Effects of dixyrazine and methaqualone on the sleep pattern in normal man.

Whole night EEG and polygraphic recordings were made in ten young, healthy, male volunteers after dixyrazine (12.5 mg, 25 mg, 50 mg), methaqualone (250 mg) and Isonox (methaqualone 250 mg + etodroxizine 50 mg). A total of 156 recording nights (36 adaptation nights were not included in the analyses) were scored for different sleep stages according to accepted criteria. The smallest dose of dixyrazine (12.5 mg) had no significant effect upon sleep pattern: the larger doses (25 mg and 50 mg) caused significant decreases in REM-sleep during the first nights of administration. The decrease disappeared during the following two nights of treatment. No withdrawal effects were seen. Methaqualone also caused moderate depression of REM-sleep during the first night of treatment, and this effect, too, disappeared during prolonged administration. Isonox (methaqualone + etodroxizine) had a somewhat stronger surpressive effect upon REM-sleep than methaqualone alone.