Pharmacology Flashcards
What is pharmacokinetics of medication?
It is the process of drug movement throughout the body necessary to achieve an action.
What are the four phases of movement of medication in the body?
Absorption
Distribution
Metabolism
Excretion.
What is pharmacodynamics of medication?
This is the study of the effects of the drugs on the body.
True or false. Medication can cause a primary or secondary physiologic effect or both on the body.
True.
The primary effect is the desired therapeutic effect.
The secondary effect are all other effects which may beneficial or harmful.
What is the trade name of the medication?
The name given to the drug by the companies which manufacture the drug. Individual drugs can have several different trade names, e.g Panadol
What is the generic name of medication?
The chemical name of the medicine, it is the same name no matter how the companies manufacture it, e.g. Paracetamol.
Define disintegrate of a drug in it’s solid form.
Tablet or capsule must disintegrate into small particles and combine with a liquid to form a solution. This is also known as dissolution.
True or false. The rate of dissolution is the time it takes for the drug to disintegrate and dissolve to become available for the body to absorb it.
True.
Also drugs that are disintegrated and absorbed faster in acidic fluids with the pH of 1 or 2 rather than a pH greater than 7.
Blood flow, pain might affect drug absorption. What are four others?
Stress
Hunger
pH
Foods that are solid, hot, or higher in fat content.
Poor circulation.
Exercise.
Explain absorption of medication.
Occurs across the mucosal lining of the small intestine, involving 2 processes - diffusion and facilitated diffusion.
What is facilitated diffusion?
The drug relies on a carrier protein to move it from an area of higher concentration to an area of lower concentration.
True or false. Lipid soluble drugs can easily pass through the mucous membrane?
True. This is because the mucous membrane lines the GI tract is composed of lipids and protein - therefore it easily moves.
Why is water soluble drugs harder to pass through the mucous membrane?
Water soluble drugs need a carrier, either an enzyme or protein to pass through the mucous membrane.
What are some examples of fat soluble drugs?
Some steroids, benzodiazepines and the statins.
What are some examples of water soluble drugs?
Antibiotics - penicillin, antihypertensive drugs (beta blockers) and certain antiviral drugs.
When injecting medication into the muscle, what area is best choice and why?
In the deltoid as it has faster blood flow and therefore absorbed faster.
Is absorption faster for medication given subcutaneous or via intramuscularly?
Via IM as it has faster blood flow.
What are two reasons would we not want to administer drugs via rectum?
Absorbed slower than orally.
The composition of the suppository base affects the drug absorption.
What is first pass effect for medication?
In the liver some drugs will be metabolised to an inactive form and then excreted. This will reduce the amount of active drug available to exert a pharmacological effect.
Does medication that is absorbed from the oral cavity subject to first pass metabolism?
No. It will enter the systemic circulation directly without entering the portal system, bypassing the liver. This could be medication give sublingual or buccal routes.
Is the stomach or small intestine the major site for absorption of medication?
The small intestine is.
The stomach has tight intracellular junctions and small surface area.
What effect does an empty stomach have on drug absorption?
With sufficient water, it will ensure dissolution and rapid passage into the small intestine. This is why many medication is given on an empty stomach.
Why is drug absorption predominately done in the small intestine?
It is highly vascularised.
Significantly larger area for absorption.
the pH of intestinal fluid is close to neutral.
Rectal drug administration maybe used for unconscious patients. What are two other reasons why?
- fasting patients.
2 Patient who can not swallow or severe vomiting.
Define bioavailability of medication.
It is the proportion of the administered dose that reaches the systemic circulation intake. Usually expressed as a % and the symbol F.
Administration of medication with food and other drugs will affect bioavailability of medication? What are 4 more?
Drug form
changes in liver metabolism
route of administration
Gastric mucosa and motility.
Define pain threshold.
Reflects the level of stimulus needed to create a painful sensation, and individual genetic makeup contributes to variations to pain threshold from one person to another.
Define pain tolerance?
Is the amount of pain a person can endure without having it interfere with normal functioning.
True or false.
Pain is as determined by the RN making the assessment?
False. It is what ever the patient informs you that they are experiencing.
What is nociceptive pain?
Inflammation of and damage to tissues activating specialized pain receptors. Sometimes this is in response to physiological or inflammatory pain. This type of pain is usually localized.
What is some differences between acute and chronic pain?
Acute - usually lasts less than 3 months, can be specific and treatable and usually subsides as healing and responsive to treatment.
Chronic is persistent, for more than 3months and can sometimes be difficult to determine the cause and difficult to treat.
Where do we find nociceptors?
a. skin
b. muscles
c. joints
d. visceral organs
e. all of the above
All of the above - these are activated when they detect extreme heat or cold and certain harmful chemicals.
Explain the pain gate theory?
Tissue injury activates nociceptors and causes the release of chemical mediators.
These substances initiate an action potential along the sensory nerve fibre and sensitize pain receptors.
Nociceptive action potential are transmitted via different afferent nerve fibres.
Are A pain fibres myelinated or unmyelinated?
They are myelinated and therefore fast or rapidly conducting -12-30m/s.
Are C fibres myelinated or unmyelinated?
Unmyelinated and therefore slow conducting.
How many neurons are involved in the spinothalamic pathway - bringing an impulse to the cerbral cortex.
Three - First order neuron - transmits pain impulses.
Second order neuron - carry the pain stimuli to the thalamus.
Third order neuron - reaches the cerebral cortex.
What are the four process of the physiology of pain?
Transduction
Transmission / conduction
Perception
Modulation
What is the main neurotransmitter responsilble for transmission of pain signals in the spinal cord?
Glutamate - these bind to the receptors causing it to open to cations (sodium and calcium). These enter the postsynaptic membrane resulting in deploraisation.
For opioid drugs, what are the key targets?
Synapses are the key targets for opioid drugs.
What are the 5 symptoms of inflammation?
redness
heat
swelling
pain
altered function
During the inflammation process, why might we see swelling, heat, redness and pain?
We will see redness as there is an increase in blood flow to the area.
Vasodilation occurs which is why we see redness.
An increase in vascular permeability causes plasma to leak from small blood vessels into the area of damage which we will see as swelling.
This leaking plasma brings clotting factors to the injured area.
How does pain occur in the inflammation process?
An increase in vascular permeability occurs, which is swelling. This swelling will stimulate the nociceptive neurons, which will sends a message to the brain.
What is the main prostaglandin involved in the inflammatory process with pain?
Prostaglandin E2 - it plays a role in transmitting pain signals in the spinal cord and hypothalamus.
What is the target for non-steroidal anti-inflammatory drugs (NSAIDS) in the pain pathway?
NSAIDS will synthesis the prostaglandin.
What is the key enzyme in the synthesis of prostaglandin?
Cyclo-oxygenase or COX and there are two, COX1 and COX2.
What is the difference between COX1 and COX2?
COX1 is involved in:
maintaining the integrity of gastric mucosa.
Inhibition of gastric acid secretion.
Smooth muscle contraction.
COX2 is the key enzyme in the inflamed area.
What role does Mast cells play in the inflammation process?
Release histamine, prostaglandins and neutrophil-attracting mediators.
Antihistamines - block the action of histamine.
Corticosteroids - reduce the release of mediators from mast cells.
Mast cell stablizers - help prevent the release of mediators from mast cells.
Where is paracetamol metabolised and what is the antidote in case of toxicity?
Metabolized in the liver - the risk of liver damage (hepatotoxic) and the antidote is N-acetylcysteine.
Opioids mimic the body’s own analgesic system. What do they bind to and inhibit the transmission of?
They bind to opioid receptors and inhibit the transmission of nerve impulses across the synapse.
What are the three main opioid receptors and their role in pharmacological action?
Mu receptors - analgesia, sedation, respiratory depression.
Kappa receptors - hypothermia, miosis
Delta receptors - dysphoria.
All have opioid effects.
Do opioids act on the CNS or PNS?
CNS - primarily activating the u-receptors.
What is the difference between local and general anaesthetics?
Local anaesthetics block calcium channels on nociceptive neurons which inhibit the transmission of pain signals to the brain.
Where general anaesthesia have actions on the CNS that induces analgesia, hypnosis and amnesia.
What is the antidote for a patient who has opioid overdose or toxicity?
Naloxone.
For a patient taking paracetamol, what should the nurse do?
a. teach the patient that caffeine decreases the effects of acetaminophen.
b. teach the female patient that oral contraceptives can increase the effect of acetaminophen.
c. encourage the patient to check package labels of OTC drugs to avoid overdosing.
d. report side effects immediately, as toxicity can cause severe hepatic damage.
e. monitor routine liver enzyme tests.
Encourage patient to check package labels of OTC to avoid overdosing.
Report side effects immediately.
Monitor routine liver enzyme tests.