quinine sulfate + theophylline

The drug **quinine sulfate + theophylline** is a fixed-dose combination of quinine sulfate, an antimalarial and muscle relaxant alkaloid, and theophylline, a methylxanthine bronchodilator often used for asthma and COPD. This combination has been clinically studied, especially in Europe, for the treatment of **nocturnal leg cramps**. Quinine acts primarily by inhibiting muscle excitability and interfering with neuromuscular transmission, while theophylline enhances cAMP production by inhibiting phosphodiesterase, possibly potentiating the effect of quinine on skeletal muscle. In clinical studies, the combination was found to be significantly more effective in reducing frequency and severity of nocturnal cramps than quinine alone, without increased risk of serious adverse events[1][4].

Other names

quinine + theophylline ethylenediamine