Most vitamins can be taken with food. B12 is the exception because it is used in microgram amounts...and often lost in food.

Manufacturers which produce combined products usually put the food suggestion on there.

It is best therefore to take a B12 supplement by itself separately so you can control it better, for optimum results.

Nitrous oxide is an inhaled anesthetic used in childbirth and dentristry. It is not injected, but would be inhaled via a mask of some sort.

TIA is transient ischemic attack in the brain... a warning sign of a stroke. Dizziness, numbness, weakness, in a limb or part of the face, is a sign of TIAs. Young women may have strokes when using the hormones in birth control pills. This risk is increased with smoking and in those with genetic tendencies to fast blood clotting.

Vitamins are not likely to cause a stroke. But birth controls pills may.
http://www.strokeassociation.org/STR...3_Article.jsp#