Pharmacokinetics and Pharmacodynamics Quiz

Pharmacokinetics and Pharmacodynamics

• Drug movement through the body occurs in two phases: pharmacokinetic and pharmacodynamic.
• Pharmacokinetics describes the drug's movement, involving four processes: absorption, distribution, metabolism, and excretion.
• Absorption: Drug entry into the bloodstream.
• Distribution: Drug movement from bloodstream to body tissues.
• Metabolism: Body's chemical alteration of the drug for excretion. Primary site is the liver.
• Excretion: Drug removal from the body. Primary site is the kidneys, but also occurs via saliva, bile, lungs, sweat, and breast milk.
• Renal function tests often include creatinine and blood urea nitrogen (BUN).
• Potency: Amount of drug needed for a specific response.
• Maximal Efficacy: Dosage point where increasing the dose doesn't enhance the response.
• Therapeutic Index: Ratio of therapeutic dose to toxic dose.
• Therapeutic Range (Window): Safe dose range for therapeutic response without adverse effects.
• Onset: Time from administration to minimum effective concentration.
• Peak: Highest drug concentration in blood.
• Duration of Action: Time drug exerts a therapeutic effect.
• Agonists: Drugs activating receptors, producing a desired effect.
• Antagonists: Drugs preventing receptor activation, blocking a response.
• Side Effects: Secondary effects of drug therapy; all drugs have side effects.
• Adverse Drug Reactions: Unintentional, unexpected reactions to normal drug dosages.
• Drug Toxicity: Drug levels exceeding the therapeutic range; caused by overdose or accumulation.
• Tolerance: Decreased responsiveness to a drug over time.
• Placebo Effect: Drug response unrelated to the drug's chemical properties, influenced by patient expectations.
• Drug Interaction: Altered drug action due to interaction with other drugs.
• Food can affect drug pharmacokinetics (increase, decrease, or delay).
• Drug-Induced Photosensitivity: Skin reaction from drug-UV light interaction.

Complementary and Alternative Therapies

• 40% of adults use complementary/alternative medicine with traditional therapies.
• These therapies lack premarket safety and efficacy testing and standardized manufacturing.

Geriatric Considerations

• Older adults frequently use OTC drugs and supplements.
• Increased risk of adverse reactions and drug interactions, often leading to hospitalization.
• Age-related factors influence absorption, distribution, metabolism, and excretion.
• Absorption changes: Slowed gastric emptying, reduced blood flow, decreased acid production.
• Distribution changes: Decreased muscle mass, increased fat.
• Metabolism changes: Decreased hepatic blood flow.
• Excretion changes: Decreased renal function.
• Drug dosages adjusted for weight, lab results, and comorbidities.
• Drug toxicity possible at dosages within the therapeutic range for younger adults.
• Polypharmacy: Use of multiple drugs beyond clinical need.
• Older adults more likely to visit ED or be hospitalized due to adverse drug events.
• Common culprits are blood thinners, diabetes/seizure meds, cardiac drugs, and pain relievers.
• Nonadherence is a problem, especially in older adults, potentially due to insufficient understanding of the treatment regimen.

Drugs in Substance Use Disorder

• All drugs can be misused.

• Drug use is a complex social and health issue with severe consequences (family dysfunction, job loss, etc.).

• Substance Use Disorder: Recurrent use causing significant impairment (health problems, disability).

• Examples of Substance Use Disorders:

  • Alcohol: Associated with significant health issues (stomach, heart, cancer, brain damage, liver cirrhosis).
  • Cannabis: Associated with chronic cough, respiratory infections, cancer risk.
  • Opioids: Pain relief; powerful reward system stimulation; "downers". Naloxone for respiratory depression treatment; Naltrexone & Methadone to treat opioid use disorder (safe when prescribed with counseling).
  • Tobacco: Nicotine stimulates dopamine, etc., leading to stimulation, reward, and stress relief; severe, long-term damage. Nicotine replacement therapy, bupropion, and varenicline.
  • Cough/Cold Products: Dextromethorphan/promethazine-codeine can be psychoactive in high doses.
  • Anabolic-Androgenic Steroids: Muscle/bone growth and sexual characteristics; misuse leads to long-term health risks (kidney/liver damage, heart issues, cholesterol changes).

• Drug misuse increases dopamine and other neurotransmitter availability in the brain's reward circuit.

• Drugs interfere with neurotransmitter function leading to faulty transmission and excessive stimulation.

• Pain management is a priority, and narcotic analgesics use for pain doesn't worsen substance use disorder.

• Substance use disorder can cause nurses to enter treatment programs with compliance monitoring and abstinence requirements upon return to work.

• Excessive caffeine use is not considered a substance use disorder.