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.
Take emergency contraception as soon as possible. If youâve had unprotected sex and are concerned that you could get pregnant, take the morning after pill, which is also called emergency contraception, as soon as you can.In most cases, you can take the morning after pill up to five days following unprotected sex. The morning after pill may not have any cost, or a clinic may price it on a sliding scale for those that can't afford full price. 2  You will be asked about your income and insurance to determine your fee. 3  Most universities have a health center that may offer emergency contraception.