Tuesday, 27 March 2007

Influenza and Asthma!

This week was supposed to be my Winter Holiday, and my family and I had arranged to go travelling in Japan.

However, my whole family developed an Influenzal-like illness thereby putting an end to any travelling !

My son saw a doctor who diagnosed an infective viral exacerbation of asthma and gave him nebulised beta agonist and theophylline powder and my wife was told something like-- 'don't use the inhaler' (albuterol beta-agonist metred dose inhaler from the USA)......without being given any explanation why she should stop.....

This left me confused as it was against all the UK medical training and evidence I had come to know.

I am not a paediatrician, but this did not sound at all right to me, so I have investigated further.

So, on checking UpToDate for childhood asthma, it confirmed that Mild Acute Asthma should firstly be treated with beta-stimulant either via a nebuliser or metered inhaler via a spacer (as was done) and following this, an inhaled steroid should be provided too.

In the UK British Thoracic Society November 2005 guidance for asthma (some 98 pages !!), no where in the acute guidance does Theophylline feature apart from when all else fails in severe acute asthma !!

In fact, moderate to severe asthma suggests substituting inhaled corticosteroid for intravenous steroid, adding ipratropium, and failing that, to give intravenous magnesium or iv beta stimulant (salbutamol / albuterol).

As for adults with acute asthma, theophylline does not show any more improvement in acute asthma than the combined use of beta-stimulant, ipratropium and steroid administration.

I have heard of cases where patients at local clinics have been given iv aminophylline as a primary treatment in acute asthma and then sent to our hospital when they should have been given a beta-stimulant nebuliser and steroids. This kind of therapy is clearly against the current evidence base.

The main place for aminophylline is in chronic respiratory conditions such as childhood chronic asthma, COPD or in patients who are unable to use an inhaler or have poor compliance.

In such cases of chronic asthma, there is evidence that combined with beta-stimulant and steroid, there is better control of asthma symptoms. Here again though, it should not be given in place of beta-agonist or inhaled corticosteroids but rather compliments their beneficial effects. In this setting, aminophylline can allow the reduction of steroid dose and frequency of beta-stimulant use (UpToDate 15.1)

I appreciate that the Japanese Guidelines advocate aminophylline as a second line agent but as far as I am aware, they have not been updated recently.

Aminophylline is a cheap drug and has alot of physiological effects such as bronchodilatation, anti-inflammatory effects and anti-chemotaxic effects against eosinophils, but obtaining therapeutic levels may be problematic and patients already on oral preparations or who drink coffee can develop toxicity which includes: tachycardia, tremor, seizure (<1%),> In such patients, IV preparations should be avoided to prevent such toxicity.

The treatment of acute asthma in the UK and USA is certainly different compared to what I have seen in Japan.

The UK Guidance can be viewed here: http://www.brit-thoracic.org.uk/iqs/sid.08626940972447923509053/
Guidelinessince%201997_asthma_html (PLEASE CUT AND PASTE TO GO TO THE SITE)

The UK guidelines only institute IV aminophylline in the acute setting when nothing else works and patients are in intensive care (adults) or Pediatric ICU (PICU) but certainly not in place of other measures mentioned above.

Please consider before using this drug.

Do you have extensive experience in the use of this drug and agree or disagree with the above blog? If so, please leave a reply as this is an open forum (albeit moderated) and your opinions would be helpful for other junior doctors to learn.

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