The majority of pregnant women do not complain of morning sickness until the 6th week of pregnancy, 2 weeks after a missed period. But for some women, that nagging feeling can start as early as one week after conception, a full week before a missed period. Changes in hormones account for the queasiness that occurs.
DRUG CLASS AND MECHANISM: Niacin (nicotinic acid, vitamin B3) is a part of the normal diet that is essential to various chemical reactions in the body.
Niacin is a water-soluble B vitamin vitamin B3 - and the common name for 2 very different compounds: nicotinic acid and niacinamide. High doses of niacin (as nicotinic acid) can lower cholesterol levels (although the exact mechanism of action is still not known).owever, niacin is also made in the form of niacinamide-a form of vitamin B3 which, deliberately, is manufactured so that it will NOT cause dilation of the blood vessels-the flush so well known when using plain niacin.