Institut für Pharmakologie und Toxikologie der TUM München
Asthma is a chronic respiratory disease characterised by airways inflammation, constriction of airways smooth
muscles and structural alterations of the airways that may be only partially reversible. Exacerbations of asthma
with impaired expiration leading to dyspnoea (shortness of breath), wheeze, cough and tightness of chest can
develop and may be life-threatening.
Magnesium exerts effects which should be beneficial in the treatment or prophylaxis of asthma. There is a
direct relaxing effect on the smooth muscles of the respiratory tract due to calcium antagonism. Additionally,
the release of bronchoconstricting mediators like acetylcholine and histamine as well as other, probably
inflammatory, compounds will be reduced. Some clinical studies have shown that intravenous magnesium
sulphate may reduce hospital admissions of adults from emergency departments with acute asthma who have
had little or no response to standard treatment. The usual doses in these trials were 1.2 to 2 g MgSO4. In other
studies, no improvements were found, may be because of the lower severity of the diseases.
Various guidelines have been published to inform about the optimal treatment of asthma attacks. Several
include the use of a single bolus of intravenous magnesium sulphate in cases that do not respond to first-line
treatment. However, the effectiveness of this approach remains unclear, particularly in less severe cases.
Administration of magnesium by inhalation is not generally recommended in adults but can be effective in
children. The effectiveness of the therapy with magnesium should be evaluated in further studies. Beside the
studies regarding emergency situations, it seems to be very important to study the effect of magnesium at
magnesium deficiency and in the absence of deficiency on the course of the asthmatic disease.