This article is from the Asthma FAQ, by Patricia Wrean and Marie Goldenberg email@example.com with numerous contributions by others.
The combination drugs such as Tedral and Marax commonly
contain theophylline, ephedrine, and some form of sedative
such as phenobarbital. These combination pills are no longer
commonly prescribed because the amount of theophylline in
the pill cannot be varied with respect to the other drugs.
Since there is great variation in the rate at which an
individual metabolizes theophylline, it is now considered
better to take theophylline separately, for better adjustment
of theophylline levels. In fact, Tedral is no longer
manufactured by Parke-Davis in the U.S.
Also, ephedrine is no longer considered the bronchodilator
of choice. From Drs. Haas, _The Essential Asthma Book_,
"ephedrine initiates the release of catecholamines -- including
adrenaline -- that are already stored in the body. This is
its biggest drawback. Its effects depend on the availability
of catecholamine in the body at the time it is given, and
these concentrations vary." Since much better bronchodilators
are now available, ephedrine is no longer commonly prescribed.