The use of calcium(2000mg per day) and magnesium(1000mg per day)was reported
anecdotally as a treatment for nipple vasospasm in Mayer SM "An overview of
Solutions to Breastfeeding Problems" La Leche League 1988. I haven't found
it particularly useful. I have had more success with using
Nifedipine(tablets 5-10mg 2-3x per day,the tablet form is mid range active,
or the long acting form:called Adalat Oros in Australia,30mgs per
day)Nifedipine is highly protein bound and so is found in only trace amounts
in breastmilk.Most women tolerate it well. Recent concerns about the safety
of Nifedipine in patients with cardiovascular disease have been raised in a
meta-analysis by Furberg et al 1995 "Nifedipine: dose related increase in
mortality in patients with coronary heart disease".Circulation 92:
1326-1331.The significance of this study has been seriously questioned in
two subsequent review articles(Opie and Messerli 1995 Circulation 92
;1068-1973 and Kloner 1995 Circulation 92:1074-1078). Increased mortality in
Furberg's study was seen in patients taking high doses (80 mg) of short
acting Nifedipine capsules. For this reason, it would seem prudent until
this controversy is resolved to use slow release Nifedipine,or mid range
active tablets, or if short acting Nifedipine is required to use it in doses
of less than 80 mg.  Carolyn Lawlor-Smith GP/LC South Australia