Top 100 Drugs I Flashcards
How does adenosine treat SVT?
Agonist of adenosine receptors on cell surfaces
Reduces automaticity
Increases AV node refractoriness
Breaks re-entry circuit
What is the mechanism of action of adrenaline?
Potent agonist of alpha 1 and 2 and beta 1 and 2 receptors.
Vasoconstriction of vessels supplying skin, mucosa and abdominal viscera (a1)
Increase HR, contractility and myocardial excitability (b1)
Vasodilatation of vessels supplying the heart and muscles (b2)
Bronchodilation (b2)
Suppression of inflammatory mediators from mast cells (b2)
What are indications for adrenaline?
- Cardiac arrest
- Anaphylaxis
- Local vasoconstriction (reduce bleeding, prolong local anaesthesia)
Treatment of anaphylactic shock in adults and children > 12 y/o?
Adrenaline 500mg IM
Hydrocortisone 200mg
Chlorphenamine 10mg
Important adverse effects of spironolactone?
Hyperkalemia Gynaecomastia Liver impairment Jaundice SJS
Examples of drugs that antacids may interfere absorption?
ACEIs Levothyroxine Bisphosphonates Abx e.g. cephalosporins Digoxin
Important adverse effects of allopurinol?
Skin rash, SJS, TEN
Drug hypersensitivity syndrome
Why does allopurinol increase toxicity of mercaptopurine/azathioprine?
They require xanthine oxidase for metabolism
Indications for aminoglycosides? e.g. gentamicin
Severe sepsis
Pyelonephritis and complicated UTI
Biliary and intra-abdominal sepsis
Endocarditis
Why are streptococci and anaerobic bacteria resistant to aminoglycosides?
Aminoglycosides require an oxygen-dependent transport system to enter bacterial cells, which streptococci and anaerobics lack
What is the MoA of amiodarone?
Blocks sodium, potassium and calcium channels
Antagonism of alpha and beta receptors
Reduces automaticity, slows conduction velocity, increases refractoriness
What are some examples of amiodarone SEs?
Hypotension Pneumonitis, pulmonary fibrosis Bradycardia, AV block Photosensitivity, grey discolouration Cataracts, optic neuritis Thyroid abnormalities
Indications for ACEIs?
Hypertension
Chronic heart failure
Ischaemic heart disease
Diabetic nephropathy and CKD (reduces proteinuria)
What is MoA of ACEI?
Blocks conversion of angiotension I to angiotensin II, which reduces vasoconstriction, reduces production and release of aldosterone and dilates efferent arterioles
Main side effects of ACEIs?
(First-dose) hypotension Dry cough Hyperkalemia Renal failure Angioedema Anaphylactoid reactions
What is the MoA of ARBs?
Blocks action of ATII on AT1 receptor
What are indications for SSRIs?
Moderate to severe depression (and mild depression if psychological tx fails)
Panic disorder
OCD
How are SSRIs different to TCAs?
Both block reuptake of serotonin & similar efficacy
BUT
TCA blocks uptake of noradrenaline and other receptors leading to more SEs and is more dangerous in overdose
Important side effects of SSRIs?
GI upset Appetite and weight disturbance Hyponatremia (especially in elderly) Suicidal thoughts and behaviour may be increased Lowers seizure threshold Prolonged QT interval Bleeding Serotonin syndrome
What is serotonin syndrome?
TRIAD
Autonomic hyperactivity
Altered mental state
Neuromuscular excitation
What happens if patient suddenly stops SSRI treatment?
Withdrawal:
- GI upset
- Influenza-like symptoms
- Sleeplessness
Indications for TCAs?
2nd line for moderate to severe depression
Neuropathic pain e.g. diabetic neuropathy
What is MoA for TCAs?
Blocks reuptake of serotonin and noradrenaline
Blocks wide array of receptors including muscarinic, histamine (H1), alpha 1 and 2 and dopamine (D2) receptors
What are important adverse effects of TCAs?
Antimuscarinic- dry mouth, constipation, urinary retention, blurred vision
H1 and alpha 1 block: sedation, hypotension
Arrhythmias, ECG changes, prolonged QTc, convulsions, hallucinations, sexual dysfunction, extra-pyramidal symptoms
What occurs with a TCA overdose?
EXTREMELY DANGEROUS!
Severe hypotension, arrhythmias, convulsions, respiratory failure
CAN BE FATAL
What is MoA of venlafaxine? and What are the indications?
SNRI (+ weak antagonist of H1 and muscarinic receptors)
Indicated in major depression and generalised anxiety disorder
What is the mechanism of mirtazepine?
Antagonist of inhibitory pre-synaptic alpha2 adrenoceptors
Strong H1 antagonist
When is metoclopramide indicated?
Prophylaxis and treatment of N&V, particularly in reduced gut motility
What is the mechanism of cyclizine/promethazine?
H1 receptor antagonist
Why are H1 blockers contraindicated in hepatic encephalopathy?
Strong sedating effect
Cyclizine has the least sedating effect
What is the mechanism of action of phenothiazines, and give 2 examples!
D2 receptor blockers
Examples: prochlorperazine, chlorpromazine
What is the MAJOR side effect of phenothiazines?
Extrapyramidal syndrome, acute dystonia, tardive dyskinesia
Drowsiness, postural hypotension
What is the main indication for ondansetron/granisetron?
Prophylaxis and treatment of N&V, particularly in context of surgery and chemotherapy
What is the mechanism of action of loperamide/codeine phosphate?
Blocks u-opioid receptors in GIT
and does not cross CNS so no analgesic effects
What drug is 1st line for symptomatic bradycardia?
Atropine
What is hyoscine butylbromide used for?
Palliative- reduce secretions
IBS- reduce peristaltic contraction and smooth muscle tone
What are major side effects of antimuscarinics?
Tachycardia Dry mouth Constipation Urinary retention Blurred vision C/I angle-closure glaucoma Drowsiness Confusion
What is the 1st line drugs for overactive bladder?
Antimuscarinic selective for M3 receptor @ bladder:
Oxybutynin
Solifenacin
Tolterodine
What are major side effects of first generation antipsychotics? (haloperidol, chlorperazine etc.)
Extrapyramidal syndromes NMS QT prolongation Drowsiness and hypotension Erectile dysfunction Hyperprolactinemia
What are the indications for 1st gen antipsychotics?
Psychomotor agitation
Schizophrenia
Bipolar disorder
N&V
What are the major side effects of 2nd gen antipsychotics?
Sedation Extrapyramidal effects Metabolic- weight gain, DM, lipid changes Prolonged QT interval, arrthymias Sexual dysfunction AGRANULOCYTOSIS
What are the indications for aspirin?
ACS and acute ischaemic stroke
Long-term secondary prevention of CV, cerebrovascular and PVD
In AFib if warfarin/NOACs C/I
Mild/moderate pain and fever
What are common sides effects of aspirin?
GI irritation GI ulceration Bronchospasm [prolonged high doses] tinnitus Life-threatening in overdose
What are indications for benzodiazepines?
Seizures/status epilepticus Alcohol withdrawal reactions Sedation for interventions Insomnia Anxiety
What is the MoA of benzodiazepines?
Binds GABAa receptor (chloride channel), which causes it to remain open and makes the cell more resistant to depolarisation.
This causes widespread depressant effect on synaptic transmission.
What are important adverse effects of benzodiazepines?
Dose-dependent drowsiness, sedation and coma
What is the name of the specific antagonist of benzodiazepines?
Flumazenil
What are the indications for beta-2 agonists?
- Asthma
- COPD
- Hyperkalemia
What are important adverse effects of beta-2 agonists?
Tachycardia
Palpitations
Anxiety
Tremor
Why must LABA be given with ICS in asthma patients?
Without a steroid, LABA are associated with increased asthma deaths
What are indications for beta-blockers?
- Ischaemic heart disease
- Chronic heart failure
- Hypertension
- Atrial fibrillation
- SVT
What are the effects of beta-blockers?
Reduces inotropy and chronotropy
Prolongs refractory period of AV node
Reduces renin secretion
What are examples of beta-1 selective beta-blockers?
Atenolol
Bisoprolol
Metoprolol
In what conditions are beta-blockers contraindicated?
Asthma
Heart block
Haemodynamic instability
What are the side effects of beta-blockers?
Fatigue, cold extremities, headache, GI disturbance, sleep disturbance, nightmares, impotence in men
