(Aust Prescr 2003;26:75-7)
The Editorial Executive Committee welcomes letters, which should be less than 250 words. Before a decision to publish is made, letters which refer to a published article may be sent to the author for a response. Any letter may be sent to an expert for comment. Letters are usually published together with their responses or comments in the same issue. The Editorial Executive Committee screens out discourteous, inaccurate or libellous statements and sub-edits letters before publication. The Committee's decision on publication is final.
Preparing tranexamic acid 4.8% mouthwash
Editor, – The beneficial haemostatic effect of tranexamic acid 4.8% mouthwash has been demonstrated in oral anticoagulant treated patients undergoing minor oral surgery.1,2However there is no proprietary product readily available to dental practitioners in private practice (Aust Prescr 2002;25:105-6). A practical solution to this problem is the use of Cyclokapron tablets dispersed in water. A crude mouthwash can be prepared by placing a tranexamic acid 500 mg tablet into 10-15 mL of water in a metric measure. The tablet will disperse in approximately 3-5 minutes on standing and quicker with intermittent swirling. Tranexamic acid is readily soluble in water3, however inactive tablet excipients will still be present after adequate mixing. The resulting slurry has little or no taste. Patients should be instructed to swirl the total preparation including the undissolved residue around the mouth for two minutes and then to expel. This is repeated four times a day for up to seven days.1,2Although this method has not been formally validated, sufficient tranexamic acid should be present in the saliva to reduce fibrinolysis.4
Unfortunately the Pharmaceutical Benefits Scheme does not subsidise tranexamic acid 500 mg tablets when prescribed by a dental practitioner. However, they are available as a private dental prescription at a cost of around $31 for a broken pack quantity of 20 tablets. For dental practitioners with no access or assistance from a public teaching hospital this approach partly addresses the issue of having ready access to the mouthwash, although it will not be suitable for all patients.
Fotios Ambados
Specialist Pharmacist, Production Services
The Queen Elizabeth Hospital
Woodville South, SA
References
1. Sindet-Pedersen S, Ramstrom G, Bernvil S, Blomback M. Hemostatic effect of tranexamic acid mouthwash in anticoagulant-treated patients undergoing oral surgery. N Engl J Med 1989;320:840-3.
2. Ramstrom G, Sindet-Pedersen S, Hall G, Blomback M, Alander U. Prevention of postsurgical bleeding in oral surgery using tranexamic acid without dose modification of oral anticoagulants. J Oral Maxillofac Surg 1993;51:1211-6.
3. Windholz M, editor. The Merck index. 10th ed. Rahway, NJ: Merck & Co.; 1983. p. 1368-9.
4. Sindet-Pedersen S. Distribution of tranexamic acid to plasma and saliva after oral administration and mouth rinsing: a pharmacokinetic study. J Clin Pharmacol 1987;27:1005-8.
Editor, – Thank you for the review of asthma therapy delivery devices (Aust Prescr 2003;26:5-7). This article covered important common sense issues in asthma treatment delivery. As suggested by the author, practical issues of use and patient acceptability dominate the decision between a number of otherwise acceptable drug delivery methods. An additional practical issue, in the experience of many Top End practitioners, is that dry powder devices often do not stay dry enough to function in tropical humid conditions, particularly if the users are not very careful to keep the cap screwed on tightly. For this reason dry powder inhalers are not recommended in the Central Australian Rural Practitioners Association Standard Treatment Manual1for use in the tropical Top End.
Dan Ewald
General Practitioner
Lennox Head, NSW
Editor
Standard Treatment Manual for Health Workers, 4th edition.
Reference
1. Central Australian Rural Practitioners Association. Standard treatment manual for health workers. 4th ed. Alice Springs: CARPA; 2003.
Editor, – I wish to draw your attention to some inaccuracy in the new drug comment about Tisseel Duo 500 (Aust Prescr 2003;26:46).
The article commenced by correctly referring to Tisseel Duo 500 with regard to available sizes and approved indications. It then refers to the composition of the 'kit', referring to vials of thrombin, calcium chloride, fibrinolysis inhibitor etc. This description refers to the lyophilised kit form of Tisseel which required reconstitution. The kit was previously available in Australia under the Special Access Scheme of the Therapeutic Goods Administration, until the registered Tisseel Duo 500 became available. This kit was only viable for four hours following reconstitution. It is no longer available in Australia.
Tisseel Duo 500 is deep frozen fibrin sealant, in a preloaded double syringe delivered with the same Duploject device. It does not require reconstitution, only thawing and warming to 37oC. Once thawed, Tisseel Duo 500 is viable for 48 hours. The thawing process requires very little time once removed from the freezer, significantly less than an autologous cryoprecipitate preparation process.
With regards to viral safety, I can state that the previous formulation of the product has been used for 25 years in 50 countries around the world in over 8 million applications resulting in no reported transmissions of HIV, Hepatitis B or C and prion disease. This is due to the donor screening program, the double steam heat treated processing and PCR testing of the product during the manufacturing process.
There are numerous published articles about fibrin sealants available from our Medical Affairs department.
Peter van Gaalen
Bio Surgery Manager
Baxter Healthcare
Toongabbie, NSW
Routine change of intravenous catheters
Editor, – In the article 'Controlling intravascular catheter infections' (Aust Prescr 2003;26:41-3), Table 2 states 'Routinely replace peripheral catheters within 48-72 hours...'.
The Centers for Disease Control in the USA found no evidence to support the routine changing of peripheral venous catheters. The 'Guidelines for the prevention of intravascular catheter-related infections' recommend: 'In adults replace catheter and rotate site no more frequently than every 72-96 hours. Replace catheters inserted under emergency basis and insert a new catheter at a different site within 48 hours. In pediatric patients, do not replace peripheral catheters unless clinically indicated.'1
Hospital bureaucracies frequently mandate routine changing of peripheral catheters within 72 hours, at the cost of great discomfort to patients and effort by resident medical officers. Given that routine changing of central lines has been shown to be unnecessary, and the daily infection risk quoted for peripheral cannulae is much lower than for central lines, it is also implausible that any benefit from routine changing of peripheral lines has been missed.
It would seem beneficial for Australian Prescriber to acquaint its readers with the evidence and discourage them from continuing what seems to be an unnecessary as well as painful custom.
Ian Woodforth
Anaesthetist
Mosman, NSW
Reference
1. MMWR 2002 Aug 16;51:711. Appendix B.
Dr Peter Collignon and Dr Robert Horvath, the authors of the article, comment:
The guidelines of the Centers for Disease Control (CDC) do recommend changes of peripheral lines after 72-96 hours rather than our suggested 48-72 hours. Our concern is that the CDC based the guidelines on the incidence of 'phlebitis', not bacteraemia. As phlebitis is thought to be usually due to non-infective causes (e.g. irritation from drugs), we do not believe it is an appropriate surrogate marker for bacteraemia.
If one examines bacteraemia caused by catheters, it becomes clear that there are almost no cases with catheters that are in place for 24 hours or less and sepsis is very uncommon if the catheters are in place for less than 48 hours.1,2,3The CDC guidelines still recommend routine replacement at 48 hours for 'emergency cannulas'. This is a vague definition and appears to take in our concerns.
In our experience children do not have peripheral cannulas for prolonged periods. Although there is no reason to believe that intravenous catheter sepsis will be different in children, we are unaware of any authority currently recommending routine replacement of peripheral catheters in children.
The problem with doing studies on peripheral catheter sepsis is the very low incidence of bacteraemia (about one episode for every 3000 catheters).4A prospective randomised study would have to be extremely large and is therefore unlikely to be done. However, we believe that the evidence on bacteraemia (rather than phlebitis) strongly suggests that routine replacement of catheters at 48-72 hours will result in lower sepsis rates than replacement at later times.
References
1. Smits H, Freedman LR. Prolonged venous catheterization as a cause of sepsis. N Engl J Med 1967:276:1229-33.
2. Collignon PJ, Sorrell TC, Uther JB. Prevention of sepsis associated with the insertion of intravenous cannulae. The experience in a coronary care unit. Med J Aust 1985;142:346-8.
3. Maki DG, Goldman DA, Rhame FS. Infection control in intravenous therapy. Ann Intern Med 1973;79:867-87.
4. Collignon P. Intravascular catheter associated sepsis: a common problem. The Australian study on intravascular catheter associated sepsis. Med J Aust 1994;161:374-8.
Correcting rheumatoid arthritis
Editor, – I wish to point out an error in 'Disease modifying drugs in adult rheumatoid arthritis' (Aust Prescr 2003;26:36-40). On page 38 the article says sulfasalazine contains acetylsalicylic acid and sulfapyridine. This should be 5-aminosalicylic acid and sulfapyridine.
Josef Tukker
Editor-in-Chief
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