Parenteral products
These are sterile preparations containing one or more active ingredients intended for administration by injection, infusion or implantation into the body.
Injections:
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.
Disadvantages:
• 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:
Intradermal injections:
• 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.
Subcutaneous injections:
• 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.
Intramuscular 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.
Intravenous 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.
Intracardiac route:
• These are given into the heart muscles or ventricle only in emergency.
• E.g. A stimulant in case of cardiac arrest
Intrathecal route:
• These are given into the subarachnoid space that surrounds the spinal cord.
Intra – articular route:
• These are given directly into the joints.
Intracerebral route:
• These are given into the cerebrum.
