The baseline value for FEVi and the maximum percentage of change in FEVi after drug administration and after exercise are shown in Table 2. The FEVi measured before each study was very similar in each of the subjects. There was no change in FEVi after inhalation of placebo (mean changes, —0.2 percent). After inhalation of 20 mg of disodium cromoglycate, one patient (patient 6) developed acute bronchoconstriction, and the FEVi dropped by 55 percent; spontaneous recovery occurred within 30 minutes when the exercise test was performed. The remaining patients showed no change in the FEVi after administration of disodium cromoglycate. Administration of 80/xg of Sch 1000 produced a mild degree of broncho-dilation; the mean change in FEVi was 4-8 percent.
The mean maximum reduction in FEVi after exercise was 36 percent. The administration of placebo before exercise did not prevent exercise-induced asthma; the mean maximum reduction in FEVi was 34 percent; however, in one patient (patient 2), administration of the placebo may have given some degree of protection; the maximum reduction in FEVi was 22 percent, instead of 52 percent when the exercise test was performed without any drug therapy. How do athletes cope with asthma? Click here to find out.
When disodium cromoglycate was given before exercise, the mean maximum reduction in FEVi was 15 percent Administration of disodium cromoglycate offered almost complete protection in five patients (patients 1, 3, 4, 7, and 8), partial protection in two patients (patients 2 and 9), and no protection in two patients (patients 5 and 6).
When Sch 1000 was administered before exercise, the mean maximum reduction in FEVi was 10 percent. Inhalation of Sch 1000 rendered complete protection in six patients (patients 1, 3 to 5, 7, and 8), partial protection in two patients (patients 6 and 9), and no protection in one patient (patient 2).
In six patients, disodium cromoglycate and Sch 1000 were both effective in preventing exercise-induced asthma (Fig 1). In two patients (patients 5 and 6), administration of Sch 1000 was effective, while inhalation of disodium cromoglycate gave no protection (Fig 2); in the remaining patient (patient 2), disodium cromoglycate was more effective than Sch 1000.
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Figure 1. Exercise-induced asthma in patient 4. Administration of disodium cromoglycate (DSCG) and Sch 1000 before exercise prevented exercise-induced asthma. Administration of placebo gave no protection.
Figure 2. Exercise-induced asthma in patient 5. Administration of Sch 1000 before exercise prevented exercise-induced asthma, while disodium cromoglycate (DSCG) and placebo were ineffective.
Table 2—Baseline FEV\ and Maximum Percent Change in FEV\ after Administration of Drugs and after Exercise
| No Drug | Placeboл | Disodium Cromoglycate | Sch 1000A | ||||||||
| Patient | B | E | rB | A | E | B | A | E | r—-B | A | E |
| 1 | 3.60 | -22 | 3.33 | 0 | -39 | 3.66 | 0 | 2 | 3.25 | 8 | 5 |
| 2 | 3.02 | -52 | 3.07 | 0 | -22 | 2.94 | – 1 | -12 | 2.62 | 11 | -60 |
| 3 | 3.96 | -39 | 3.56 | – 3 | -26 | 3.97 | 1 | – 9 | 4.19 | 4 | 0 |
| 4 | 2.18 | -36 | 2.40 | 4 | -41 | 2.22 | – 4 | 0 | 2.36 | 13 | 8 |
| 5 | 3.07 | -28 | 3.11 | – 4 | -27 | 3.26 | 0 | -22 | 3.02 | 9 | – 4 |
| 6 | 2.63 | -50 | 2.45 | 8 | -59 | 2.45 | -55 | -65 | 2.67 | 7 | -12 |
| 7 | 3.25 | -25 | 3.25 | 0 | -25 | 2.98 | 0 | – 7 | 2.80 | 3 | – 8 |
| 8 | 2.50 | -17 | 2.80 | – 6 | -17 | 2.54 | – 4 | – 3 | 2.54 | 10 | 14 |
| 9 4.27 Mean ± SD | -58 | 4.55 | – 1 | -51 | 4.40 | 0 | -14 | 4.55 | 3 | -30 | |
| 3.16±0.68 -36±15 | 3.16 ±0.64 | -0.2 ±4 | -34 ±14 | 3.16 ±0.73 – | *7±18 | -15 ±22 | 3.11 ±0.76 | 8±4 | -10 ±23 | ||