Mast cells. Mast cells and basophils are generally thought to be the major sources of histamine and can themselves be modulated by histamine as they express H 1, H 2 and H 4 receptors, although how this varies between different mast-cell types is not yet clear.
3. The pill is to be taken soon after unprotected sex. It should be taken preferably within 24 hours and before 72 hours or else the pill may turn useless. 4. I-pill checks pregnancy by preventing ovulation or fertilisation or implantation of the fertilised egg. 5. I-pill is 95 per cent effective if taken in time.
It is important to be aware that Levonelle must be taken within 72 hours of unprotected sex, and ellaOne within 120 hours. However, they are both most effective taken as soon as possible after sex. Depending on your circumstances, you might want to buy the morning after pill for immediate use or future use.