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. 1  Introduction. 2  Niacin, also known as nicotinic acid and vitamin B3, is a water soluble, essential B vitamin which, when given in high doses, is effective in lowering low density lipoprotein (LDL) cholesterol and raising high density lipoprotein (HDL) cholesterol, which makes this agent of unique value in the therapy of dyslipidemia.