of patient care from general practitioners, all to be accomplished in a limited time and also involving (essential) detailed and specific lifestyle prescription plans. However, there are many pharmacists who would like to help. Many pharmacists have installed computer databases in their pharmacies that are capable of providing lifestyle advice in addition to detailed drug information. The lifestyle advice and fact cards on a huge variety of different disease states are often supplied at no cost to the patient. Many of us are out here contributing to patient care and also eager to assist doctors who search us out to help their patients.
Ben Basger
Practitioner/Teacher in Pharmacy Practice
University of Sydney
Sydney, N.S.W.
Editor, - One of our patients who was receiving disodium pamidronate 90 mg (Aredia) has developed gynaecomastia. We then conducted a survey within our clinic to determine if there were other patients showing similar or related adverse effects during treatment with pamidronate.
The results showed that, of the 13 patients surveyed, two males were experiencing gynaecomastia; one female, tender and swollen breasts; and another patient had developed a cyst below the nipple.
No other drugs were indicated or suspected as being the cause. Whilst these adverse effects have not resulted in the need to cease treatment in any of these patients, it is worthwhile to note that these adverse effects may occur with the use of disodium pamidronate.
Lee Russell
Oncology Pharmacist
Sydney Haematology and Oncology Clinics
Hornsby, N.S.W.
Cefaclor and serum sickness-like reactions
Editor, - The association between serum sickness or serum sickness-like reactions and cefaclor has been well documented.1-9 The Pharmaceutical Benefits Advisory Committee has recently amended the listing for cefaclor in the Schedule of Pharmaceutical Benefits. The listing now includes the caution that `serum sickness-like reactions have been reported with this drug, especially in children'. In response, the Medical Director of Eli Lilly, the manufacturer of Ceclor, has circulated a letter to all doctors (22 October 1998). This letter misconstrues the facts and is misleading.
The letter states that the amendment regarding serum sickness-like reactions is unnecessary as `the incidence has remained rare (0.024%) and unchanged since launch'. In fact, published studies have estimated a rate 20 times or more higher than that quoted in the drug's product information.1,2 Indeed, in the article from the Lilly Research Laboratories that quotes the 0.024% figure, the author himself states: `This incidence differs from findings reported in the literature'!8 Most of the subjects in that study were adults and the rate was higher in children.8
The letter makes the disingenuous statement that serum sickness has been associated with many antibiotics. Several studies have found that the rate is higher for cefaclor than other antibiotics.1-5 During 4 years of retrospective and prospective monitoring of serum sickness at this hospital, 48 children have been identified with antibiotic-associated serum sickness.1,7 Of these, 42 (88%) were related to cefaclor. In the prospective study, cefaclor was responsible for 95% of serum sickness linked to antibiotics.7 In another study of 3487 children who had been prescribed amoxycillin, cefaclor, or both, the relative risk of serum sickness after cefaclor was 19 times that of amoxycillin.2
The letter suggests that serum sickness-like reactions differ from classic serum sickness. This distinction is not clinically relevant. The clinical features are not trivial; allergic skin disease, arthritis and fever may be present in both. Furthermore, 25% or more result in presentation to an emergency department or admission.9 The letter also states that `no such caution has been added anywhere (else in the world)'. However, the Canadian Adverse Drug Reaction Monitoring Program issued a similar caution in 1996.9
I concur with the letter's advice that the choice of antimicrobial therapy should be based on the likely pathogens and the spectrum of activity of the antibiotic. For these reasons, many conditions for which cefaclor is currently prescribed (otitis media and tonsillitis) would be better managed with either no antibiotic or a narrow-spectrum penicillin (phenoxymethylpenicillin or amoxycillin).
Finally, the letter recommends to doctors that they be wary of those who `may try to misrepresent or exaggerate the facts'. It would behove Eli Lilly to heed its own advice.
Michael Starr
Consultant Paediatrician and Infectious Diseases Fellow
Department of Microbiology and Infectious Diseases
Royal Children's Hospital
Melbourne, Vic.
R E F E R E N C E S
1. Parshuram CS, Phillips RJ. Retrospective review of antibiotic-associated serum sickness in children presenting to a paediatric emergency department [letter]. Med J Aust 1998;169:116.
2. Martin J, Abbott G. Serum sickness like illness and antimicrobials in children. N Z Med J 1995;108:123-4.
3. Stricker BH, Tijssen JG. Serum sickness-like reactions to cefaclor. J Clin Epidemiol 1992;45:1177-84.
4. Hebert AA, Sigman ES, Levy ML. Serum sickness-like reactions from cefaclor in children. J Am Acad Dermatol 1991;25:805-8.
5. Heckbert SR, Stryker WS, Coltin KL, Manson JE, Platt R. Serum sickness in children after antibiotic exposure: estimates of occurrence and morbidity in a health maintenance organization population. Am J Epidemiol 1990;132:336-42.
6. Levine LR. Quantitative comparison of adverse reactions to cefaclor vs. amoxycillin in a surveillance study. Pediatr Infect Dis 1985;4:358-61.
7. Parshuram CS, Nash M, Phillips RJ. Serum sickness in a paediatric emergency department: the role of cefaclor. J Paed Child Health. In press.
8. Hyslop DL. Cefaclor safety profile: a ten-year review. Clin Ther 1988;11(A Suppl):83S-94S.
9. Cefaclor-associated serum sickness-like reaction. Can Med Assoc J 1996;155:913-4, 917-8.
