Dr.U.P.RathnakarDr.U.P.RathnakarMD.DIH.PGDHMMD.DIH.PGDHM

Pharmaceutical processDrug reaches the patientPharmacokinetic processWhat body does to the drugPharmacodynamic processWhat drug does to the bodyPharmacotherapeutic process

Therapeutic effect on the patient

Enteric-coated Tablet

Tablet

Extended-release tablets

Capsules

Mixtures

Injections

Vials

Ampoules

Inhalers Ointments/Creams; Powders

Routes of Drug Administration

Routes of Drug Administration

Route of administration

is the path by which a drug, is brought into contact with the body

Routes of Drug Administration- Classification

A. Local : Topical, Deep tissues, Intra-arterialB. Systemic1. Oral2. Rectal3. S.L.4. Trans Cutaneous5. Injections – s.c, i.m, i.v., intradermal6. Inhalation7. Nasal

Enteral

Parenteral

Local RouteTopical: Local action Ointments, powders, eye drops, paints,

lozenges, unabsorbable drugs, Inhalers for Asthma

Deeper tissues: Intra articular, alveolar block, intrathecal

Intrarterial- Contrast media, cancer therapy

Local Route - EnemaEvacuant enema:- Eg: Soap & water enema , AIM:-to remove faecal matter & flatus

Retention Enema: [Suppositories] Local action:- Eg: Prednisolone enema in

ulcerative colitis.Systemic action[Transrectal]:-MgSO4 to ICT.

Diazepam in epilepsyAdvantages & Disadvantages of

rectal route Vs oral 50% of the drug escapes liver. Embarrassing, Irritation

SublingualDrug placed under the tongue or crushedAdvantages of S/L route- 1.Rapid onset2.Quick termination of the drug effect3.No effect of gastric juice

Disadvantages:- 1.Irritants and non-lipid soluble canot be given

Eg. Nitroglycerine , Buprenorphine, Desaminooxytocin

Oral or Enteral route Advantages :1. Safer2. More convenient3. Economical4. Painless5. Self administration possible6. Complications of parenteral therapy avoided Disadvantages.1. Slow onset2. Irritant & unpalatable drugs can not be given.3. Vomiting, unconscious pts.- not useful4. Drugs which are destroyed by digestive juices -- not

useful.

Tab, Cap, Syp, Enteric coated pills / tablets, Controlled release

PARENTERAL ROUTE s.c, i.m, i.v., intradermal ADVANTAGES1.Unconscious & un-cooperative pt.2.Vomiting & diarrhoea3.Emergencies.4.Irritant drugs (I.V.route)5.Drugs which are destroyed by G.I.

enzymes - given safely.

PARENTERAL ROUTE….DISADVANTAGESLess safeMore expensiveInconvenientSelf medication is difficultPainful.Chances of local tissue injury,& injury to nervesRequires sterilization of instrumentsSkilled

Pressured metered dose aerosols/inhaler- eg.Salbutamol, Beclomethsone.

Oxygen or compressed air driven nebulised solutions- eg. Salbutamol.

Dry powders from inhalers activated by patients inhalation –eg. Salbutamol

Gases eg. General anaesthetics, Oxygen

Inhalation:

LocalAction

SystemicAction

•To prevent dry mouth and hoarseness, rinse mouth after each use. •It is important to practice good oral hygiene to prevent mouth infections•Tooth decay ?

NebulizerMetered dose inhaler

InjectionsIntradermal :

B.C.G Vaccination; Drug sensitivity tests.

Subcutaneous (S.C):Only non-irritant drugs.Insulin; Adrenaline

INTRAMUSCULAR ROUTE : (i.m)Deltoid, Gluteus, Rectus femoris,Mild irritants, suspensionsshould not exceed 10 ml

Intradermal

i.v.injection

IntravenousIntravenous (I.V) route. : Advantages1.100% bioavailability2.Emergencies.3.Large volumes4.Irritant drugs. Eg.- I.V. Nitrogen mustard

Intravenous…DisadvantagesIts action cannot be haltedLocal irritation can lead to phlebitisSelf medication is difficult.Requires sterilization of instruments.Precautions: Should be given slowly. Ensure that the needle is in the vein.

Alveolar Blocks

TranscutaneousIontophoresis: Galvanic current eg:salicylates.

Jet injections:- High velocity jetNo needle –painlessSuitable for mass inoculation. Jet injections for insulin also available.

TRANSDERMAL DRUG DELIVERY SYSTEMTransdermal therapeutic system[TTS]

Eg.Scopolamine, Nitroglyserine, Nicotine.

Trans-nasal route

Postpituitary extract in Diabetes insipidus.

GnRH, & Calcitonin [Nasal decongestant-Topical]

Factors deciding the choice of routePhysical & chemical properties-

Solid/Liquid/Gas, Irritancy, pHSite of desired action- Local or

systemicRate of absorption from a routeEffect digestive juice and First pass

metabolismRoutine or emergencyAccuracy of dosageCondition of Pt.-Unconcious, vomiting