Letters to the Editor
Treatment of myasthenia gravis
- Andrew Montanari, Dr Stephen Reddel, Jean Foster
- Aust Prescr 2008;31:160
- 1 June 2008
- DOI: 10.18773/austprescr.2008.034
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. When letters are published, they are usually accompanied in the same issue by their responses or comments. The Committee screens out discourteous, inaccurate or libellous statements. The letters are sub-edited before publication. Authors are required to declare any conflicts of interest. The Committee's decision on publication is final.
Editor, – The article on myasthenia gravis (Aust Prescr 2007;30:156-60) made no mention of the role of pseudoephedrine (and perhaps other sympathomimetics), which are most useful in addressing ocular ptosis, when cholinesterase blockers fail.
Although the practice is 'off label', knowing about it can be quite eye-opening, especially for those who rely heavily on the official product information. Non-clinical pharmacists conducting home medication reviews will often query the drug, having no idea why it is being used.
Dr Stephen Reddel, author of the article, comments:
Dr Montanari is quite correct that sympathomimetics including pseudoephedrine offer a mild improvement in myasthenic syndromes, just as adrenergic blockers such as beta blockers have a mildly deleterious effect.
The benefit is rarely enough to be used as monotherapy other than for a cosmetic degree of ptosis, and tends to be short-lived due to tachyphylaxis. Additionally later withdrawal of pseudoephedrine is difficult because of 'fatigue' experienced upon withdrawal, which I think is usually habituation to the central stimulant effects of the drugs, but is easily confused by the patient as a myasthenic symptom. Long-term consequences of pseudoephedrine use, including hypertension, are not insignificant. In my personal practice I reserve the short-term benefit of these drugs for severely ill patients admitted in crisis, when combined with a neostigmine infusion in the intensive care unit, while awaiting the patient's response to other treatments.
Editor, – I would like to congratulate Dr Stephen Reddel on such a well written article (Aust Prescr 2007;30:156-60), probably the most useful piece I have seen on this little known and often overlooked condition.
Readers may be interested to know that in addition to the New South Wales patient support group, there is also a group in Western Australia, which has recently produced the pamphlet outlining which drugs can worsen myasthenia gravis. As some of these drugs can cause potentially life-threatening exacerbations, the pamphlet has been designed to be easy to use in a hurry, so that the treating doctor or dentist can quickly gauge which drugs to use in a particular clinical setting. Copies can be obtained from the association, and the information will soon be available on the website as well (Myasthenia Friends and Support Group,www.myastheniawa.info or telephone (08) 9459 7168). Another Western Australian publication, 'A Handbook for Myasthenics', is available from the association.
Queensland also has a support group: Myasthenia Gravis Association of Queensland (www.mg-qld.gil.com.au).
Salisbury Medical Group
General practitioner, Tamworth, NSW
Salisbury Medical Group, Inglewood, WA