Letters to the Editor
(Aust Prescr 1995;18:4-7)
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.
Recommendations for pneumococcal vaccination
Editor, With respect, the article 'Recommendations for pneumococcal vaccination', a policy developed by the Thoracic Society of Australia and New Zealand (Aust Prescr 1994;17:41) is not a recommendation, it is a 'negative recommendation'.What is the prescribing doctor to make of it? It starts with 'Analysis of the data available does not support a public health strategy to vaccinate all individuals in a particular atrisk group.' The article therefore advises not to immunise if a patient does not fall into an atrisk group, but does not advise us to whom within the atrisk groups we should offer the vaccine. That is the question that the policy should address.
C.A.W. Collin
General Practitioner
Naracoorte, S.A.
Professor J.P. Seale, the President of the Thoracic Society of Australia and New Zealand, comments:
There are many situations in clinical medicine where the evidence to support one or other approach is incomplete and the efficacy of pneumococcal vaccinations is one such example. This contrasts with the published evidence for other vaccines (e.g. for polio) where the efficacy is such that a firm recommendation for universal immunisation constitutes sound public health policy.
The Thoracic Society of Australia and New Zealand invited one of its members, Dr Paul Torzillo, to review the published literature on pneumococcal vaccine.1 The review found that the efficacy of pneumococcal vaccine was insufficient to justify comprehensive vaccination of all individuals in all the atrisk groups, but the published reports implied that patients with severe disease in the designated categories would probably gain some protection.
Against this background of incomplete published data, recommendations for vaccination cannot be absolute. It is an inevitable consequence of producing summary recommendations which have been derived from a careful analysis of the literature (without publishing the review article itself) that some of the nuances will be lost. I would commend Dr Torzillo's article to those readers who wish to obtain a more detailed appreciation of the background to these recommendations.
In our constant quest for evidencebased clinical practice, we must be careful not to overinterpret the findings of published papers in the interests of simplicity. To do so would be to move down the road towards 'cook book' medicine.
Reference
1. Torzillo P. Pneumococcal vaccine: current status. Aust NZ J Med 1993;23:285-90. Editor, I refer to Professor Reynolds' excellent review of the safety implications of toothpaste ingredients (Aust Prescr 1994;17:49-51).
Probably the agents most likely to cause an allergic reaction are methyl and propyl parahydroxybenzoates, which seem to be the most commonly used preservatives in toothpastes available in Australia. As far as I am aware, SensodyneF (regular and gel) and the entire Aim and Colgate ranges are free of any preservative.
Professor Reynolds' discussion of the potential hazards of ingestion of silica reminds me that, not only are siliceous earths used as abrasives, but also that hydrated silica (silica gel), colloidal anhydrous silica and aluminium magnesium silicate are often used as thickening/binding agents. A few toothpastes are silicafree, including Macleans Regular Mint, OralB Dental Paste, Colgate Fluoriguard (regular and cool mint only), Ultrabrite and Dentagard.
The use of gum arabic (gum acacia), gum tragacanth and Indian tragacanth (karaya) as binders/thickeners is less common nowadays due to a possibility of sensitisation reactions. Carrageenan gum (which incidentally is identical to Irish Moss extract), guar gum, xanthan gum, silica compounds and cellulose derivatives seem to be the most commonly used.
The only sorbitolfree toothpaste that I can trace is Macleans Smokers Toothpaste! Of course, sorbitol is not the only potential laxative in toothpastes since several of the thickening/binding agents may exert this effect if swallowed in sufficient quantity.
Toothpastes containing 0.3% triclosan, as a plaqueinhibiting antibacterial, are currently readily available (e.g. Colgate Total and the Aim range).
T.E. Bridges
Senior Lecturer in Pharmacology
Department of Dentistry
University of Adelaide
Adelaide, S.A.
Professor E.C. Reynolds, the author of the article, comments:
In my article I stated that occasionally the flavours, colourings or preservatives of toothpastes can cause allergic reactions. My reference1, and also another2, state that the flavourings are the most common allergens. In one case where the preservatives as well as the flavourings were involved, only the preservative chloroacetamide was an allergen, even though the preservatives also included benzoates.
After consideration of a large number of studies, it was concluded in the review that silicacontaining toothpastes are safe and effective.
The FAO/WHO has recommended sorbitol intake to be less than 150mg/kg/day. For a 10 kg child, this is equivalent to 1.5 g of sorbitol per day, and for a 70% sorbitolcontaining children's toothpaste, this would be equivalent to 2.1 g of toothpaste ingested per day, a quantity that could easily be achieved by unsupervised brushing. Binders are 1-2% of the toothpaste. Therefore, to ingest the same quantity of binder, the child would have to ingest 100-200g (1-2 tubes) of toothpaste.
The reason why triclosan was included as an antimicrobial toothpaste ingredient in my review was because it is an active ingredient in Colgate's Total which is available in Australia. Triclosan is only an ingredient in the Aim Gum Health variant which does not have wide distribution in Australia relative to the standard Aim. The point I was making in my review was that triclosancontaining pastes are not available in the U.S.A. The Food and Drug Administration would not allow triclosan to be marketed as an antimicrobial toothpaste additive until its efficacy and safety had been established.
References
1. Machackova J, Smid P. Allergic contact cheilitis from toothpastes. Contact Dermatitis 1991;24:311-2.
2. Andersen KE. Contact allergy to toothpaste flavours. Contact Dermatitis 1978;4:195-8.
Nonpharmacological treatment of back pain
Editor, I refer to Professor Murtagh's article on the nonpharmacological treatment of back pain (Aust Prescr 1994;17:33-6).In the relief of pain, including back pain, transcutaneous electrical nerve stimulation (TENS) has a place, provided certain criteria are met. If correctly applied, a central effect does occur (with elevation of the pain threshold), thereby reducing pain and agitation, and minimising any associated narcotic withdrawal effects. The works of Professor J.S. Han have proven that TENS, if applied to certain specific points, e.g. the first interosseus motor point of the thumb, produces a rise in endorphins in both the spinal cord and brain with an elevation of cortisone levels in the blood stream.1 The work of Professor G. Ulett has proven that the effect is not caused by suggestion alone.2
This response is determined not only by the correct placement of the conducting pads, but also by the frequency of the stimulation. Stimulation at two cycles per second (2 Hertz) releases the beta endorphins, 15 Hertz releases the metenkephalins and 100 Hertz releases the dynorphins.
The use of these devices also has the advantage of economy and ease of use, even to the point of supervised selfuse.
James J. Nichols
Psychiatrist
Belmont, N.S.W.
References
1. Han JS, Sun LS. Differential release of enkephalin and dynorphin by low and high frequency acupuncture in the central nervous system. Acupuncture the Scientific International Journal 1990;1:19-27.
2. Ulett GA. Beyond yin and yang; how acupuncture really works. St Louis, Missouri: Warren H. Green, 1992.
Professor J.E. Murtagh, the author of the article, comments:
TENS does have a place in the management of back pain. In 1975, a survey of major pain centres in the U.S.A. showed around 2000 patients with chronic pain of various aetiologies were being treated with TENS. Treating practitioners estimated about one third of these were achieving satisfactory pain control with TENS alone.1
There have been many uncontrolled studies which show in a general way very good to excellent response rates to TENS in low back pain.2
Where intense high frequency TENS has been compared with placebo in doubleblind crossover studies, TENS has been shown to be more effective in relieving chronic pain.3 Other studies have indicated that intense TENS is no better than placebo applied with strong suggestion, in treating pain.4 This of course does not preclude the use of TENS as a therapeutic modality, especially as it is largely well tolerated and free of adverse effects. A review of randomly selected doubleblind trials found the placebo effect to be generally around 35%.5 TENS certainly is effective in at least one third of patients treated, but the contribution of the placebo effect to this improvement remains a controversial question. Nevertheless, I think that most practitioners would consider this to be a most satisfactory result in dealing with chronic low back pain.
References
1. Long DM. Fifteen years of transcutaneous electrical stimulation for pain control. Stereotact Funct Neurosurg 1991;56:2-19.
2. Sotosky JR, Lindsay SM. Use of TENS in arthritis management. Bull Rheum Dis 1991;40(5):3-5.
3. Langley GB, Sheppeard H. Transcutaneous electrical nerve stimulation (TENS) and its relationship to placebo therapy: a review. NZ Med J 1987;100:215-7.
4. Langley GB, Sheppeard H, Johnson M, Wigley RD. The analgesic effects of transcutaneous electrical nerve stimulation and placebo in chronic pain patients. A doubleblind noncrossover comparison. Rheumatol Int 1984;4:119-23.
5. Shapiro AK. A contribution to a history of the placebo effect. Behav Sci 1960;5:109-35.
Acknowledgement: Dr Merilyn Liddell for providing this information. Editor, Australian Prescriber has published information about fluticasone propionate in its New Drugs section (Aust Prescr 1994;17:74). This stated that caution is advised when changing from the dry powder to the aerosol form of fluticasone; however, clinical trials do not support this statement.1,2
Each inhalation from the metered dose inhaler is half the strength from the corresponding Diskhaler. Therefore, for a given dose, the patient inhales two puffs from the inhaler or the contents of one blister.
Clarification that the devices are clinically equivalent, dose for dose, would be appreciated as this may help to avoid confusion among prescribers regarding the interchangeability of these devices.
Catherine Lewis
Allen & Hanburys
Boronia, Vic.
References
1. Lundback B, Alexander M, Day J, Hebert J, Holzer R, Van Uffelen R, et al. Evaluation of fluticasone propionate (500 mcg/day) administered either as a dry powder via a Diskhaler inhaler or pressurized inhaler and compared with beclomethasone dipropionate (1000 mcg/day) administered by pressurized inhaler. Respir Med 1993;87:609-20.
2. Dahl R. The safety and efficacy of fluticasone propionate 200 mcg daily given via the Diskhaler inhaler as compared with the pressurised metered dose inhaler in adult asthma. Clin Exp Allergy 1993;23(1 Suppl):81S.
The Editor comments:
Caution was advised when the new drug comment was prepared because the bioavailability of the dry powder and the aerosol may be different. The approved product information for fluticasone states 'Doses delivered by the dry powder inhalers and metered dose inhalers may not have the same systemic bioavailability; however, there is no difference in clinical efficacy between the inhalers in controlled studies'.
Examination of the quoted papers reveals that one was a conference presentation and the other was in collaboration with Glaxo Group Research. These shortterm studies (4-6 weeks) showed that each preparation is effective. Although any differences in bioavailability are probably insignificant, neither study had a crossover design to confirm that the formulations are interchangeable. Editor, In Professor Murtagh's article (Aust Prescr 1994;17:33-6), he says 'It is incumbent on the practitioner to provide competent care from the onset with appropriate referrals where necessary so that the patient remains in mainstream medicine and is not tempted to gravitate to alternate practitioners who may confuse management'.
May I ask two questions. Does the training of medical practitioners equip them to provide 'competent care' in this area? Why shouldn't there be interdisciplinary consultation with chiropractors to eliminate confusion of management?
In exactly 50 years I have seen cooperation between doctor and dentist change from virtually nil to full consultation and courteous referral. Surely everyone in their own field should be free to consult and cooperate with others throughout the medical world.
Gordon Hartenstein
Dental Surgeon (retired)
Beverly Hills, N.S.W.
Professor J.E. Murtagh, the author of the article, comments:
Although there is obviously considerable variation in standards within the medical profession, I would expect that most general practitioners are able to provide competent care in the management of back problems. The modern general practitioner is much better educated in this area and several hundred have attended courses on 'Back pain and spinal manipulation' conducted by the Royal Australian College of General Practitioners, the Australian Association of Musculoskeletal Medicine and the Australian College of Physical Medicine. Many are skilled at providing complete care for back problems including use of physical therapies such as spinal mobilisation and manipulation.
If the practitioners lack the skill of physical therapy and other areas of management, they should refer wherever appropriate. However, I am recommending that they should stay in control of management and avoid the situation where patients move completely out of medical management and drift around among alternate practitioners.
This strategy means that general practitioners may cross refer to medical specialists, physiotherapists, osteopaths or chiropractors or any practitioner known to the patient's doctor as a competent caring artisan who is prepared to 'share care'. After all, a successful costeffective outcome to the patient's problem is the primary concern of the general practitioner. Editor, Assessment of a possible drug reaction after dental therapy requires consideration of the type and timing of the reaction, the circumstances under which it occurred and confirmatory testing where possible ('Dental implications' Aust Prescr 1994;17:65). Delayed reactions such as 'burning mouth syndrome', palatal and gingival swelling, perioral dermatitis and recurrent apthous ulceration are well described, and have been attributed to 'Type IV' responses to heavy metals, methacrylate resins and other substances used in amalgams, cements, plates, dental instruments and even mouthwashes.1 Of greater concern are immediate (Type I) allergic responses, resulting in local or systemic reactions. Investigation of patients has previously concentrated on excluding allergic responses to anaesthetic agents or additives and hereditary angioneurotic oedema. The increased use of gloves in medical and dental practice has added another potential allergen to consider: latex. Latex allergy is IgEmediated and, unlike rubberinduced dermatitis (a delayed Type IV reaction), may rapidly precipitate local or generalised urticaria, or even anaphylaxis.2 Conjunctival irritation, nasal congestion and bronchospasm may occur, mediated by airborne latex allergen bound to glove-derived dry powder lubricants.3 Risk factors include atopic status, multiple previous exposures to latex (occupational, as a patient) or previous reactions including glove-related hand dermatitis.2 Confirmatory testing is yet to be standardised; skin testing with 'home-made' latex extracts carries a significant risk of inducing anaphylaxis. 'Hypoallergenic' gloves may still contain allergens; the best prevention is the pretreatment dental or medical history, and use of non-latex products where indicated.4
Raymond J. Mullins
Clinical Immunologist
Newtown, N.S.W.
References
1. Jacobsen N, Hensten-Pettersen A. Occupational health problems and adverse patient reactions in periodontics. J Clin Periodontol 1989;16:428-33.
2. Kelly KJ, Kurup VP, Reijula KE, Fink JN. The diagnosis of natural rubber latex allergy. J Allergy Clin Immunol 1994;93:813-6.
3. Tomazic VJ, Shampaine EL, Lamanna A, Withrow TJ, Adkinson NF Jr, Hamilton RG. Cornstarch powder on latex products is an allergen carrier. J Allergy Clin Immunol 1994;93:751-8.
4. Yunginger JW, Jones RT, Fransway AF, Kelso JM, Warner MA, Hunt LW. Extractable latex allergens and proteins in disposable medical gloves and other rubber products. J Allergy Clin Immunol 1994;93:836-42.
