Lecture 53 - Pharmacology Flashcards
Drug
A substance used in prevention, diagnosis, treatment or cure of a disease
Pharmacology
Study of drugs
Pharmacotherapeutics
Deliberate therapeutic application of drugs which can be divided into pharmacodynamics and pharmacokinetics
Pharmacodynamics
What the drug does to the body
Pharmacokinetics
What the body does to the drug
In order for drugs to be effective drugs have to (4)
1) Enter the body and cross barriers to entry (pass through skin, gut or other membranes)
2) Be distributed by the blood to the site of action (determines concentration of drug at site of action)
3) Be biotransformed (enzymes increase/decrease drug action)
4) Be excreted (remove drug/metabolite from body)
Drugs have to cross barrier to enter, how they pass is through (2)
1) Active diffusion using a carrier mediated transport
2) Passive diffusion through a cell membrane/pore
What are 5 pharmaceutical strategies to improve absorption and distribution
- Multilayer tablets (enteric coated)
- Sustained release capsules (resin)
- Depot injections (oily, viscous, particle size)
- Skin patches (nicotine, nitroglycerin)
- Pro-drugs (morphine -> codeine)
Explain the metabolism of drugs by the body
Drug molecules are processed by enzymes intended to convert natural compounds which will change their actions (increase or decrease), mainly occurs in the liver
Excretion
Removal of drugs from the body through urine, bile, sweat saliva, expired air and breast milk (kidney is responsible for the bulk of excretion)
What happens when excretion is inhibited
Drugs and waste accumulate which results in toxic affects
What are the 3 excretion parameters
- Rate of elimination
- Half-life
- Steady-state concentration
Rate of elimination
Volume of drug cleared per unit of time
Half-life
Time required to reduce the plasma concentration to one half its initial value
Steady State Concentration
The concentration point at which amount of drug administered = the amount of drug being cleared
Explain the Concentration-Time relationship of drug efficacy
Blood concentration of the drug goes up and the drug starts to get broken up at its peak and then the slope as it goes down represents the decreased drug concentration as it is excreted. The drugs must reach minimum concentration threshold to have an effect and must not pass the maximum concentration threshold or else adverse effects occur.
Explain the steady state diagram
This is when multiple doses are given over time. At first dose doesnt reach minimum threshold concentration and needs more doses to give it that push to pass concentration. The drug will then be in a constant phase of being in between the minimum and maximum efficacy concentration of the drug which causes a steady-state. This is where want drugs to be at when they are administered. Why we ask patients to take medications at the same time each day.
What are 3 types of pain management
- Non-opioid analgesics
- Opioid analgesics
- Adjuvant medications
Describe the analgesic ladder
Acetaminophen dose, mechanism of action, onset of effect, duration and adverse effects
Non-prescription vs prescription names for NSAIDS
NSAID’s role, dose, response, onset, duration, and mechanism of action
NSAIDS adverse effects and ways to prevent these effects
How do NSADS cause hypertension (chronic use) and nephrotoxicity (high dosage)
What are 2 practical points for physiotherapists in regards to drug use (non-opioid analgesics)
- Non-opioid analgesics decrease mild-moderate musculoskeletal pain which increases participation in rehab
- NSAID’s decrease inflammation that could result from aerobic activities
What are 2 effects of NSAIDS/non-opioid analgesics that could interfere with rehab and their possible therapy solutions
Problems:
1. HEMORRHAGE INTO MUSCLES AND JOINTS AS A RESULT OF AEROBIC ACTIVITES THAT MAY PRESENT AS MUSCLE AND JOINT SORNESS
2. Nephropathy can lead to electrolyte imbalances and hypertension
Solutions:
1. Check BP prior to and during and after aerobic activities
2. Differentiate delayed onset muscle soreness from arthropathy/myopathy due to hemorrhage
Name some opioid products (9)
Opioid relative potency chart
What is special about morphine
That is where we move to step 2/3 on the pain ladder, so anything above morphine is milder (step 1)
Whats the difference between this list
IR = immediate release
Contin (ER/ES): Continuous release (long-acting)
Difference between short acting and long acting oral opioids
List 6 opioid combo products
What are some common and less common adverse effects of opioids
Tolerance
Higher dose required for chronic use (disease progression is a factor)
Physical dependence
Biologic phenomenon that occurs when you become dependent on a drug and this is why tapering of medications is important
Psychological dependence (addiction)
Pattern of drug use characterized by craving for drugs, but is rare when treating true pain disorders
Alpha Agonists
Neuropathic pain
Anesthetics
Loss of sensation (temporary)
Anticonvulsants
Neuropathic pain
Antidepressants
Neuropathic pain
Antihistamine
Nausea, pruritus
Benzodiazepines
Pain with anxiety
Bisphosphonates
Bone pain (cancer)
Corticosteroids
Bone pain (cancer)
Muscle relaxants
Spasticity
NSAIDs/COX-II Inhibitors
Anti-inflammatory
Opioid analgesics [increase/decrease] pain levels and allow increased participation in rehab
decrease
What are effects of opioids that interfere with rehab and their possible therapeutic solutions
Effects:
1. Sedation, mental slowing, and drowsiness can affect patient interventions
2. Respiratory depression can lead to hypoxia and hypercapnia and blunt exercise response
Solutions:
1. Target interventions at peak levels for maximum analgesic benefit
2. Monitor for shortness of breath, respiratory rate
