CHAPTER TWO
Chemical Name:
• Describes the drugs chemical composition and molecular structure
Generic Name:
• Nonproprietary name
• Name given by the United Sates Adopted Names Council
Trade Name:
• Propriet
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CHAPTER TWO
Chemical Name:
• Describes the drugs chemical composition and molecular structure
Generic Name:
• Nonproprietary name
• Name given by the United Sates Adopted Names Council
Trade Name:
• Proprietary name
• The drug has a registered trademark
• Use of the name is restricted by the drug’s patent owner
Pharmaceutics:
• The study of how various drug forms influence the way in which the drug affects the body
Enteric-Coated Tablets:
• Coating prevents the medication from being broken down by stomach acids too fast
• Coating protects the stomach from the irritation of certain medications
• Do not crush or chew
Pharacokinetics:
• The study of what the body does to the drug
• Absorption, distribution, metabolism, excretion
Absorption:
• Movement of a drug from it’s site of administration into the bloodstream for distribution to the tissues
o Bioavailability: extent of drug absorption
o First-pass effect: amount of medication metabolized by the liver and not absorbed into bloodstream
• Routes:
o Enteral (GI tract)
▪ Orally, sublingual, buccal
▪ First pass effect, variable absorption
o Parenteral
▪ Intravenous
• Rapid onset; avoids first pass effect
• Nursing considerations: monitor drug, compabilities, IV site
▪ Intramuscular
▪ Subcutaneous
o Topical
▪ Avoid first pass effect; except rectal administration
▪ Transdermal
• Deliver constant amount
• Slower onset; prolonged duration
▪ Topical
• Delivers meds directly to affected area
• Decease systemic absorption
▪ Inhaled
Distribution:
• The transport of a drug by the bloodstream tot its site of action
• Water soluble vs fat soluble
o Blood-brain barrier
• Areas of rapid distribution
o Heart
o Liver
o Kidneys
o Brain
• Areas of slower distribution
o Muscle
o Skin
o Fat
• Protein-binding
o “bound drug” vs “free drug”
o Pharmacologically active vs inactive
o More free (unbound and active) drug = risk of drug toxicity
Metabolism/Biotransformation:
• The biochemical alteration of a drug into an inactive metabolite, a more soluble compound, a more potent active metabolite, or a less active metabolite
• Liver (main organ)
• Factors that decrease metabolism
o Cardiovascular dysfunction
o Rena insufficiency
o Starvation
o Obstructive jaundice
o Slow acetylator
o Ketoconazole therapy
• Factors that increase metabolism
o Fast acetylator
o Barbiturate therapy
o Rifampin therapy
o Phenytoin therapy
Excretion:
• The elimination of drugs from the body
• Kidneys (main organ)
• Other organs
o Liver
o Bowel
• Half life
o The time it takes for one half of the original amount of a drug to be removed from the body
o A measure of the rate at which a drug is removed from the body
o Most drugs considered to be effectively removed after about 5 half lives
o Steady state
▪ Physiological state in which the amount of medication excreted by the kidneys is equal to the amount of medication absorbed with each dose
Drug Actions:
• The cellular processes involved in the drug and cell interaction
Drug Effect:
• Physiologic reaction of the body to the drug
Onset:
• The time it takes for the drug to elicit a therapeutic response
Peak:
• The time it takes for a drug to reach its maximum therapeutic response
Duration:
• The time a drug concentration is sufficient to elicit a therapeutic response
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