Pharmacology Flashcards
What is pharmacology?
Studying the effects of drugs on the function of living systems
What is the definition of drug?
a chemical substance of known structure, which, when administered to a living organism, produces a biological effect.
What is a medicine?
chemical preparation administered with the intention of producing a therapeutic effect.
what is the difference between the drug and the medicine?
The medicine will contain the drug (active ingredient) and stabilisers, solvents, and other stuff that make the drug more effective.
What are the disciplines that feed in to pharmacology?
- chemistry (structure and target)
- physiology (normal biological function)
- pathology ( disease/ damage - process/ cause/ progression)
What is the book that is considered one of the oldest pharmacological books?
The Ebers Papyrus (Egyptian)
What did Pedanius Dioscorides do?
Wrote 5 volume encyclopedia (De Materia Medica) Which contain details about medicines used by Greeks, Romans, and other civilizations.
What is pharmacopoeia? and what is the first pharmacopoeia?
reference book containing details of drugs and their use. De Materia Medica
What are the characteristics defining the therapies before the birth of modern pharmacology?
- based on anecdotal evidence, spiritual beliefs and availability
- no understanding of how drugs work
-not patient friendly - flimsy science
- lacked control and credibility
Who are the fathers of pharmacology? and what did they do?
Rudolf Buccheim:
- first pharmacology professor
- emphasised the importance of defining drug mode of action
Oswald Schmiedeberg
- published outline of pharmacology
- defined modern pharmacology and pharmacologist
-separated between pharmacologists and clinicians.
What is the difference between a pharmacologist and a clinician?
Pharmacologist: concerned with investigating how drugs work.
Clinicians: concerned with the use of the drugs to treat
What did make pharmacology a precise, mechanism-based science?
Critical advancements in related disciplines ( chemistry and biomedical sciences)
What is pain?
broad class of unpleasant sensations ( Stinging, burning, pinching, aching)
Why do we feel pain?
- warning from actual or potential tissue damage
- encourage to withdraw limb from danger
- promote protection of damaged tissue to aid healing
- ensures we remember the incident and learn from the experience.
What are some of the early ways to relief pain?
- spells and incantations
- diet
- exercise
- consumption of potions/ formulations
- removal of painful limb/tissue/organ
- bleeding
- purging
- burning/ scalding
(aimed to restore the humoral balance)
What is opium?
gummy substance extracted from opium poppy plant
How did Hippocrates use opium?
used opium to treat headaches, coughs, asthma, melancholy
How was opium used before it was refined?
dissolved in alcohol (tincture of opium)
What were opium uses?
medicinal and recreational: induce analgesia, euphoria, sleep, suppress coughing and prevent diarrhoea
What was the first active ingredient isolated from opium? and who isolated it?
morphine, Friedrich Serturner
What are the components extracted from opium?
morphine, codeine
What is the significant that the extraction of morphine has in the history of pharmacology?
- first isolation of an active ingredient for any drug
- first proof that pure chemical in plants and natural products were responsible for biological responses.
What was morphine marketed as?
marketed by Serturner as
- analgesic
- treatment for alcohol and opium addiction
What was one of morphine’s first use?
medicine for children!!
Who invented the hypodermic needle?
Alexander Wood
How did the hypodermic needle changed the use of morphine?
- originally morphine was taken orally ( less potent/addictive)
- intravenous administration increased its potency
- increased opioid abuse
- addiction emerged as a side-effect.
How was morphine used as a battlefield analgesic?
- ampoule of morphine with attached needle for use in WWII bc:
- effective painkiller
- effects are almost instantaneous
What is diacetylmorphine?
- Heroin
- semi-synthetic opioid
- cough suppressant and analgesic
- ways of intake
*oral - converts to morphine
*intravenous - more potent/ addictive - one of the most addictive drugs in the world
What are the four main categories of drug targets?
- receptors
- enzymes
- carrier molecules
- ion channels
drug can either stimulate (agonist) or inhibit (antagonist) the target
How did Rene Decartes describe pain pathway in Treatise of man?
1) activation of a spot on the skin surface
2) Activation pulls a thread connected to a valve in the brain
3) Allows animal spirit stored in brain cavity to flow out which is responsible for:
*pain
*withdrawal of the limb from the pain source
*focusing toward the origin of the pain
What is the modern pain pathway?
- pain source (heat)
- pain receptors
- sensory nerve
- spinal cord nerve fibre
- nerve fibre ascends spinal cord to brain
- thalamus
who discovered the opioid receptors?
Solomon Snyder
What is an opioid receptor and where can it be found?
- present in the brain and spinal cord
- bind to opioids
- has several sub-types
- explains opioid actions
How do opioids work on opioid receptors?
inhibit the nerve fibre from firing by binding to it, hence pain relief.
How did the understanding of the pain pathway allow further development and discoveries in regard to drug design?
- developing synthetic drugs based on morphine with subtle differences that alter the activity and the properties of the new drug.
What are some examples of semi-synthetic opioid drugs?
- Oxymorphone: potent analgesia/ reduced euphoria
- Oxycodone and Buprenorphine: moderate analgesia/ reduced dependence
- Methadone: mild long-lasting analgesia/ dependence replacement
- Pethidine: mild-moderate analgesia/ rapid onset/ short-acting
- Fentanyl: very potent analgesia/ rapid onset/ short-acting
How does the pain pathway work normally to limit the sensation of pain? (without opioid intake)
- Mechanism 1: rubbing
1) rubbing
2) sensory receptors connected to a nerve fibre
3) spinal cord
4) inhibition of pain signal in the spinal cord
*less pain signals reach the brain - Mechanism 2: the descending pain-inhibitory pathway
1) nerve fibre originates in the brain
2) release endogenous opioids (enkephalins/endorphins) on the spinal cord
3) inhibition of pain pathway in the spinal cord
*discovered by Kosterlitz and Hughes in Aberdeen- Kosterlitz and Hughes purified and identified the structure of 2 enkephalins
How does the descending pain-inhibitory pathway get stimulated?
- stress (adrenaline)
- emotions
- opioid drugs
What are some of the other methods of analgesia (other than opioid drugs)?
- local anaesthetics + anti-inflammatory drugs
(ibuprofen, paracetamol, aspirin)- prevent pain receptors being activated
- TENS (transcutaneous electrical nerve stimulation)
- activates inhibitory sensory fibres (like rubbing)
- general anaesthetics
- induce loss of consciousness (no memory of pain)
- acupuncture
- stimulates release of enkephalins
What is cannabis?
an extract from Cannabis sativa plant
What are some of cannabis sativa preparations?
- Stalk:
fibre used to make hemp - Dried flowers/leaves:
used to make marijuana - Resin:
used to make hashish
What was cannabis originally used for?
used for hemp
Who mentioned the medicinal/ psychoactive effects of cannabis?
- Dioscordis in De Materia Medica
- Greek historians reporting on central Asian cultures
what are the main constituents of cannabis?
- tetrahydrocannabinol (THC): main active compound
- cannabidiol: THC precursor
- cannabinol: spontaneous product of THC breakdown
*collectively termed are cannabinoids
*lipid soluble
*active and psychoactive effects
What is the most potent cannabinoid?
tetrahydrocannabinol (THC)
What region of cannabis sativa is higher in THC concentration?
Resin
What are the physiological and psychoactive effects of THC on the central nervous system?
- loss of short-term memory
- increased confidence
- reduced co-ordination
- catalepsy
What are the physiological and psychoactive effects of THC on the digestive system?
- reduced nausea and vomiting
- stimulates appetite