Block 32 Pharm Flashcards
Antacids and alginates examples
- Magnesium trisilicate
- Aluminium/magnesium mixtures (Maalox) - Alginates
what are antacids and alginates used for?
dyspepsia, GORD
Mag trisillicate mechanism?
-antacid
- inc pH of gastric juicr via neutrilisation
CI of magnesium triscillicate?
Hypophosphataemia
mag tricillicate interactions?
- amlodepine
- nifedipine
- verapamil
mag trisillicate side effects?
- diarrhoea
- nephrolithiasis (long term use)
Co-magaldrox (Maalox) mechanism?
- mix of mag hydroxide and al hydroxide
- neutralises acid
Co-magaldrox indications?
dyspepsia
Co-magaldrox side effects?
constipation and diarrhoea
Co-magaldrox and renal impairment?
There is a risk of accumulation and aluminium toxicity with antacids containing aluminium salts
alginates mechanism?
- reacts w gastric acid to form a raft of alginic acid gel
- raft had a neutral pH
- acts as a barrier to impede reflux
CI of alginic acid?
- intestinal obstruction
- where excessive water loss likely (e.g. fever, diarrhoea, vomiting, high room temperature)
alginates and renal impairment?
avoid - risk of hypernatremia
alginic acid (gaviscon) side effects?
- ankle swelling
- constipation
H2-receptor antagonists?
rantidine
rantidine indications?
dyspepsia, GORD, peptic ulceration, prophylaxis of NSAID associated peptic ulceration
cautions with H2 receptor antagonits like ranitidine?
signs and symptoms of gastric cancer can be masked
ranitidine side effects?
- bone marrow depression
- nephritis
- acute pancreatitis
- dyskinesia
ranitidine mechanism?
- normally after a meal, gastrin -> histamine release -> H2 activation -> acid secretopm
- ranitidine blocks H2 receptors on gastric parietal cells -> less acid produced
PPIs?
- Lansoprazole
- Omeprazole
PPIs mechanism?
- inhition of the H+/K+/ATPase pump
- inhibition of acid production
PPIs and H pylori eradication?
- PUD associated w H pylori infection
- acid inhibition in H pylori eradication therapy raises gastric pH discouraging growth of H pylori
- PPI inhibit urease enzyme
PPIs indications?
- dyspepsia
- GORD
- oesophagitis
- peptic ulceration
- prophylaxis of NSAID associated peptic ulceration
- H. pylori eradication
cautions of PPIs?
- risk of fractures - high doses in the elderly
- C diff infection risk
- masking gastric cancer symptoms
- B12 abs reduced w long term use
- osteoporosis risk
side effects of all PPIs?
- abd pain
- constipation
- diarrhoea
- headache
- skin reactions
Opiate based anti-motility agents =
codeine
indications of codiene?
- diarrhoea
- short term pain relief
- dry cough
CI of codeine and all opiods?
- ARD
- comatose
- raised ICP
- risk of paralytic ileus
CI for codeine?
- active UC
- ab associated colitis
- children under 18
- known ultra-rapid codeine metabolisers
codeine interactions?
- buprenorphine
- clozapine
- naltrexone
- fluoxetine
side effects of codeine?
- arrhythmias
- constipation
- hallucinations
- nausea and vomiting on initiation
- urinary retention
Non-opiate based anti-motility agents =
loperamide
codeine mechanism?
- mu opiod receptors agonism
- g protein response
- hyperpolarisation of nociceptive neurons -> impaired pain transmission
loperamide mechanism?
- used for diarrhoea
- mu opiod agonist on the circ and longitudinal intestinal muscle
- inhibits release of ACh and prostaglandins -> reducing peristalsis -> inc intestinal transit time
loperamide indications?
- diarrhoea - acute and chronic
- faceal incontinence
loperamide CI?
- Active UC
- ab assoc colitis
- abd distension
loperamide interactions?
- clozapine
cautions of loperamide?
children under 12
side effects of loperamide?
- GI disorders
- headache
- nausea
Aminosalicylates?
- e.g. mesalazine
- IBD
mesalazine mechanism?
- induce and maintains remission
- inhibition of nuclear factor kappa B and blocks production of pro-inflamm cytokines
- blocks COX pathways - less leukotrienes
mesalazine CI?
- blood clotting abn
side effects of aminosalicyclates?
- cough
- fever
- leucopenia
- proteinuria
-*** pancreaTitis ** - ** agranulocytosis**
- peripheral neuropathy
corticosteroids?
Hydrocortisone,Prednisolone, Budesonide
corticosteroids indications?
IBD - Crohs earlier than UC
corticosteroids mechanism?
- neutrophil apoptosis
- inhibits phospholipase A2, and NF-Kappa B
- promote anti-inflammatory genes like IL10
CI for all corticosteroids?
- avoid live viruses
- systemic infection
steroids side effects?
- cushings syndrome
- psychotic disorder
- hirtutism
- HTN
- osteoporosis
- peptic ulcer
- inc weight
steroids and adrenal suppression?
During prolonged therapy with corticosteroids, particularly with systemic use, adrenal atrophy develops and can persist for years after stopping. Abrupt withdrawal after a prolonged period can lead to acute adrenal insufficiency, hypotension, or death
Immunosuppressants =
azathioprine -> Crohns
azathioprine mechanism?
- IS
- Purine synthesis inhibition
- inhibition of B and T cells
azathioprine Cl?
Reduced TPMT activity
azathioprine interactions?
- allopurinol
- BCG vaccine
- captopril
- HZ vaccine
- ACEi
- trimethoprim
azathioprine side effects?
- bone marrow depression
- leucopenia
- pancreatitos
- inc infection risk
- thrombocytopenia
pre-treament screening for azathioprine?
- TPMT activity
- increased risk of myelosuppression with reduced TPMT activoty
azathioprine monitoring?
- FBC weekly for first 4 weeks
- then at least every 3 months
- for risk of myelosuppression
cytokine inhibitors?
- Infliximab
- Adalimumab
cytokine inhibitors Ix?
Crohns
infliximab mechanism?
- binds to TNF-a
-> Downregulation of IL1 and IL6
adalimumab mechanism?
- TNF-a inhibition
CI of infliximab/ adalimumab?
moderate/ severe HF, severe infections
infliximab interactions?
- BCG vaccine
- cholera vaccine
- MMR vaccine
- HZ vaccine
- influenza vaccine
side effects of infliximab?
- alopecia
- arrhythmias
- hypotension/ hTN
- neutropenia
- vasodilation
- sepsis
pre-Tx screening w infliximab/ adalimumab?
TB
adalimumab side effects?
- agranulocytosis
- anx
- haemorrhage
- leucopenia, neutropenia, thrombocytopenia
adalimumab is assoc w ?
infections, sometimes severe, including tuberculosis, septicaemia, and hepatitis B reactivation.
Metronidazole & Vancomycin are used for
C diff assoc diarrhoea - colitis
metronizadole mechanism?
- high activity against anaerobic bacteria and protozoa
metronidazole interactions?
- disulfiram
- fluorouracil
- lithium
- warfarin
side effects of metronidazole - IV?
- Vomiting
- metallic taste
- nausea
- dry mouth
- vomiting
rare side effects w metronidazole
- panc
- agranulocytosis
- peripheral neuropathy
- cerebellar syndrome
metronidazole mechanism?
- nucleic acid synthesis inhibition
- anaerobic bacteria
vancomycin mechanism?
- prevens crosslinkage of peptidoglycan subunits
- prevents cell wall formation
- glycopeptide ab
cautions of vancomycin?
Systemic absorption may be enhanced in patients with inflammatory disorders of the intestinal mucosa or with Clostridioides difficile-induced pseudomembranous colitis (increased risk of adverse reactions)
side effects of vancomycin?
- agran
- eosinophilia
- hypersensitivity
- renal failure
Antiprotozoal agent e.g.
metronidazole
anti-fungal agents?
- Nystatin
-Fluconazole
nystatin mechanism?
- forms channels in the membrane
- changes membrane permeability
- affinity for ergosterol
nystatin indications?
- oral candidasis
nystatin side effects?
- abd distress
- angioedema
- face oedema
- SJS
fluconazole mechanism?
- selective inhibitor of P450 dependent enzyme lansterol 14-a demethylase
- this enzyme converts lanosterol to ergosterol, which is necessary for fungal cell wall synthesis
fluconazole Ix?
- candidasis
CI of fluconazole?
acute porphyrias
cautions of fluconazole?
Susceptibility to QT interval prolongation
interactions of fluconazole?
- alc
- amiodarone -> hepatotoxicity
- amphotericin B
- apiprazole
- atorvostatin
- bendroflumethaizide
side effects of fluconazole?
- GI discomf
- diarrhoea
- headache
- skin reactions
- agranulocytosis
- QT prolongation
- torsades
other antispasmodics?
Mebeverine & Peppermint oil
IBS drugs?
- Mebeverine
- Peppermint oil
- Hyoscine (Buscopan)
hyoscine mechanism?
- muscarinic receptor antagonism
- anticholinergic effect
- relaxes/ spasmolytic effect on SM
Safety info for hyoscine?
- risk of serious adverse effects
- including tachycardia, hypotension, and anaphylaxis
CI for all antimuscarinics?
- closed angle glaucoma
- GI obstruction
- MG
- paralytic ileus
- pyloric stenosis
- severe UC
- significant bladder outflow obstruction
- toxic megacolon; urinary retention
Interactions of hyoscine?
clozapine
side effects of all antimuscarinics?
- const
- dry mouth
- flushing
- dyspepsia
- tachycardia
- urinary retention
mebeverine?
- antispasmodic
- anticholinergic
- relaxes SM
Mebeverine CI?
paralytic ileus
side effects of mebeverine?
- angioedema
- face oedema
- skin reactions
peppermint oil mechanism?
- contains L-menthol
- blocks CC in SM -> antispasmodic effect
- reduces calcium influx
side effects for peppermint oil?
- bradycardia
- GI discomfort
- reflux
- tremor
- paraesthesia
what are the laxatives?
- Methylcellulose
- Ispaghula husk
- Senna Lactulose
- Sodium picosulphate
methylcellulose mechanism?
- bulk forming laxative
- inc water content of stool
- Methylcellulose absorbs water in the gastrointestinal lumen thereby increasing the bulk of the stool.
- This leads to distension and stimulation of peristalsis
isphalga husk mechanism?
- bulk forming
- increasing faecal mass which stimulates peristalsis
CI of isphalga husk?
- faceal impaction
- intestinal obstruction
- undiagnosed rectal bleeding
- reduced gut motility
cautions w isphalga husk?
- adequate fluid intake to avoid oesophageal or intestinal obstruction
side effects of ispaghula husk?
- abd distension
- bronchospasm
- conjunctivitis
senna mechanism?
- stimulant laxative
- stimulates peristalsis thereby increasing the motility of the large intestine.
senna CI?
- atony
- intestinal obs
- undiagnosed abd pain
side effects of senna?
- albuminuria
- fluid imbalance
- GI discomfort
- haematuria
- pseudomelanosis coli
prolonged/ excessive senna use can cause?
hypokalaemia
lactulose indications?
- constipation
- hepatic encephalopathy
lactulose CI?
- galactosaemia
- GI obstruction
- GI perf
side effects of lactulose?
- diarrhoea
- flatulence
- nausea
- vomiting
- abd pain
lactulose mechanism?
- osmotic laxative
- causes retention of water through osmosis leading to softer easier to pass stool
Sodium picosulphate mechanism?
- stimulant laxative
- inhibits abs of water and electrolytes and increases their secretion into intestinal lumen to form an active metabolite which acts directly on colonic mucosa to stimulate peristalsis
CI of Sodium picosulphate?
intestinal obst
side effects of Sodium picosulphate
- diarrhoea
- GI discomfory
summary of the laxatives?
- methylcellulose and ispaghula husk: BF
- senna: faecal softner
- lactulose: osmotic
- Sodium picosulphate: stimulant
Local anaesthetics =
- Lidocaine
- Bupivacaine
- used for suturing
lidocaine CI?
all grades of AV block, severe myocardial depression
SE of lidocaine?
- AV block
- cardiac arrest
- hypotension
- methaemglovinaemia
lidocaine mechanism?
- blocks sodium channels
- preventing nerve depolarisation
bupivacaine mechanism?
- sodium channel blocker
CI of bupivacaine?
- Bier’s block
- injection into inflamed tissues
SE of bupivacaine?
- arrythmias
- dizziness
- hTN
- parasthesia
- neurotoxicity
IV anaesthetics?
- Etomidate
- Ketamine
- Propofol
- Thiopental
What are IV anaesthetics used forr?
Rapid induction of anaesthesia, total intravenous anaesthesia, prolonged sedation
etomidate mechanism?
- short acting IV
- binds to GABA-A increasing duration of time
- post inhib effect of GABA is prolonged
etomidate cautions?
- acute circ failure
- adrenal insufficiency
- hypovolaemia
- cardiovascular disease
etomidate - adrenal insufficiency?
- suppresses adrenocortical function
- should not be used for maintenance of anaesthesia
SE of etomidate?
- hypotension
- resp disorders
- vascular pain
- adrenal insufficiency
Ketamine mechanism?
- rapid acting GA
- NMDA antagonist used for induction of anaesthesia
ketamine CI?
- HTN
- pre-eclampsia
- raised ICP
- stroke
side effects of ketamine?
- anx
- hallucination
- nystagmus
- vomiting
which anaesthetic can cause cystitis haemorrhagic?
ketamine
reducing hallucinations with ketamine?
Incidence of hallucinations can be reduced by premedicaton with a benzodiazepine (such as midazolam).
Propofol mechanism?
- positive modulation of the inhibitory function of GABA-A
propofol indications?
- induction and maintenance of anaesthesia
cautions of propofol?
- shock
- cardiac impairment
- hypovolaemia
- raised ICP
SE of propofol?
- apnoea
- arrhythmias
- hypotension
- nausea and vomiting
what else can occur w propofol?
- pulm oedema
- urine discoloration
- pancreatitis
Thiopental mechanism?
- barbituate
- binds to CI- ionophore at GABA receptor, enhancing effect of GABA
thiopental SE?
- decreased cardiac contractility
- arrhythmia
- circ collapse
- resp disorders
IV opiods during anaesthesia?
- Fentanyl
- Remifentanil
use of iV opiods during anaesthesia?
Reduction in the dose requirement of anaesthetic agents, sedation and respiratory depression during assisted ventilation in intensive care
fentanyl Mx?
- mu opiod receptor agonist
- hyperpolarises cell and inhibits nerve activity
CI of fentanyl?
opiod naive ppts
SE of fentanyl?
- apnoea
- HTN
- muscle rigidity
- resp disorders
Remifentanil mechanism?
µ-opioid agonist with rapid onset and peak effect, and short duration of action.
CI of remifentanil?
analgesia in conscious patients
remifentanil SE?
- Apnoea
- hypotension
- muscle rigidity
remifentanil metabolism?
In contrast to other opioids which are metabolised in the liver, remifentanil undergoes rapid metabolism by plasma esterases; it has short duration of action which is independent of dose and duration of infusion
inhalation anaesthetics =
- Desflurane
- Halothane
- Isoflurane
- Nitrous oxide
- Sevoflurane
Desflurane indications?
indication and maintenance of anaesthesia
CI of all volatile halogenated anaesthetics?
Susceptibility to malignant hyperthermia
side effects of all volatile halogenated anaesthethics?
- agitation
- chills
- resp disorders
- cough
SE of desflurance/
coagulation disorders, conjunctivitis
desflurane mechanism?
- agonises GABA-A and glycine receptors
- antagonises glutamate receptors
Halothane mechanism?
- binds to potassium channels in cholinergic neurons
- binds to NMDA and calcium channels causing hyperpolarisation
SE of halothane?
- hepatotoxicity
- resp depression
- irreg HB
Isoflurane SE?
- Carboxyhaemoglobinaemia
- delirium
- cognitive impairment
isoflurane mechansim?
- binds to GAB receptor, glutamate receptor and glycine receptor
nitrous oxide cautions?
- presence of intercranial air after head injury or trapped air after underwater dive
- pneumothorax
NO interacts w
methotrexate
SE of NO?
- Abd distension
- agranulocytosis
- parasthesia
- subcaute combined cord degeneration
NO mechanism?
- induces opiod release in the brain stem
- activates descending nociceptive process
sevoflurane mechanism?
- GABA and glycine receptors
- inhibt excitatory activity by blocking nictonic ACh, serotonin and glutamate receptors
uses of the inhalational anaesthetics?
Induction and maintenance of anaesthesia
sevoflurane CI?
Susceptibility to QT-interval prolongation
Sevoflurane SE?
- Drowsiness
- fever
- hypothermia
Depolarising neuromuscular-blocking drugs
suxamethonium (succinylcholine)
use of suxamethonium?
Endotracheal intubation, muscle relaxation during surgery or on the ICU
suxamethonium mechanism?
- mimicks ACh at NM junction
- but bc its hydrolsed much slower than ACh, depolarisation is prolonged leading to NM blockade
CI of suxamethonium?
- hyperkalaemia
- low plasma cholinesterase activity - including severe liver dsisease
- malignant hyperthermia
suxamethonium interacts w
steroids - fludrocortisone, hydrocortisone, pred, beclomethasone
SE of suxamethonium?
- arrythymias
- bradycardia
- involuntary muscle contractions
- myogloburia
Competitive N2 receptor antagonists (non-depolarising blockers)
- Atracurium
- Cisatracurium
- Mivacurium
- Pancuronium
- Rocuronium
- Vecuronium
atracurium uses?
NM blockade
cautions for all non depolarising NM blocking drugs?
- burns
- CV disease
- fluid dist
- MG
Atracurium interacts w?
steroids
SE of all ND NM blocking drugs?
- flushing
- hypotension
atraucrium and other non depolarising NM blockers mechanism?
- competes w ACh for binding sites
competitive N2 antagonists (ND NM blockers) are used for…
Endotracheal intubation, muscle relaxation during surgery or on the ICU
acetylcholineesterase inhibitors =
- Edrophonium
- Neostigmine
- Pyridostigmine
edrophonium, neostigmine and pyridostigmine mechanism?
- prolong ACh action
- by inhibiting acetylcholineesterase action
AChE inhibitors are used to treat
- MG, and to
- reverse non depolarising (competitive) NM blockade - neostigmine
CI of all anticholinesterases?
- intestinal or urinary obs
side effects of all anticholinesterases?
- abd cramps
- diarrhoea
- hypersalivation
- nausea and vomiting
Reversal of musle relaxants used during general anaesthesia =
neostigmine
to test the therapeutic response to AChE inhibitors in myasthenia gravis =
edrophonium
drug used for MG =
Pyridostigmine