Pharmacokinetics & Pharmacodynamics: Drug Absorption, Metabolism, and Effects with complete verified solutions 2025-2026

Pharmacokinetics

4 essential processes of how drugs are absorbed, distributed, metabolized & excreted by the body.

Absorption

Routes of administration such as Mouth, IM, sublingual, subcut, inhalation, rectal, IV, topical, etc.

Bioavailability

% of drug that actually reaches the body's system; Highest is IV @ 100%.

Metabolism

Modification of drugs in the body, usually occurs in the liver and digestive system.

Pharmacodynamics

Study of specific drug effects on the molecules, cells, tissues, organs, and systems of the body.

Duration of Action

Length of time drug is active in body.

Short duration

Require multiple daily doses (3-4).

Long duration

Require 1-2 doses/day.

Sustained release

Tablet or capsule that dissolves slowly; has long lasting effects.

Adverse Drug Reaction

Any unintended effect of the medication including an exaggerated medication response.

Drug Tolerance

Reaction to a drug diminishes over time.

Drug Dependency

Physical dependency: Body adapts to the substance, then it needs the drug to function normally.

Withdrawal symptoms

Normal reaction where withdrawal symptoms are typically the opposite of what you took the medication for.

Psychological dependency

The mind craves the substance.

Extreme hypotension

Following BP meds as an example of an adverse drug reaction.

Orthostatic hypotension

A potential side effect of medications.

Blurred vision

A potential side effect of medications.

Decrease cognitive status

A potential side effect of medications.

Chewing long duration pills

Makes them release faster.

E-stim

Can affect the rate of drug absorption.

Analgesics

Opioids that can lead to psychological dependency.

Sleep aids

Benzodiazepines that can lead to psychological dependency.

Addiction

Strong cravings and overwhelming daily life. Continue to use despite negative impact on quality of life.

Principles of Safe Medication Use

Pain meds can affect the stages of healing. If the meds block your receptors, then what tells that part of the body to start the inflammatory response? Nothing.

Meds for Ortho Infections

Antibiotics can result in slowed recovery, joint damage, amputation, nonunions, hardware removal, death due to sepsis.

Antibiotic Compliance

Must take meds as prescribed for full course of therapy. Do not stop when you feel better. Around-the-clock dosing is important.

Meds for Pain & Inflammation

Reduces suffering & speeds healing. Pain is often undertreated because we're worried about addiction.

Types of Analgesics

Three types of analgesics: Opioids, Acetaminophen, Anti-inflammatory agents.

Nociceptive pain

Tissue damage, such as strain or sprain.

Inflammatory pain

Pain associated with conditions like arthritis or bursitis.

Neuropathic pain

Pain resulting from damage to nerves.

Acute pain

Pain that follows injury and disappears when the injury heals.

Chronic pain

Pain that continues longer than normal.

Opioid Analgesics

Related to opium, including morphine, oxycodone, and hydrocodone. Blocks transmission of pain to CNS.

Side effects of Opioids

Nausea & vomiting, sedation, drowsiness, hypotension, impaired judgment, physical dependence, and addiction.

Acetaminophen

Most commonly used OTC fever reducer and analgesic. Does not do well with inflammation.

Side effects of Acetaminophen

Hepatotoxicity (liver toxicity).

NSAIDs

Non-steroidal anti-inflammatory drugs, including aspirin, ibuprofen, naproxen, and ketoprofen. Commonly used OTCs for fever and pain.

Effects of NSAIDs

Effective for inflammatory pain; can affect GI tract and kidneys; don't mix with blood thinners.

Cox-2 Inhibitors

Still NSAIDs but prescription only, designed for people on blood thinners. Puts more stress on your cardiovascular system.

Celebrex

Type of Cox-2 inhibitor, only one approved in America right now, related to cardiac deaths.

Corticosteroids

Also called glucocorticoids, they have powerful anti-inflammatory effects.

Side effects of Corticosteroids

Increase risk for osteoporosis, increase blood glucose, muscle myopathy, edema, cataracts, etc.

Steroid Injections

Can soften your cartilage.