Drug effects on other systems L19-25 Flashcards
local hormone
chemical messenger formed by tissue on which it acts
where is histamine formed
histaminocytes
histaminergic neurones
mast cells basophils
histamine formation
histidine break down by histidine decarboxylase to histamine
histamine breakdown
histamine oxidase breakdown if not stored
acute inflam response of mast cell
C3a/C5a receptors (complement component)
pathogen pattern receptors (pathogen)
hypersensitivity response of mast cell
immunoglobulin (Ig)E cell fixed antibody
arousal pathway
histamine neurones in TMN
spontaneously active
release histamine in wakefulness
emetic centre
histaminergic neurones in TMN receive vestibular input for sensory
mismatch of inputs to medulla
emetic (vomiting) centre activated in medulla
histamine receptor types
G-protein coupled
H1
H2
H3/4
H1
phospolipase C activated
triggers Ca2+
H2
adenlyl cyclase activated
triggers cAMP
H3/4
triggers cAMP
H1 functions
myosin phosphorylation
neuronal activation
nasal/bronchial secretions
vascular permeability
NFkB activation
sensory nerve endings
prociflam cytokine secretion
H2 functions
chronotropic heart rate increase
H1 and H2 functions
capillary permeability and dilation
inotropic increase of heart rate
rhinitis
inflammation within nose
sensory nerve ending stimulation
increases nasal secretions
capillary permeability and dilation
urticaria
sensory nerve ending stimulation
capillary dilation
anaphylaxis
rapid onset
HR rapid
consciousness loss
breathing difficulties
1st generation antihistamines
H1 receptor antagonists
prophylaxis
1st generation antihistamine pros
cheap/ effective
cross BBB ^ sedation and stops motion sickness
extra wanted effects due to broad selectivity
1st generation antihistamine cons
unwanted sedation/ adverse effects
can excacerbate other drugs anticholinergic adverse effects
muscarinic antagonist effects reversing parasympathetic activation
pupil dilation (blurred vision)
^ cardiac output
decreased exocrine gland secretion
decreased bladder contraction
a1-adrenoreceptor antagonist reversing sympathetic activation
vasodilation > hypertension/ dizziness
pros of 2nd generation antihistamines
add carbonyl groups (more polar)
less unwanted sedation
less anticholinergic effects
2nd generation antihistamines cons
don’t cross BBB as easily
gastric acid secretion pathway
stomach> gastric gland> parietal cell> proton pumps/ chloride co-transporter
peptic ulcer
perforation in lining of small intestine/ stomach
gram neg helicobacter pylori infection
peptic ulcer treatment
antimicrobials rid H.pylori
H2 antagonists competitively/ reversibly block histamine-binding
H2 antagonists cons
reoccurrence if H.pylori present and not erradicated
less effective for NSAID-induced ulcers
45 min action onset
affects other drug metabolism
decreases drug efficacy requiring acidic environment
H2 antagonists pros
all 4 effective for H.Pylori ulcers
heartburn effective
cheap
safe
Proton Pump Inhibitors
decrease H+ secretion
prodrug
acid resistant coating (removed in duodenum)
absorbed/ transported to parietal cell
metabolised to active and bind to PP
decrease gastric acid secretion
PPI pros
v effective
long duration
PPI cons
delayed action onset
increased risk of gut infection
gut pH above physio level
inflammation
local accumulation of fluid containing plasma proteins and white blood cells
non-specific/ dynamic/ 2nd line of defence against infection
inflammation functions
restricts damage/ infection
removes causative agent/ damaged tissue
allows immune cell access to site for repair
cardinal signs of acute inflammation
calor
dolor
oedema
erythema
innate responses inducing acute inflammation
bacteria-triggered cytokine/ chemokine release from macrophages
vasodilation/ ^vascular permeability
inflam cell migration > inflam mediators
cells recruited acute inflammation
macrophages
dendritic cells
eosinophils
neutrophils
basophils
mast cells
4 inflammation stages
- tissue damage (sentinel cell activation)
- vasodilation and vascular permeability
- cell recruitment
- tissue repair (clotting/ annexin and fibrin release)
eicosanoids
physio active lipid compounds
signalling molecules via enzymatic/non-enzymatic oxidation of arachidonic acid
prostanoids (prostaglandins, thromboxane)
leukotrienes
prostaglandins
PGI2 > Prostacyclin (vasodilation/ stops platelet activation)
PGE2 > Prostaglandin (fever/pain and vascular permeability)
TXA2 > thromboxane (platelet activation and vasoconstriction)
types of anti-inflammatory drugs
NSAID’s
glucocorticoids (steroidal anti-inflam)
immuno-suppressants
anti-histamines (antagonists of histamine receptors)
non-opioid analgesics
paracetamol
aspirin (NSAID)
ibuprofen (NSAID)
celecoxib (NSAID)
paracetamol pros / cons
:) analgesic/ antipyretic activity
:( no anti-inflam action/ liver damage on overdose
aspirin pros/cons
:) acetylates COX
irreversible inhibitor
anti-platelet activity
:( ^risk of GI bleeding/ irritation
ibuprofen pros/ cons
:) short-term analgesic
anti-inflam
:(gastric irritation/ ^ulceration risk
celecoxib pros/cons
:) COX-2 inhibitor decreases side effects
:( ^risk of stroke/ heart attack following FDA cat.d use
arachidonic acid on COX-1
housekeeper
many roles
arachidonic acid on COX-2
Inflam cell activation
anti-inflam/ analgesic/ antipyretic
side effects of non-opoid analgesics
immunosuppression
hyperglycaemia
growth impairment
natural corticosteroid synthesis suppression
gene targets of non-opioid analgesics
^tyrosine aminotransferase (immunosuppressive)
^lipocortin (eicosanoid generation inhibition)
decrease NFkB regulated genes (COX)
decrease activator protein 1 regulated genes (wound-healing/ collagenase/ vit C/D metabolism)
ACTH effects
adrenocorticotrophic hormone
^glucocorticoid hormones
^ cortisol proportion
^ w stress
manufactured glucocorticoids
beclometasone (asthma inhaler)
hydrocortisone cream
prednisolone (allergies/ skin infection)
glucocorticoid/ cortisol
prevents inflam mediator release
decreases TNF-a
twitches toward Th2 immune response via IgE
Cushing’s syndrome
cortisol build up
latrogenic> long-term high dose cortisol use
endogenous> ACTH over-production in body
easy bruising/ purple striae/ muscle wastage/ atherosclerosis/ moon phase
common bacterial targets for antibiotics
cell membrane
cell wall (e.g. penicillins)
protein synthesis (e.g. macrolides/ tetracycline)
RNA polymerase
DNA synthesis (e.g. fluroquinolones)
folate metabolism (e.g. sulphonamides)
lactam
cyclic amide
beta-lactam
lactam w heteroatomic ring structure (3C and 1N)
types of penicillin
benzylpenicillin
broad spectrum
beta-lactamase resistant
extended spectrum
reversed spectrum (more g-)
benzylpenicillin
original form
less active against gram negatives
acid labile
oral (Less absorbed)
parenteral (slow IV/ IM/ high availability)
broad spectrum penicillin
amino group >penetration of outer membrane of g-
better absorption profile
beta lactam antibiotic mechanism
inhibit enzyme (transpeptidases) > no links in peptidoglycan cell wall
swell and rupture of cell wall
multiplying organisms
peptidoglycan monomer
N-acetylmuramic acid with N-acetylglucosamine and tetrapeptide connecting
penicillin pharmacokinetics
A > varies
D> wide dist no CSF entrance
M> short half-lives (30-80mins)
E> kidney w 90% tubular secretion/ clearance reduction in neonates
probenecid
inhibits tubular secretion
penicillin adverse reactions
hypersensitivity
GIT disturbance
haemostatic effects
folate biosynthesis
pABA>(dihydropteroate)>folate>(dihydrofolate reductase)>tetrahydrofolate>thymidylate synthesis> DNA
Sulphonamide mechanism
blocks dihydropteroate synthetase
bacteriostatic
sulphonamide pharmacokinetics
A> oral/ absorbed from stomach and intestines
D> wide inc. CNS
M>n-acetylation metabolism in liver
E>urine ~30mins
sulphonamide adverse reactions
photosensitivity
stevens-johnson syndrome
hemopoietic disturbances
fluoroquinolones
broad spectrum
gram+/g-
target DNA replication via TII topoisomerases
absorbed in upper GI tract/ excreted in tubular
CYP182 inhibition
quinolone inhibition
DNA gyrase > supercoiling regulation and packaging (inhibited in gram negatives)
DNA topoisomerase IV > gyrase homologue (inhibited in g+)
euk vs pro ribosomes
euk> 80S
pro> 70S
50S (23S/5S) and 30S sub-units
macrolide mechanism of action
block peptide translocation
bind near RNA exit tunnel
peptidyl transferase RNA drop off
macrolide ADME
A > capsules protect from gastric juices
D> crosses placenta not BBB
M>demethylation
E> excreted in bile
macrolides adverse reactions
cholestatic hepatitis
GIT
transitory auditory impairments
tetracycline mechanism of action
interrupts elongation phase of synthesis
sterically inhibits tRNA binding
unbinds/ rebinds/ futile loop
tetracycline ADME
A> fasting state
M> long half-lives due to enterohepatic recirculation
E> bile / glomerular filtration
hallmarks of cancer
resisting cell death
sustaining proliferative signalling
evading growth supressors
activating invasion/ metastasis
inducing angiogenesis
enabling replicative immortality
cancer treatment options
surgery
biological
radiation
chemotherapy
drugs affecting G1 phase
protein depleting
asparagine + asparaginase
aspartic acid/ ammonia
tamoxifen
S requires activation of hormone regulated genes and so replaces oestrogen in cancer cell to stop growth and proliferation
Alkylating agents
ciplatin
nitrogen mustard
cyclophosphamide
daunorubicin
antimetabolites
methotrexate
5-fluoruracil
6-mercaptopurine-A
topoisomerase inhibitors
T1-irinotecan
T2-etoposide
anthracyclines
inhibitx txn/replication
e.g. dauxorubicin
BCR-ABL1 fusion protein function
tyrosine kinase ability
PARP inhibitors
PARP (DNA damage repair) inhibition leads to double strand break
BRCA mutation in cancer cells die while normal cells survive
distributional selectivity
useful for drugs equally toxic to host and parasite > selective parasite accumulation/ limited compartment/
plasmodium life cycle
asexual reproduction
gametocyte development
RBC penetration
4-aminoquinolones
accumulates in parasitic lysozomes, inhibiting digestion of host Hb
resistance in efflux of drugs from cells
quinine methanols
binds to malarial pigment haemozoin >intercalates into DNA
erythrocytic
:)chloroquine resistance treatment
8-aminoquinolones
radical cure
metabolised in liver
cytotoxic derivatives
haemolytic anaemia
anti-folates
prophylactic
DNA synthesis inhibition
activated by CYP2C19/ cycloguanil