(h) PARENTERAL ADMINISTRATION OF DRUGS:

     Drug for injection may be in glass ampoules Or in glass vials closed with rubber plugs vials in or liquid form or may be in vials in powder form .ln case of drugs which are in vials in powder form they are to be first dissolved in appropriate volume of dissolving fluid which come in ampoules as water for injection. The amount of dissolving fluid to be injected into the vials is explained in the doctor 'prescription Or is mentioned on the vials. 

     All syringes and needles used for injection  must be strike. These days disposable variety of syringes and needles are available. lt is advisable to use disposable syringes and needles and destroy them after use. 

ln case of ampoules. their tips have to be broken after marking with an ampoule cutter which is like small saw or the tip is wrapped in a little cotton and the broken. So that pieces of broken glass may remain the cotton. After fixing the needle to the syringe the medicine in the ampoule is withdrawn in the syringe by pulling out the piston of the syringe slowly

                  In case of medicines in vial. it can be either in liquid form ready form ready for injection Or in powder form which has to be dissolved by injecting the requisite volume of dissolving fluid (water for injection) as explained earlier. 

After fixing the needle on the syringe the requisite volume of the the dissolving fluid (water for injection) is withdrawn in the syringe . The cap of the vial should be cleaned with 70 ०/० spirit and then fluid is injected in the vial. The vial should be cleaned with powder (drug) in the vial. The prescribed volume of the medicine is withdrawn into the syringe by pulling the the piston of the syringe. 

Once the medicine is withdrawn into the syringe it is ready for injection. 

A. INTRA MUSCULAR INJECTION: 

                  For intra muscular injections the sites best suited are (1) The Outside of the. Upper arm in the Deltoid muscle about 6to 70cm below the acromial process of scapula which can be felt subcutaneously: (ii) The upper out quadrant of the gluteal region. Having selected the site the skin of the region is cleaned with spirit (70०/०Alcohol.The skin is rendered tense with the left hand, the syringe containing the medicine and needle attached to it is held in the right hand. Any airbubble inside the syringe is expelled out by slight pressure on the piston of the syringe, and then the needle is inserted obliquely (not vertically as it may hit the bone). A little resistance is felt as the needle pierces the skin and then it goes in smoothly. The needle should go deep into the muscle so that the medicine is not injected in the subcutaneous tissue. When the needle has been inserted to an appropriate depth, the piston of the syringe  is slightly withdrawn to see if any blood inters the syringe. If blood comes into the syringe, it means the needle is in some blood vessel in which case the needle should the pushed below to ensure that it has passed the blood vessel and gone into the muscle. After having ensured that the needle is not in a blood vessel the piston is pressed with the thumb, holding the syringe between the ring and middle finger, till the medicine in the syringe is injected into the muscle. When the medicine has been pushed fully the needle is withdraw and the site of pick is pressed with a cotton with 70% alcohol or sprit.

                          B. Subcuntaneous injection ;

  Certain drugs like insulin and Heparin have to be injected subcutaneously I . e .in the subcutaneous tissue. These drugs usually come in unit-dose sterile packs. sterile syringe and needle has to be used as stated above. In case of insulin special syringe known as "Insulin syringe" is used on which the markings indicate the units of insulin withdraw in the syringe.

        Smaller needles are used for subcuntaneous injection. The sites for injection may be arms, forearms (front), anterior abdominal wall or front of the thigh. The skin over the area selected is first cleaned with swab soaked is sprit or 70% Alcohol. The skin is the pinched between the thumb and index finger and pulled to raise a pinch of skin. The skin is then pinched inserted in the pinched skin so that it goes into the subcuntaneous tissue. Then having insured that the tip of the needle is not a blood vessel the medicine is injected, the needle withdraw and the pick area is pressed with a cotton swap soaked in spirit or 70% Alcohol. 

                       C. Intradermal injection :

    Intradermal injection is given by pushing the needle, keeping it almost horizontal to the forearm front surface just deep to the epidermis and then the prescribed dose of medicine is injected. Example is Montoux test for Tuberculosis.