APPENDIX VIII: MAST-CELL STABILIZERS
These drugs have the effect of stabilizing mast cells so that they do not release histamine and other mediators. The main one used is sodium cromoglycate. It is only effective if it reaches the mast cell before the allergen. So it can be used to prevent the symptoms of allergy, as long as the patient remembers to take the drug when they are feeling well, before they encounter the allergen.
The drug is given in inhalers (Intal) as a preventive treatment for asthma. The time from when treatment starts to when the good effects become noticeable is variable – from a few days to several weeks. The drug must be taken continuously to be effective. In some people, it can cause irritation of the throat, coughing or, more rarely, an asthmatic attack. In rare cases there may be a true allergic reaction to the drug. In general, however, sodium cromoglycate is remarkably free of side-effects.
Although the main effect of sodium cromoglycate is to stabilize mast cells, it appears to make the bronchi less reactive in other ways as well. Thus it is used for exercise-induced asthma. Its long-term effect is to make the bronchi less sensitive, which is beneficial.
A related drug, nedocromil sodium (Tilade), is sometimes prescribed instead of sodium cromoglycate for asthma. It acts in much the same way but is a more powerful drug, and is not prescribed for children. Sometimes sodium cromoglycate is combined with other drugs, as in Intal Compound which contains isoprenaline.
In cases of food allergy, taking sodium cromoglycate by mouth (Nalcrom) can block the allergic reaction. But it is only used where the symptoms are not of the immediate-and-violent kind. Thus it might be prescribed for patients with food-induced symptoms such as diarrhoea, asthma, rhinitis, eczema or chronic urticaria, but not for those who suffer swelling of the mouth and tongue on eating a particular food. In such cases, the slight risk of the drug not working has to be considered, because of the serious consequences of such a failure.
To be effective, sodium cromoglycate (taken by mouth) must be taken 10 or 15 minutes before the food is eaten. The beneficial effects of the drug may not appear for several days. Occasionally, the drug may make the symptoms worse, for reasons that are not yet understood, and sometimes it has no effect, or only
partially controls the symptoms. Sometimes patients experience side-effects such as headaches, urticaria, diarrhoea or vomiting.
Because of doubts about its effectiveness if used long-term, simply taking sodium cromoglycate is not the best way to deal with food allergy. Its main use is in patients with reactions to a very wide range of foods, who find it difficult to avoid them all. Even though they are taking the drug, such patients must usually restrict their intake of the main offending foods as well. Babies who react to a wide range of foods on weaning have been helped by sodium cromoglycate.
This drug can also be useful in giving food-allergic people a ‘day off from their restricted diet. Children may be given it for Christmas or birthdays, to allow them to eat normally for a day. Sodium cromoglycate is also used in hay-fever and other forms of allergic rhinitis (Rynacrom) and in allergic conjunctivitis (Opticrom). It can cause stinging when applied but this wears off quickly and again there are no serious side-effects. The drug must be used regularly and consistently for the good effects to be maintained. In Rynacrom Compound, sodium cromoglycate is combined with xylometazoline, a sympathomimetic .
*422\180\8*
