PHARMACOLOGY

 CHANNELS OF DRUG ADMINISTRATION ::

Drugs can be administered upon or into the body on the skin and mucus membrane drugs can be applied to produce localized effects This is local route of administration when drugs are given through mouth (oral route) or by injections (parenteral route) they are absorbed into the blood stream and are distributed throughout the body fluids which travels all over the body such a effect produced by the drug is called systemic effect There are three main routes of drug administration : 1. Local 2. Oral or Enteral and 3.Injectable or parenteral 

LOCAL ROUTE ::;

A drug used locally affects mostly the part it comes in contact with or surrounding and underlying regions However it may also be absorbed from the site of application to the general circulation e.g. cocaine in such cases systemic effects may supervene Drugs are locally administered on the skin and mucus and serous membranes Powder paste lotion liniment cream ointment plaster drops (nasal eye or ear ) etc are generally used on the skin or mucus membranes 

Application of drugs on the skin may be 

(a) Enepidermic :: Simple application of medicament on the skin 

(b) Innunction :: Application of medicament by rubbing 

(c) Iontophoresis :: Iontophoresis is a special method of applying drug to and pushing it through the skin to reach the blood vessels and surrounding deeper tissues by electric transmission The drug is soaked in a wet pad and kept at the site of absorption An electrode having the same polarity as the free drug is kept above it Since the polarity is same in the electrode and the drug the drug ions are repelled and thus the drug enters through the skin In case of arthritis i.e.joint inflammation methyl salicylates are administered by iontophoresis 

(d)  Irradiation :: Rays are also applied to the skin both for local and systemic action e.g. for skin conditions local application of ultraviolet rays and deep X-ray for systemic action 

        Various surfaces of membranes are also subjected to local use In eyes throat ears nose rectum vagina urethra etc drugs can be applied and smeared Through lamellae (eyes) pessaries (vagina) Suppositories (rectum) bougie (urethra) etc drugs can be used locally for long time in years to come insulin will be the drug to be applied as insulin tape to be attached on skin Coronary dilators as drug -tape are already in use