drug adminstration routes
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Drug Administration Routes
By:Seragaldin M. AbdulqaderClinical pharmacology for nursesUniversity of Raparin/school of nursingThe lecture for undergraduate students:
2015 -2016
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Definition A route of administration in pharmacology and toxicology is the path by which a drug, fluid, poison, or other substance is taken into the body.
Routes of administration are generally classified by the location at which the substance is applied. Common examples include oral and intravenous administration.
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Definition First Pass Effect:When a drug is administered orally, the drug is absorbed by the mesenteric veins. These veins drain into the portal vein which flows into the hepatic sinusoids.
Half-life: The amount of time required to eliminate 50% of the drug in the body. The half-life can be determined from a semilogy graph of the plasma concentration versus time or it can be calculated from the elimination constant.
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Definition
Pharmacokinetics, sometimes abbreviated as PK that is a branch of pharmacology dedicated to determining the fate of substances administered externally to a living organism via specific route to the drug characteristics.
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PharmacokineticA process which formed from:
Liberation- the process of release of a drug from the pharmaceutical formulation Absorption - the process of a substance entering the blood circulation.
Distribution - the dispersion or dissemination of substances throughout the fluids and tissues of the body.
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PharmacokineticMetabolization (or biotransformation, or
inactivation) – the recognition by the organism that a foreign substance is present and the irreversible transformation of parent compounds into daughter metabolites.
Excretion - the removal of the substances from the body. In rare cases, some drugs irreversibly accumulate in body tissue
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Routes of Administration/Enteral1. Oral route (p.o.):EasyUsually safeEconomical
Limitations/RisksRelatively slowLess predictableFirst pass effectPatient compliance
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Routes of Administration/Enteral2. Sublingual (SL):Rapid responseNo first pass effectBypasses GI acids and enzymes
Limitations/RisksNot used for irritating substancesMany molecules do not penetrate oral mucosa
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Routes of Administration/Enteral3. Rectal (PR):Unconscious patientsVomiting patientsSmall childrenMinimal first pass effectBypasses GI acids and enzymes
Limitations/RisksIrregular and incomplete absorptionNot used for irritating substancesSolutions must be isotonic
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Routes of Administration/Parenteral1. Intravenous (IV):Permits titration of dosageLowest intra-individual variabilityMost rapid response (emergencies)Most suitable for irritating substances and large volumes
Limitations/RisksGreatest risks: overdose, anaphylaxis, infection, embolism,
vascular injury, and phlebitis
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Routes of Administration/Parenteral3. Subcutaneous (s.c.):Slower absorption than i.m.Absorption slowed by vasoconstriction
Limitations/RisksNot used for irritating substancesLarge volumes are painful
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Routes of Administration/Parenteral4. Intraperitoneal (i.p.):Provides large absorbing surfacePrimarily used on lab animals
Limitations/RisksFirst pass effectRisks: adhesions, infection, injury
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Routes of Administration/Parenteral5. Topical: Useful for local effectsPoisons and toxins
Limitations/RisksLeast effective for systemic absorption
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Routes of Administration/Parenteral6. Pulmonary Very rapid absorptionUseful for gases, vapors, aerosols
Limitations/RisksNot used for irritating substancesDifficult to control dose
