These are sterile preparations containing one or more active ingredients intended for administration by injection, infusion or implantation into the body.
These are sterile solutions or suspensions of drugs in aqueous or oily vehicle meant for administration into the body by means of a needle under or through one or more layers of skin.
Advantages of parenteral:
• Onset of action is fast.
• Drug can be given to unconscious patient.
• Drug action can be prolonged by modifying the formulation.
• Bioavailability is high.
• Free from first pass metabolism.
• Drugs which cannot be given orally, can be given by parenteral route.
• Used in emergency situation.
• It requires trained person for injecting the drug solution.
• It can cause pain and inflammation.
• Drug withdrawl is not possible.
• It is costly.
• There are chances of tissue damage.
• It may cause infection at site of injection.
• It may cause sepsis.
• It may cause thrombophlebitis.
• It may cause fluid overload.
• Disposal of needles, syringes or other infusion devices required extra efforts.
Routes of administration:
• These are given between the layers of skin.
• Skin of left forearm is selected for this injection.
• 0.1– 0.2 ml is given by this route.
• Diagnostic agents are given by this route.
• 25 – 26 gauge needle is used.
• These are given under the skin, into the subcutaneous tissues.
• 1ml or less volume is given by this route.
• Injection is given into upper arm.
• Most convenient route.
• Solutions, emulsions and suspension are given by this route.
• These injections are given into the muscular tissues.
• The muscles of the shoulder, thigh or buttock are selected for this injection.
• Volume upto 2ml can be given by this route.
• Aqueous or oily suspensions are given by this route.
• These injections are given into the vein and hence drug directly reaches to the blood.
• Volume from 1ml to 1000ml can be given by this route.
• 19 – 20 gauge needle should be used.
• IV infusion of large volume parenteral is called Venoclysis and it is used to give electrolyte and nutrients.
• Suspension and oily injections cannot be given by this route.
Intra- arterial route:
• These injections are directly given into the artery.
• It requires generally surgery.
• These are given into the heart muscles or ventricle only in emergency.
• E.g. A stimulant in case of cardiac arrest
• These are given into the subarachnoid space that surrounds the spinal cord.
Intra – articular route:
• These are given directly into the joints.
• These are given into the cerebrum.