A tablet showing regulated variation in dissolution from lot to lot which contains from about 3 to about 50% by weight (w/w), based on the whole tablet, of (S)—N-[2-(1,6,7,8-tetrahydro-2H-indeno[5,4-b]furan-8-yl)ethyl]propionamide, magnesium stearate and hydroxypropylcellulose having a viscosity of about 1 to about 4 mPa·s.