If the medication includes cortisone (as most asthma sprays do), you will have trouble getting it without a prescription. The pharmacy may sell it to you if you promise to bring in a prescription on Monday.

N.B. - For anyone having the same problem in Spain -- it is much less complicated. Almost all medications are available without prescription and, usually, at a fraction of the prices in Germany or the U.S. (My asthma spray costs approx. 12 Euros in Germany, and less than 3 Euros on Tenerife.)