Pharmacology Flashcards
What is an irreversible side effect of tetracyclines?
Teeth staining
How does montelukast work?
Blocks action of leukotriene D4 in the lungs which decreases inflammation and relaxes smooth muscle
How does rituximab work and what conditions is it used for?
Binds to CD20 on B cells
Used in Hodgkins lymphoma and some vasculitides
How does vigabatrin work?
Analogue of GABA which inhibits GABA aminotransferase (inhibits GABA breakdown)
Has a seizure suppression effect
How does cyclophosphamide work?
Chemotherapeutic agent which causes cell apoptosis when it breaks down to its metabolite phosphoralide mustard
Which chemotherapy agent has the side effect of haemorrhagic cyctitis?
Cyclophosphamide
How does vincristine work?
Vinca alkaloid chemotherapeutic agent which acts through inhibiting microtubule activity
Which chemotherapy drug causes peripheral neuropathy?
Vincristine
How does doxorubicin work?
Anthracycline chemotherapy drug which acts through inhibition of topoisomerase II (allows uncoiling of DNA in preparation for transcription)
Which chemotherapy agent is known to be cardiotoxic?
Doxorubicin
How does blinatumomab work and what is it used for?
Targets the CD19 antigen on B-cells
Used in treatment of refractory B cell leukaemia
Which biological agent works by inhibiting IgE?
Omalizumab
How does inflixamab work?
Inhibits TNF-alpha
Which type of antibiotic is known for its QTc prolongation?
Macrolides
How do PPIs work?
Inhibit the H+-K+-ATP pump in the gastric parietal cells
How does lamotrigine prevent seizures?
Prolongs sodium channel inactivation to prevent membrane depolarisation and subsequent seizure activity
How does metformin work to lower blood sugars?
Decreased gluconeogenesis and increase peripheral utilisation of glucose
How does insulin function to reduce blood sugar levels?
Enhances glucose uptake and cell metabolism
How does gliclazide work to lower blood sugar levels?
Augments insulin secretion from functioning B pancreatic cells
How does risperidone work?
It is a D2, 5-HT, alpha-1, histamine-1 antagonist
How does a n oculogyric crisis present?
Involuntary deviation upward of both eyes
Which type of drugs most commonly cause oculogyric crises?
Neuroleptic drugs
What is the mechanism of action of trimethoprim?
Inhibits an essential step in synthesis of bacterial nucleic acid synthesis
Is an antifolate antibiotic
What is the mechanism of action of gentamicin?
Inhibits bacterial synthesis by binding to 30s subunit of bacterial ribosomes
What is the mechanism of action of clarithromycin?
Inhibits bacterial synthesis by binding to 50s ribosomal subunit
What is the mechanism of action of cyclopentolate?
Muscarinic acetylcholine M1 receptor antagonist
What is the mechanism of action of azithromycin?
Binds to recombinant 23S rRNA of bacterial 50S ribosomal unit to inhibit bacterial synthesis
What is the mechanism of action of metronidazole?
Inhibits bacterial synthesis by causing loss of helical DNA structure and strand breakage
What is the mechanism of action of vancomycin?
Inhibits synthesis of bacterial cell wall via prevention of peptide incorporation into the peptidoglycan matrix
What is the mechanism of action of allopurinol?
Inhibits xanthine oxidase and its active metabolite
What is allopurinol used for in oncology patients?
Used to avoid TLS
What is the mechanism of action of amlodipine?
Inhibits calcium ion reflux at L-type calcium channels
What is the mechanism of action of hyoscine?
Antimuscarinic agent which competitively inhibits acetylcholine muscarinic receptors
What is the mechanism of action of isoprenaline?
Positive inotropic and chronotropic effects via B1 adrenergic stimulation
What is the mechanism of action of adrenaline?
Alpha and beta receptor agonist
B1 receptors - increases HR and myocardial contractility
A-adrenergic receptors - inhibits vasodilation
What is the mechanism of action of atenolol?
Selective B1 receptor antagonist - antagonist to sympathetic innervation
What is the mechanism of action of NAC?
Generates glutathione which in turn conjugates the NAPQI (paracetamol metabolite) into a harmless metabolite
Reduces the circulation of toxic metabolites
What is the mechanism of action of mycophenolate mofetil?
Prevents DNA synthesis and proliferation by inhibiting inosine monophosphate
What is the mechanism of action of flecainide?
Blocks sodium channels which reduce the rate of depolarisation of phase 0 without changing the overall AP duration.
What class of anti-arrythmic is flecainide?
Class Ic
Give an example of a class III antiarrhythmic drug?
Amiodarone
What is the mechanism of action of amiodarone?
Block potassium channels that increase the action potential duration by increasing length of repolarisation in phase 3.
What is an example of a class Ia anti-arrhythmic drug?
Disopyramide
What is the mechanism of action of disopyramide?
Block sodium channels that increase AP duration by increasing length of depolarisation during phase 0
What is the mechanism of action of Ivabradine?
Blocks the If channel in the SAN, reducing rate of pacemaker potential depolarisation, increasing refractory period and slowing the heart rate
What is an example of a class Ib anti-arrhythmic drug?
Mexiletine
What is the mechanism of action of melixetine?
Block sodium channels that shorten the AP duration by reducing the length of plateau in phase 2.
What is the most common side effect of IV quinine?
Tinnitus
What are the major side effects of ciclosporin?
Chronic interstitial nephritis
Hypertrichosis
Periodontal destruction
Which commonly used drug in TB management can reduce the effectiveness of warfarin?
Rifampicin - potent enzyme inducer
Which antibiotic can cause cholestatic jaundice?
Co-amoxiclav
Which chemotherapy agent can cause haemorrhagic cystitis?
Cyclophosphamide
What is the mechanism of action of fexofenadine?
H1 antagonist
What is the mechanism of action of fomepizole?
Competitive inhibitor of alcohol dehydrogenase
What is the mechanism of action of milrinone?
Positive inotrope - competitive phosphodiesterase-3-inhibitor that inhibits degradation of cAMP.
What is the mechanism of action of domperidone?
Dopamine-receptor antagonist
Which antiepileptic medication is associated with visual field defects?
Vigabatrin
What is the mechanism of action of aminophylline?
Inhibits phosphodiesterase type III and IV which breakdown cAMP in smooth muscle cells. Allows bronchodilation.
What is the mechanism of action of chloramphenicol?
Inhibits intracellular protein production
Binds to 50S subunit of 70S ribosome inhibiting action of peptidyl transferase
What is the mechanism of action for ondansetron?
Selective serotonin 5-HT3 receptor antagonist
What is the mechanism of action of verapamil?
Non-dihydropyridine CCB
What is the most common side effect of verapamil?
Constipation
What is the mechanism of action of infliximab?
IgG monoclonal ab which binds to TNF-alpha with high affinity
Which chemotherapeutic agent causes peripheral neuropathy?
Vincristine
Which drug causes “grey baby syndrome”?
Chloramphenicol
What is “grey baby syndrome”?
Cardiovascular collapse in infants due to immature hepatic glucuronidation meaning they are unable to excrete the drug.
Which corticosteroid has the highest mineralocorticoid activity?
Fludrocortisone
What is the mechanism of action of levetiracetam?
Binds to SV2A which regulates release of neurotransmitters into vesicles
What is a type A drug reaction?
“Augmented”
Exaggeration of a drugs normal pharmacological actions
Normally dose dependent
What is a type B drug reaction?
“Bizarre”
Novel response not expected from the known pharmacological actions of teh drug
What is a type C drug reaction?
“Continuing”
Persist for a very long time
What is a type D drug reaction?
“Delayed”
Become apparent sometime after the use of a medicine
What is a type E drug reaction?
“End-of-use”
Associated with medication withdrawal.
What is the mechanism of action of ondansteron?
Serotonin receptor antagonist - selectively blocks 5-HT3 serotonin receptor
What are the common side effects of ondansetron?
Dry mouth
Drowsiness
Constipation
Which antibiotic can cause red man syndrome if it is infused too quickly?
Vancomycin
How does red man syndrome present?
Pruritic erythematous rash over face, neck and upper torso
What is one of the main significant side effects of ethambutol?
Visual disturbances
What is the antidote for benzodiazepine overdose?
Flumazenil
What is the mechanism of action of prednisolone?
Inhibits migration of neutrophils
What is the mechanism of action of cyclizine?
Sedating antihistamine with antimuscarinic properties.
Acts on medulla oblongata
What is the mechanism of action of phenylephrine?
Pure alpha-adrenoreceptor agonis which elevates vascular resistance and increases BP
What is the mechanism of action of sildenafil?
Phosphodiesterase V inhibitor
What is the mechanism of action of insulin?
Translocation of pre-formed GLUT4 to the cell surface
What is nitric oxide often derived from?
L-arginine
What is the mechanism of action of nitric oxide?
Modulation of vascular tone via vasodilation
What is the mechanism of action of ursodeoxycholic acid?
Protects hepatocytes against bile-acid-induced apoptosis
What class of HIV drugs tend to cause lipoatrophy?
NRTIs (nucleoside reverse transcriptase inhibitors) e.g. zidovudine
What is the mechanism of action of indomethacin?
Inhibits prostaglandin E2 synthesis therefore closing the ductus arteriosus
What effects does adrenaline have in the treatment of anaphylaxis?
A1 receptor agonist - vasoconstriction
B1 agonist - increased contractility and HR
B2 agonist - bronchodilation
Which TB drug most commonly causes peripheral neuropathy?
Isoniazid
What is the preferred opioid used in syringe drivers?
Diamorphine - larger doses with smaller volumes compared to morphine
What is the mechanism of action of adenosine?
Blocks the AV node to allow normal heart rhythm to restart
Causes reversible bronchospasm
A1 adenosine-receptor agonist
What is the reason that ACEIs can cause cough as a side effect?
Bradykinin accumulates causing cough through bronchoconstriction
What is the conversion ration from oral morphine to subcutaneous diamorphine?
3mg PO morphine is roughly equivalent to 1mg S/cut diamorphine
What is the mechanism of action of ranitidine?
H2-receptor blocker
What is the antidote to unfractionated heparin?
Protamine
What renal complication can beta-lactam antibiotics sometimes cause?
Acute tubule-interstitial nephritis
What is the mechanism of action of sodium valproate?
Reduction of catabolism of GABA
What is the mechanism of action of isoniazid?
Inhibition of mycolic acid synthesis
What is the mechanism of action of lorazepam?
Activates chloride channels by binding in post-synaptic GABA-A ligand-gated chloride channels and increases flow of chloride ions into the cell
What is the ratio for converting IV to oral morphine?
1mg Iv morphine is roughly equivalent to 2mg PO morphine.
What is the mechanism of action of lidocaine?
Prolongs inactivation of voltage-gated sodium channels, which prevents action potentials from firing
What is the mechanism of action of morphine?
Adenylyl cyclase inhibitor
What treatment is used for malignant hyperthermia?
Dantrolene
What is the mechanism of action of sildenafil?
Phosphodiesterase V inhibitor - causes pulmonary-specific vasodilation and reduction of pressure
What antibiotics are more commonly known to cause erythema multiforme?
Sulphonamides (co-trimox) and penicillin
What is the mechanism of action of ipratropium?
Cholinergic receptor blocker - decreases smooth muscle contraction in the airways
What is the mechanism of action of furosemide?
Blocks sodium and chloride reabsorption in the loop of Henle
Which antibiotics can cause ototoxicity?
Gentamicin
Vancomycin
What is the mechanism of action of acetazolamide?
Reversible inhibitor of carbonic anhydrase
What is the mechanism of action of folic acid?
Activated by dihydrofolate reductase as it itself is biochemically inactive
What blood test should be closely monitored in ganciclovir treatment and why?
FBC as drug can cause leukopenia, neutropenia and thrombocytopenia
What is the mechanism of action of atomoxetine?
Activation of adrenergic alpha and beta receptors
Selective norepinephrine reuptake inhibitor
What is the main renal complication of acetazolamide therapy?
Acute interstitial nephritis
What is the mechanism of action of midazolam?
GABA-A receptor agonist
What is the first line treatment for CMV?
Ganciclovir
What is the mechanism of action of phenylephrine?
Alpha adrenergic effects - increases systemic vascular resistance via vasoconstriction with no effect on HR
What is the mechanism of action of chlorphenamine?
H1-receptor blocker
What is the mechanism of action of dornase alpha?
Endonucleic cleavage of extracellular DNA
What is the mechanism of action of LMWH?
Accelerates antithrombin-dependent inactivation of factor Xa
Which diuretic can cause a metabolic acidosis?
Acetazolamide
Why are statins and macrolides contraindicated to be taken at the same time?
Macrolides are potent CYP450 3A4 inhibitors and as statins are metabolised this way - may cause statin toxicity.
What is the mechanism of action of Ezetimibe?
Blocks the Niemann-Pick C1-like protein and therefore inhibits dietary cholesterol absorption
What is the drug metabolism pathway for carbamazepine?
CYP3A4
What is the mechanism of action of phenobarbital?
Increases opening time of chloride channels by binding to GABA-A receptors
What is the drug metabolism pathway for diazepam?
CYP3A4
What is the drug metabolism pathway for erythromycin?
CYP3A4
What is the drug metabolism pathway for fentanyl?
CYP3A4
What is the drug metabolism pathway for midazolam?
CYP3A4
What is the drug metabolism pathway for nifedipine?
CYP3A4
What is the drug metabolism pathway for ondansetron?
CYP3A4
What is the drug metabolism pathway for rifampicin?
CYP3A4
What is the drug metabolism pathway for caffeine?
CYP1A2
What is the drug metabolism pathway for theophylline?
CYP1A2
What is the drug metabolism pathway for phenytoin?
CYP2C9
What is the drug metabolism pathway for ibuprofen?
CYP2C9
What is the drug metabolism pathway for amitriptyline?
CYP2D6
What is the drug metabolism pathway for codeine?
CYP2D6
What is the drug metabolism pathway for SSRIs?
CYP2D6
What is the drug metabolism pathway for paracetamol?
Glucuronidation
What is the mechanism of action of mannitol?
Osmosis in the proximal renal tubule
Why should methotrexate and NSAIDs be avoided concurrently?
NSAIDs inhibit renal excretion of methotrexate
Which renal side effect is most common with topiramate?
Nephrolithiasis
How can trimethoprim affect U&Es?
As trimethoprim competes with creatinine for secretion into the renal tubule, it can cause asymptomatic elevation in creatinine with no change in urea. It is transient and resolves on cessation
What is the mechanism of action of atropine?
Blocks the vagal impulse
What is the mechanism of action of clindamycin?
Inhibits protein synthesis preventing elongation along peptide chain at the 50S ribosome
What respiratory complication occurs in upto 10% of patients taking long term amiodarone therapy?
Pulmonary fibrosis
What is the mechanism of action of caffeine?
Blocks adenosine receptors causing increased sensitivity to CO2 concentrations, resp centre stimulation and wakefulness
What is the mechanism of action of spironolactone in PCOS?
Antagonism of androgen receptors
Which antibiotic interacts with the OCP to decrease its effectiveness?
Rifampicin
Which receptors does low dose adrenaline primarily act upon?
Beta 1 ++
Beta 2 ++
What is the mechanism of action of desmopressin?
Water reabsorption activator - it is a synthetic analogue of ADH
Increases cellular permeability of collecting ducts resulting in water reabsorption
What is the mechanism of action of sulfasalazine?
Inhibits leukotrienes to reduce inflammation
What is the mechanism of action of alendronic acid?
Inhibits osteoclastic activity thereby increasing bone mass
Which fluid must amiodarone be administered in?
Glucose 5%
What is the mechanism of action of sumatriptan?
5HT-1D and 5HT-1B receptor agonist resulting in vasoconstriction of cranial blood vessels and inhibits release of pro-inflammatory neuropeptides
What is the mechanism of action of oxybutynin?
Muscarinic receptor antagonist - competitive antagonist of acetylcholine at postganglionic muscarinic receptors
Which receptors does high dose adrenaline primarily act upon?
Alpha 1 +++
Alpha 2 +++
Beta 1 +++
Which receptors does noradrenaline primarily act upon?
Alpha 1 ++++
Alpha 2 +++
Beta 1 +++
Which receptors does low dose dopamine primarily act upon?
Beta 1 ++
Which receptors does high dose dopamine primarily act upon?
Alpha 1 +++
Beta 1 +
Which receptors does dobutamine primarily act upon?
Beta 1 ++
What does low-dose adrenaline do to heart rate?
Increases
What does high-dose adrenaline do to heart rate?
Increases
What does noradrenaline do to heart rate?
Increases
What does low-dose dopamine do to heart rate?
Increases
What does high-dose dopamine do to heart rate?
Increases
What does low-dose dopamine do to Contractility?
Increases
What does dobutamine do to heart rate?
Increases
What does low-dose adrenaline do to Contractility?
Increases
What does high-dose adrenaline do to Contractility?
Increases
What does high-dose adrenaline do to SVR?
Increases
What does low-dose adrenaline do to Cardiac output?
Increases
What does low-dose dobutamine do to Contractility?
Increases
What does noradrenaline do to Contractility?
Increases
What does low-dose dopamine do to SVR?
Nil effect
What does low-dose dopamine do to Contractility?
Increases
What does low-dose adrenaline do to SVR?
Decreases
What does noradrenaline do to SVR?
Increases
What does high-dose adrenaline do to Cardiac output?
Nil effect
What does high-dose dopamine do to SVR?
Increases
What does dobutamine do to SVR?
Nil effect
What does noradrenaline do to Cardiac output?
Decreases
What does high-dose dopamine do to Cardiac output?
Decreases
What does low-dose dopamine do to Cardiac output?
Increases
What does dobutamine do to Cardiac output?
Increases
What are the side effects of prostaglandin E1?
Apnoea (most common)
Respiratory depression
Fever
Seizures
Tissue oedema
Cortical hyperostosis
What is the mechanism of action of terlipressin?
Vasopressin analogue
What can cimetidine do to U&Es?
Causes elevation of creatinine without changing GFR - potent inhibitor of tubular creatinine secretion
What is the mechanism of action of flucloxacillin?
Inhibits bacterial cell wall synthesis
What is the mechanism of action of methotrexate?
Dihydrofolate reductase antagonist
What is the mechanism of action of propranolol?
B1 and B2 receptor antagonist
What is the mechanism of action of adalimumab?
TNF-alpha inhibitor
How does a conjugate vaccine work?
Combines a weak polysaccharide antigen with a string protein antigen as a carrier so that a T cell response can be induced
Where is the site of action of furosemide?
Ascending loop of Henle
What is the starting dose (first bag) of NAC in a child >40kg?
150mg/kg in 200ml 5% glucose over 1 hour
What are the side effects of protease inhibitors?
Dyslipidaemia
Insulin resistance and diabetes
Fat accumulation
Lipodystrophy