yuaband was recently diagnoised with parkinsons and was prescrined trihexypheniayl for his shakey hands amd head and his ridgidity of his neck muscles ....he took 1/2 tablet for 2 weeks three times a day. then he had to start to take 1 whole tablet three times a day and he is experienceimg dizziness when he bends over and stands back up is this normal? only been on the med for two weeks and rwo days. was having same effects with only half a pill so the increase did not cause the dizziness.