Compiled from lectures notes, this is a condense but detailed summary of the whole module (and more) all accessible in one place, in a logical order, easy to search in and use for revision
BHCS1005 Summary Notes
Pharmacology – study of medicines/drugs, including their action, use and effects on the body
Formulation – how drugs are made so can be administered via various routes, depends on
• Barrier the drug is capable of passing
• Setting in which drug will be used
• Urgency of medical situation
• Stability of drug
• First pass effect – metabolism of drug by liver
Drugs are named with 3 names
• Chemical – based on molecular structure
• Non-propriety – simplified name based on chemical name (e.g. aspirin for salicylic acid)
• Propriety – given by manufacturer as a trademark
Suffixes to identify drug groups
• Beta-blockers; olol
• Benzodiazepines; azepam, azolam
• HMG-CoA reductase inhibitors; statin
• Serotonin receptor antagonists; setron
• ACE inhibitors; pril
• Monoclonal antibodies; mab
• Local anaesthetics; caine
• Azoles; azole
Drug administration
• Injection – intravenous, intramuscular, subcutaneous
• Oral – tablet
• Sublingual – mouth spray (used to target angina attacks)
• Suppository (rectal)
• Inhalation – asthma inhaler
• Topical – skin cream
• Transdermal – skin patch (reaches capillaries under skin, topical only reaches to dermis layer)
Half-life – time taken for plasma concentration of drug to decreases by 50% after discontinuance
Distribution half-life – rapid decline of [drug plasma] as dose distributed around the body
Elimination half-life – time taken for half of the [drug] to be excreted (depends on metabolism and
excretion)
Loading dose – initial high dose given to achieve therapeutic dose quickly
Maintenance dose follows to maintain [plasma]
Onset – time for drug to start working
Duration – length of time drug is therapeutic
Doses either given as a single dose (one off), continuous infusion or intermittent dose
Pharmacokinetics relates to the absorption and distribution of the drugs in the body
Drugs absorbed via mechanisms of membrane transport
• Passive diffusion – rapid for lipophilic, non-ionic and small molecules
• Facilitated diffusion
• Aqueous channels
• Active transport
1
,BHCS1005 Summary Notes
Drug distribution depends on
• Permeability of membrane to drug
• If drug is protein-bound or not
• Depot storage – lipophilic drugs accumulation in fat stores, Ca2+- binding drugs accumulate in bone
• Apparent volume of distribution (Va) – volume required to contain administered dose if that dose
was evenly distributed at the concentration measured in plasma (measure of [drug] in plasma vs
drug in body)
Drug metabolism
• Change active to inactive/less active drug
• Change prodrug to active drug
• Phase 1
o Uses oxidase enzyme family cytochrome p450 to unmask/introduce polar groups
o Other non-p450 reactions – alcohol dehydrogenase
• Phase 2
o Reaction which conjugates drug/phase 1 metabolite with hydrophilic, endogenous species
o E.g. of endogenous compounds
▪ Gluconic acid ▪ Methyl group
▪ Sulfate group ▪ Acetyl group
▪ Amino acid ▪ Glutathione
Drug excretion is affected by glomerular filtration and tubular secretion/reabsorption
Drug clearance – pharmacokinetic variable of elimination
CLp = rate of elimination / [plasma drug]
CLp – constant for substances eliminated by 1st order kinetics (ml/min), represents volume of plasma
completely cleared of chemical per unit time
Drug receptors are (glycol)proteins present of cell surface, organelles or in cytoplasm – there are finite
number of receptors on a given cell therefore receptor-mediated responses plateau upon/before receptor
saturation
Events after drug binding
• Ion channel opens
• 2nd messengers activated, initiating a series of reactions in cell which transduce signal stimulated by
drug – normal cellular function inhibited or stimulated
Affinity – strength of binding between drug and receptor
Dissociation constant (Kd) – measure of drug’s affinity for a given receptor
Agonist – drugs that bind to plasma membrane or intracellular receptors to stimulate cellular function
Partial agonist – drug fails to produce maximal effects even when all receptor bound with drug
Antagonist – blocks action of agonist
Competitive antagonist – competes with agonist for receptor
Non-competitive antagonist – binds to allosteric site to induce conformational change of receptor so
agonist no longer fits
Irreversible antagonist – binds permanently to receptor
Pharmacology at organism level
• Efficacy – degree to which drug is able to induce maximal effects
2
,BHCS1005 Summary Notes
• Potency – amount of drug required to produce 50% of maximal response that the drug is capable of
inducing
• Graded dose-response curve – graphs showing magnitude of drug actions against conc or dose
required to induce these actions
Pharmacology at population level
• EC50 – [drug] which induces a specified clinal effect in 50% of subjects
• LD50 – [drug] that induces death in 50% of subjects
• Therapeutic index – measure of safety of the drug = LD50/EC50
• Margin of safety – margin between therapeutic and lethal dose of drug
Drug interaction
• Altered absorption – change rate/extent of absorption
• Altered metabolism – increase/decrease metabolism by stimulating/inhibiting CYP isoenzyme
activity
• Altered excretion – changes to renal excretion (ADH, ACE inhibitors, NSAIDs)
• Plasma protein competition – competition of binding to proteins
• Effects of these interactions
o Addition – response of combined drugs = combined responses of individual drugs
o Synergism – response of combined drugs > combined response
o Potentiation – drug with no effect enhances effect of 2nd drug
o Antagonism – drug inhibits effect of another drug
Tolerance – decreased response to drug (more required for same effect)
Dependence – patient needs drug to function normally
Withdrawal – occurs when drug is no longer given to dependant patient
Pathology - structural, biochemical and functional changes in cells, tissues and organs that underlie disease
• To understand the specific molecular, cellular and tissue responses to injury by understanding how
tissues and cells can be injured
• Changes at these levels important to diagnosis and evaluation
Health – a state of complete physical, mental and social wellbeing, not merely the absence of
disease/infirmity
Disease – condition of the living animal/plant body or its parts that impair normal functioning, manifested
via signs and symptoms
Homeostasis – disordered homeostasis has significant effect of health; extent of significance dependant on
which body parameter affected and the importance of that parameter
Study of human disease (first 4 encompass pathology)
• Aetiology – cause
• Pathogenesis – mechanisms/process
• Pathological/clinal manifestations
• Complications and sequelae
• Prognosis
• Epidemiology
• Prevention
Cell death
• Necrosis – uncontrollable breakdown due to injury, organ softens and discolours
o Coagulative – protein denaturation more than enzymatic breakdown (e.g. cardiac
infarction)
o Liquefactive – enzymatic breakdown more than protein denaturation, loss of cellular
architecture (e.g. brain infarct)
o Caseous – pulmonary TB
• Apoptosis
o Controlled/programmed cell death due to DNA damage or growth
o Carried out in ordered process of orchestrated biochemical processes
o Advantage of cell cycle
o Seen when tissues are sculpted (fingers and toes)
o Initiation (caspases become active) and execution (caspases cleave DNA damage causing cell
death)
o No inflammation (unlike necrosis) but macrophages do engulf cell fragments
Hypertrophy - increase in cell number
• Proliferation of cells in tissue/organ
• Physiological – breast growth in pregnancy
• Pathological – growth of adrenal gland due to excess [ACTH]
Atrophy – decrease in cell size
• Decrease in cell size means cell was normal size
• Phys – decrease in uterus after pregnancy
• Path – loss of blood supply to organ/tissue, ageing or bed rest
Hypoplasia – incomplete development of organ/tissue (many potential causes during embryonic/foetal
growth)
Dysplasia – abnormal type of cell within a tissue
• Abnormality in the maturation of cells within a tissue
• Seen as an increase in number of immature cells compared to mature cells
• Abnormal cells confined in original tissue
• Contrasted with carcinoma in situ where no mature cells are formed
• Early stage of neoplastic growth in cancers?
Metaplasia – normal epithelium in abnormal location
• Mature, differentiated cells replaced with another type of mature, differentiated cell
• Barrett’s oesophagus – squamous epithelium replaced with columnar epithelium from stomach
• Transitional epithelium - squamous epithelium in urinary bladder due to bladder stones
Disease classification
• Topography – body region involved (CVD)
• Anatomic – Organ/tissue involved (heart disease)
4
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller AH1984. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $11.77. You're not tied to anything after your purchase.
