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![Condition of Patient (Acute or Chronic)
In an acute or emergency situation, the route used must allow sufficiently fast
absorption to ensure a prompt onset of action.
Route of Choice in
Acute Condition
Parenteral Injection
(I.V., I.M., S.C.)
Intrathecal route
(for amphotericin B
in cryptococcal
meningitis)
Inhalation Route (for
bronchodilators [by
nebulizer] in acute
bronchial asthma attack)
Sublingual Route (for
nitroglycerin in acute
angina attack)
With young children, the rectal route (as enema or suppository) may also be used,
especially when the patient is unconscious or when vomiting occurs.](https://image.slidesharecdn.com/routesofadministration-190206074844/75/Routes-of-administration-4-2048.jpg)
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Routes of administration
- 1. KNOW ABOUT YOURDRUGS PART - II PRESENTED BY SANI SINGH M. PHARM (PHARMACEUTICS) Route of Drug Administration
- 2. Drugs canbe administered by different routes for their suitability, efficacy, rapid action, and patient condition. When making decision on the route of administration, two major factors come to mind: therapeutic concerns and drug properties. Therapeutic Concerns include questions relating to the desired onset rate and duration of drug action, where the drug target site is (readily accessible or not) and whether or not patient compliance is an issue. Drug Properties to be taken into account include its physicochemical characteristics (e.g., lipid solubility, molecular size, ionization status) and plasma concentration-time profile. Selection of Route for Administration
- 3. Factors Characteristics of the drug Emergency/routine use Effectof gastric pH, digestive enzymes and first- pass metabolism Age of patient Site of action of the drug (local or systemic) Condition of the patient (unconscious, vomiting, diarrhea). Factors Consider for Route of Administration
- 4. Condition of Patient(Acute or Chronic) In an acute or emergency situation, the route used must allow sufficiently fast absorption to ensure a prompt onset of action. Route of Choice in Acute Condition Parenteral Injection (I.V., I.M., S.C.) Intrathecal route (for amphotericin B in cryptococcal meningitis) Inhalation Route (for bronchodilators [by nebulizer] in acute bronchial asthma attack) Sublingual Route (for nitroglycerin in acute angina attack) With young children, the rectal route (as enema or suppository) may also be used, especially when the patient is unconscious or when vomiting occurs.
- 5. For thetreatment of chronic illnesses, the onset rate is not so much of a concern, whereas a more convenient route (e.g., oral, transdermal or topical) and simple dosing regimen (e.g., once-daily or once weekly dosing) would ensure better patient compliance. Formulation that can provide controlled release of the drug would be an added advantage especially in situation of poor patient compliance (e.g., severe depression). That is notwithstanding the need to take into account the cost factor. Route of Choice in Chronic Condition Oral Route Topical RouteTransdermal Route
- 6. Different Route ofAdministration Route for administration Time until effect Intravenous 30-60 seconds Intraosseous 30-60 seconds Intramuscular 10-20 minutes Endotracheal 2-3 minutes Subcutaneous 15-30 minutes Inhalation 2-3 minutes Sublingual 3-5 minutes Transdermal (topical) Variable (minutes to hours) Rectal 5-30 minutes Ingestion 30-90 minutes
- 7. Routes of Administration LocalSystemic • Intra-arterial route • Deeper Tissues • Topical EnteralParenteral • Oral • Sublingual/Buccal • RectalInjections • Intradermal • Subcutaneous • Intramuscular • Intravenous • Intraperitoneal • Intramedullary TransdermalInhalation
- 8. Local Routes Itis the simplest mode of administration of a drug at the site where the desired action is required. Systemic side effects are minimal. 1. Intra-arterial route • This route is rarely employed. It is mainly used during diagnostic studies such as coronary angiography and for the administration of some anticancer drugs, e.g. for treatment of malignancy involving limbs.
- 9. Intra-articular Injection Intrathecal Injection Retrobulbar Injection 2. Administration ofthe Drug into Deep Tissues Deep areas can be approached by using a syringe and needle, but the drug should be such that systemic absorption is slow. Intra-articular injection - Drug is injected into the subarachnoid space (spinal anaesthetics, e.g. lignocaine; antibiotics, e.g. amphotericin B, etc.). Intrathecal Injection - Drug is injected directly into the joint space, e.g. hydrocortisone injection for rheumatoid arthritis. Strict aseptic precautions should be taken. Repeated administration may cause damage to the articular cartilage.
- 10. 3. Topical • Suspension(Nystatin) • Troche (Clotrimazole - for oral candidiasis) • Cream (Acyclovir - for herpes labialis) • Ointment and Jelly (5% Lignocaine hydrochloride - for topical anaesthesia) • Spray (10% Lignocaine hydrochloride - for topical anaesthesia) Oral Cavity • Tablet that is not absorbed (neomycin – for sterilization of gut before surgery) GI Tract • An enema (administration of drug into the rectum in liquid form) e.g. soap water • Suppository (administration of the drug in a solid form into the rectum) e.g. bisacodyl Rectal and Anal • Drops, ointments and sprays (for infection, allergic conditions, etc.) e.g. gentamicin eye/ear drops. Eye, Ear and Nose • Inhalation, e.g. salbutamol, ipratropium bromide, etc. (for bronchial asthma and chronic obstructive pulmonary disease).Bronchi • Ointment, cream, lotion or powder, e.g. clotrimazole (antifungal) for cutaneous candidiasis.Skin
- 11. Systemic Routes Drugsadministered by this route enter blood and produce systemic effects. Medication, nutrition or other substances into the circulatory system so that the entire body is affected. It classify 2 broad categories like Enteral (oral, sublingual, and rectal) and Parenteral (inhalation, injection, transdermal) routes.
- 12. 1. Oral Route It is the most common and acceptable route for drug administration. Dosage forms are tablet, capsule, syrup, mixture, etc., e.g., paracetamol tablet for fever, omeprazole capsule for peptic ulcer are given orally. Advantages Shafer Cheaper Painless Convenient for repeated and prolonged use Can be self- administered Disadvantages Not suitable for emergency as onset of action of orally administered drugs is slow It is not suitable for/in: Unpalatable and highly irritant drugs Unabsorbable drugs (e.g. aminoglycosides) Drugs that are destroyed by digestive juices (e.g. insulin) Drugs with extensive first-pass metabolism (e.g. lignocaine) Unconscious patients Uncooperative and unreliable patients Patients with severe vomiting and diarrhoea
- 13. 2. Sublingual/Buccal Route The preparation is kept under the tongue. The drug is absorbed through the buccal mucous membrane and enters the systemic circulation directly, e.g. nitroglycerin for acute anginal attack and buprenorphine for myocardial infarction. Advantages Quick onset of action. Action can be terminated by spitting out the tablet. Bypasses first-pass metabolism Self-administration is possible. Disadvantages It is not suitable for: Irritant and lipid-insoluble drugs. Drugs with bad smell and taste.
- 14. 3. Rectal Route Drugs can be given in the form of solid or liquid. a. Suppository: It can be used for local (topical) effect as well as systemic effect, e.g. indomethacin for rheumatoid arthritis. b. Enema: Retention enema can be used for local effect as well as systemic effect. The drug is absorbed through rectal mucous membrane and produces systemic effect, e.g. diazepam for status epilepticus in children. • Useful in the patient ishaving recurrent vomiting or unconscious stage. • Potential of long term drug absorption with various intrauterinedevices (IUDs). • Some irritant and unpleasant drugs can be introduced into rectum as suppositories. Advantages • This is rather inconvenient and embarrassing. • Absorption is slower, irregular and unpredictable. • Bleeding problems such as discomfort to real pathologies. Disadvantages
- 15. Parenteral Routes Routesof administration other than enteral route are called parenteral routes. • Onset of action of drugs is faster; hence it is suitable for emergency. • Useful in: Unconscious, Uncooperative and unreliable patients. • It is suitable for: Irritant drugs, Drugs with high first-pass metabolism, Drugs not absorbed orally, Drugs destroyed by digestive juices. Advantages • Preparations should be sterile and is expensive. • Requires invasive techniques that are painful. • Cannot be usually self-administered. • Can cause local tissue injury to nerves, vessels etc. • Require aseptic conditions. Disadvantages
- 16. 1. Inhalation Drugs whichare gaseous (e.g., nitrous oxide) or readily vaporized (e.g., isoflurane) may be inhaled. Solid drugs may also be given by inhalation route in the form of aerosols or suspended powder (e.g., salbutamol and beclomethasone). The inhalation route may be used for producing both local (e.g., bronchodilatation in asthma) as well as systemic effects (anesthesia). Advantages • Quick onset of action. • Dose required is very less, so systemic toxicity is minimized. • Amount of drug administered can be regulated. Disadvantages • Local irritation may cause increased respiratory secretions and bronchospasm. Advancements Nebulizer Metered Dose Inhaler (MDI) Powder Inhaler (DPI)
- 17. 2. Injections Injectable Routesof Drug Administration
- 18. The drugis injected into the layers of the skin, e.g. Bacillus Calmette–Guerin (BCG) vaccination and drug sensitivity tests. It is painful and only a small amount of the drug can be administered. Intradermal injectionalso known as the mantoux method. Purpose : Injects medication below the epidermis drugs are absorbed slowly. Typically used for diagnosis of tuberculosis and allergens. a. Intradermal Route Methods of Intradermal Injections Normal Size Needle Shorter Needle Without Needle
- 19. b. Subcutaneous Route(s.c.) The drug is injected into the subcutaneous tissues of the thigh, abdomen and arm, e.g. adrenaline, insulin, etc. Only small amount can be injected S.C self injection is possible because deep penetration in not needed Advantages • Self-administration is possible (e.g. insulin). • Depot preparations can be inserted into the subcutaneous tissue, e.g. norplant for contraception. Disadvantages • It is suitable only for nonirritant drugs. • Drug absorption is slow; hence it is not suitable for emergency.
- 20. Advancement in SubcutaneousRoute Dermojet • A high velocity jet of drug solution is projected from a microfine orifice using a gun like implement. • The solution passes through the superficial layers and gets deposited in the subcutaneous tissue. Pellet implantation • The drug in the form of a solid pellet is introduced with a trochar and cannula. • This provides sustained release of the drug over weeks and months e.g. DOCA, testosterone. Sialistic (nonbiodegradable) and biodegradable implants • Crystalline drug is packed in tubes or capsules made of suitable materials and implanted under the skin. • Slow and uniform leaching of the drug occurs over months providing constant blood levels. • The nonbiodegradable implant has to be removed later on but not the biodegradable one. • Examples - for hormones and contraceptives (e.g. NoRPLANT).
- 21. c. Intramuscular Route(I.M.) Drugs are injected into large muscles such as deltoid, gluteus maximus and vastus lateralis, e.g. paracetamol, diclofenac, etc. A volume of 5–10 mL can be given at a time. Advantages Disadvantages • Absorption is more rapid as compared to oral route. • Mild irritants, depot injections, soluble substances and suspensions can be given by this route. • Aseptic conditions are needed. • Intramuscular injections are painful and may cause abscess. • Self-administration is not possible. • There may be injury to the nerves.
- 22. d. Intravenous Route(i.v.) Injection into a peripheral vein over 1 to 2 minutes (bolus) or longer as an infusion. Drugs are injected directly into the blood stream through a vein. Drugs are administered as: 1. Bolus: Single, relatively large dose of a drug injected rapidly or slowly as a single unit into a vein. For example, i.v. ranitidine in bleeding peptic ulcer. 2. Intravenous infusion: For example, dopamine infusion in cardiogenic shock; mannitol infusion in cerebral oedema; fluids infused intravenously in dehydration. 3. Slow intravenous injection: For example, i.v. morphine in myocardial infarction.
- 23. Advantages • Bioavailability is100%. • Quick onset of action; therefore, it is the route of choice in emergency. • Large volume of fluid can be administered, e.g. intravenous fluids in patients with severe dehydration. • Highly irritant drugs, e.g. anticancer drugs can be given because they get diluted in blood. • Hypertonic solution can be infused by intravenous route, e.g. 20% mannitol in cerebral oedema. Disadvantages • Local irritation may cause phlebitis. • Self-medication is not possible. • Once the drug is injected, its action cannot be halted. • Strict aseptic conditions are needed. • Extravasation of some drugs can cause injury, necrosis and sloughing of tissues. • Depot preparations cannot be given by i.v. route. Precautions - Drug injected slowly and before injecting, make sure that the tip of the needle is in the vein.
- 24. 3. Transdermal Route The drug is administered in the form of a patch or ointment that delivers the drug into the circulation for systemic effect . For example, scopolamine patch for sialorrhoea and motion sickness, nitroglycerin patch/ointment for angina, oestrogen patch for hormone replacement therapy (HRT).
- 25. Advantages • Self-administration ispossible • Prolonged duration of action • Minimize systemic side effects • Provide a constant plasma concentration of the drug • Patient compliance is better Disadvantages • Expensive • Local irritation may cause itching and dermatitis • Patch may fall-off unnoticed • Drug must be lipophilic in nature
- 26. Absorption Pattern, Advantagesand Disadvantages of the Most Common Routes of Administration Route of Administration Absorption Pattern Advantages Disadvantages Oral Variable; affected by many factors • Safest, economic and most common route • Food may affect absorption • Drug may be metabolized before systemic absorption Intravenous Absorption not required • Suitable for irritating substances and complex mixtures • Dosage titration permissible • Ideal for high molecular weight proteins and peptide drugs • Unsuitable for oily substances • Bolus injection may result in adverse effects • Strict aseptic techniques needed Subcutaneous • Depends on drug diluents: Aqueous solution: prompt Depot preparations: slow and sustained • Suitable for slow-release drugs • Ideal for some poorly soluble suspensions • Pain or necrosis if drug is irritating • Unsuitable for drugs administered in large volumes
- 27. Route of Administration Absorption PatternAdvantages Disadvantages Intramuscular • Depends on drug diluents: Aqueous solution: prompt Depot preparations: slow and sustained • Suitable for oily vehicles and certain irritating substances • Preferable to intravenous if patient must self administer • Affects certain lab tests (creatine kinase) • Can cause intramuscular hemorrhage (precluded during anticoagulation therapy) Transdermal (Patch) Slow and sustained • Ideal for drugs that are lipophilic and have poor oral bioavailability • Ideal for drugs that are quickly eliminated from the body • May cause delayed delivery of drug to pharmacological site of action • Limited to drugs that can be taken in small daily doses Rectal Erratic and variable • Bypasses destruction by stomach acid • Ideal if drug causes vomiting • Ideal in patients who are vomiting, or comatose • Drugs may irritate the rectal mucosa • Not a well-accepted route
- 28. Route of Administration Absorption PatternAdvantages Disadvantages Inhalation Systemic absorption may occur; this is not always desirable • Ideal for gases • Effective for patients with respiratory problems • Localized effect to target lungs: lower doses used compared to that with oral or parenteral administration • Most addictive route (drug can enter the brain quickly) • Patient may have difficulty regulating dose Sublingual Depends on the drug: Few drugs (example, nitroglycerin) have rapid, direct systemic absorption Most drugs erratically or incompletely absorbed • Bypasses destruction by stomach acid • Drug stability maintained because the pH of saliva relatively neutral • May cause immediate pharmacological effects • Limited to drugs that can be taken in small doses • May lose part of the drug dose if swallowed
- 29. Route of Administration Dosage Form OralSolution, Syrups. Suspensions, Emulsions, Gels, Powders, Granules, Capsules, Tablets Parenteral Injections (solutions, suspensions, Emusions forms) implants, irrigation & dialysis solutions Topical Ointment, Creams, Pastes, Lotions, Gels, Topical Aerosols, Transdermal patches Rectal Suppositories, Ointments, Creams, Powders, Solutions Respiratory Aerosol (solustions suspensions, emulsions, powders forms) inhalations, sprays, gases Nasal Solutions, inhalations Ear Solutions, Suspensions, ointments, creams Eye Solutions, ointments, creams
- 30. • For adrug to be clinically useful, it must also have an appropriate pharmacokinetic profile besides having the desired pharmacodynamic action. • The choice of the route of drug administration depends mainly on two major factors: therapeutic concerns and drug properties. • Parenteral injection routes are often the routes of choice in acute care while oral route is the most common route used in chronic illnesses. • The physical and chemical properties of a drug can influence both the dosage form as well as the route(s) by which it may be administered. Key Concepts
- 31. References Physical Pharmacy:Physical Chemical Principles in the Pharmaceutical Sciences, 4th edn. (1993) Martin A.N. and Bustamanta, P. Lea and Febiger, Philadelphia. Physicochemical Principles of Pharmacy, 3rd edn. (1998) Florence, A.T. and Attwood, D., Macmillan, Basingstoke. Martindale, W. (1999) The Extra Pharmacopoeia, Royal Pharmaceutical Society of Great Britain, London. Modern Pharmaceutics, 3rd edn. (1999), Eds Banker, G.S., Rhodes, C.T., Marcel Dekker. Lachman, L., Liebermann, H.A. & Konig, J.L. 1986. The theory and practice of industrial pharmacy, 3rd ed., Chapter 5 to 21. Y.K. Chan et al. (eds.), Pharmacological Basis of Acute Care, Springer International Publishing Switzerland 2015 , DOI 10.1007/978-3-319-10386-0_2 OR http://www.springer.com/978-3-319-10385-3 www.wikipedia.com. Assessed on February 2019. For detail study refer reference books and journal mention in reference.
- 32.