Pharmacokinetics
the effects of the body on the drug
Pharmacodynamics
the effects of the drug on the body
Bioavailability
the percentage of the medication that reaches the systemic circulation
Absorption options for medications (7)
1. oral 2. sublingual - nitroglycerin3. inhalation - bronchodilators for asthma4. intramuscular - rapidly absorbed5. subcutaneous 6. intravenous - instantaneous absorption rate7. transdermal or topical - patch
Distribution
after absorption, get the drug to the site of action and later to liver/kidney for inactivation and excretion
Factors that affect distribution
-local blood flow-plasma protein binding-blood brain barrier-quantities of fat and muscle
Metabolism
eliminate drugs to maintain proper levels of medications
First-pass metabolism
drugs pass through the liver prior to entering systemic circulation. may decrease bioavailability.
Elimination
clearance is the volume of blood that is completely cleared of a drug per unit of time. This predicts the rate of elimination.
Renal excretion
the main site of elimination
Half-life
the amount of time it takes for the plasma concentration to drop to 50%
Agonists
endogenous substances like neurotransmitters, or hormones. must have an affinity to bind with receptors
Potency
compares two drugs as to their abilities to produce the same response and is not the same as efficacy.
Antagonists
substances or drugs that fit into and bind with receptor sites to block the receptor and not allow it to be activated. have affinity at the site, but no efficacy
Anti-Inflammatory Medications (aspirin)
Aspirin inhibits the enzyme cyclooxygenase (COX) and thus inhibits prostaglandin synthesis. Prostaglandins are mediators of the inflammatory process.
Anti-inflammatory medications indications
antipyretic, analgesic, anti-inflammatory, antiplatelet
Anti-inflammatory medications side effects
GI upset
Anti-inflammatory medications adverse effectrs
prolonged bleeding, GI ulceration, allergic reactions
Anti-inflammatory medications drug interactions
-warfarin (coumadin)-may displace phenytoin-may decrease renal excretion of methotrexate-alcohol and increase risk of bleeding