Drugs list

Question 1

What is the action and some features of acetazolamide?

Answer 1

• Carbonic anhydrase inhibitor , non-competitive.
• Inhibits bicarbonate reabsorption in the proximal tubule, therefore increasing renal bicarbonate loss.
• Increases bicarbonate loss so assists rectification of alkalosis at altitude, allowing ventilatory drive to increase to mitigate hypoxia. Increases rate of acclimatisation.
  
  • Gives a head start to acclimatisation to high altitudes since renal excretion of bicarbonate is required for central chemoreceptor adaptation and this process is usually slow
• Altitude sickness
• Side-effects: mild diuresis, dizziness, tingling

Question 2

What is the action and some features of adrenaline that are relevant to APP?

Answer 2

• Strong beta-adrenoreceptor agonist (also activates alpha receptors)
• Acts as a bronchodilator through actions at beta-2 adrenoreceptors - useful in asthma
• Anaphylaxis - strong vasoconstrictor, counters the systemic vasodilation to prevent vasodilatory shock
• Need to consider that administration of adrenaline can result in hypokalaemia
  
  • Causes a transient hyperkalemia followed by hypokalemia:
    • This is due to the fact that it is a non-selective adrenergic agonist
    • The hyperkalemia is due to it acting on alpha receptors
    • The hypokalemia is due to it acting on beta-2 receptors

Question 3

What is the action and some features of aminophylline?

Answer 3

• Part of the xanthine/methylxanthine class of drugs.
• Phosphodiesterase III inhibitor , inhibits cAMP breakdown so amplifies effect of β-adrenoreceptor stimulation.
• Used to treat asthma, acutely. Used in hospitalsintravenously when asthma is so severe salbutamol cannot reach the airways.
• Requires close monitoring of heart as has systemic sympathetic side effects eg. increased heart rate, output, blood pressure, arrhythmia, chest pain etc etc

Question 4

What is the action and some features of amlodipine?

Answer 4

• Dihydropyridine VGCC inhibitor.
• On spec, for hypertension.
• Passive systemic vasodilation.
• Appears to cause selective vasodilation of afferent arteriole in kidney, preserving GFR as not to increase renin release.

Question 5

What is the action and some features of aspirin that are relevant to APP?

Answer 5

• Antipyretic action
  
  • Through inhibition of prostaglandin synthesis, is able to reduce body temperature
  • Inhibition of the enzyme cyclooxygenase (COX), preventing the synthesis of inflammatory prostaglandins (including PGE2), which will lead to raised body temperature set points in the anterior hypothalamus
  • PGE2 acts on E2 receptors in the anterior hypothalamus to raise the set point of body temperature
• Recent studies on the mechanism of action have revealed effects independent of COX inhibition as well

Question 6

What is the action and some features of atenolol?

Answer 6

• Selective β1-adrenergic antagonist; cardioselective.
• Used in hypertension. This is primarily as they reduce RAAS activation - reduce peripheral vasoconstriction and fluid retention.
  
  • Also reduce sympathetic drive to reduce CO and thus MAP.
• Used in heart failure. This is to reduce sympathetic drive to reduce myocardial oxygen consumption.
  
  • Also reduce RAAS activation - reduce peripheral vasoconstriction, reduce afterload.

Question 7

What is the action and some features of atracurium?

Answer 7

*Neuromuscular blocking agent used as an adjuvant for general anaesthesia.
*It is a non-depolarising skeletal muscle relaxant (competitively binds w/ cholinergic receptor)

Question 8

What is the action and some features of atropine?

Answer 8

• Muscarinic antagonist.
• On spec - adjuvant in anaesthesia to reduce glandular secretions eg. saliva.
• Also can be given during anaesthesia to treat bradycardia.

Question 9

What is the action and some features of beclomethasone?

Answer 9

• Steroid - synthetic glucocorticoid.
• Acts at nuclear glucocorticoid receptors, reduces phospholipase A2 synthesis.
• Reduces synthesis of lipid mediators of inflammation - prostaglandins, leukotrienes, platelet activating factor.
• On spec, inhaled as chronic treatment for asthma (oral if severe).
• Side-effects - increased risk of infections (esp respiratory infections if inhaled), hyperglycaemia, sodium/fluid retention, hypertension.

Question 10

What is the action and some features of bendroflumethiazide?

Answer 10

• Thiazide diuretic.
• Treatment of hypertension. Increases fluid loss at kidney by inhibiting NCC in distal tubule, to treat volume hypertension.
• Treatment of congestive heart failure - relief of oedema by fluid loss and vasodilation. However, reducing circulating volume activates SNS and RAAS, increasing myocardial O2 demand and worsening problem. Now rarely used.
• Tends to lose effectiveness over time.
• Side-effects: hypokalcaemia, metabolic alkalosis, hypercalcaemia, hyperuricaemia.

Question 11

What is the action and some features of bupivacaine?

Answer 11

• VGNaC inhibitor. Used as a local anaesthetic.
• On spec as adjuvant for general anaesthesia.
• They can be used for post-operative pain relief

Question 12

What is the action and some features of dexamethasone?

Answer 12

• Steroid - synthetic glucocorticoid.
• Acts at nuclear glucocorticoid receptors, reduces phospholipase A2 synthesis.
• Reduces synthesis of lipid mediators of inflammation - prostaglandins, leukotrienes, platelet activating factor.
• Reduces inflammation and oedema.
• Reduces oedema in high-altidude pulmonary oedema and high-altitude cerebral oedema.
  
  • Exact method by which this is beneficial in HACE is not known
• (Prostaglandins sensitise C-fibre pain neurons, so reduces inflammatory pain. Analgesic)
• Side-effects:
  
  • Immune depression, susceptibility to infection
  • Hypertension - action at mineralocorticoid receptor, sodium/fluid retention
  • Bone resorption, diabetes, peptic ulcers, impaired skin healing

Question 13

What is the action and some features of digoxin?

Answer 13

• Cardiac glycoside, inhibits Na+/K+-ATPase.
• Used as a cardiac inotrope (positive) in treatment of heart failure. Said to increase contractility without O2 demand but trials have had mixed results.
  
  • Result in increased intracellular sodium and thus increased extrusion in exchange for calcium. This leads to increased contractility.
• Clinically, most commonly used in treatment of atrial fibrillation.
• Very narrow therapeutic window. Can cause arrhythmia, loss of appetite, nausea.
• Contraindictions - kidney failure, acute MCI, vfib.

Question 14

What is the action and some features of doxazosin?

Answer 14

• α1-adrenergic antagonist.
• Used to cause systemic vasodilation in hypertension.
• However, can inhibit baroreceptor reflex by preventing constriction of lower vessels - orthostatic hypotension, fainting.

Question 15

What is the action and some features of furosemide?

Answer 15

• Loop diuretic. Inhibits NKCC.
• Treat hypertension but thiazide diuretics are more commonly used.
  
  • May be used when tolerance is mounted against thiazides so a stronger diuresis is needed.
• Treatment of congestive heart failure - relief of oedema by fluid loss and vasodilation.
  
  • However, reducing circulating volume activates SNS and RAAS, increasing myocardial O2 demand and worsening problem.
  • Electrolyte disturbances also increase risk of MCI.
  • Now rarely used, apart from one-off injection for acute pulmonary oedema after MCI.
• Also, ototoxic in high doses.
• Side-effects: hypokalcaemia, metabolic alkalosis, hypocalcaemia, hyperuricaemia.

Question 16

What is the action and some features of glyceryl trinitrate?

Answer 16

• Nitric oxide donor.
• Used as a vasodilator in acute hypertensive emergencies and reducing angina.

Question 17

What is the action and some features of glycopyrrolate?

Answer 17

• Antimuscarinic.
• Used in anaesthesia to reduce salivary secretions and control bradycardia.

Question 18

What is the action and some features of ibuprofen, including those relevant to APP?

Answer 18

• Cyclooxygenase I and II reversible, competitive inhibitor.
• Reduces synthesis of prostaglandins, reduces inflammation.
• Prostaglandins sensitise C-fibre pain neurons so aspirin reduces inflammatory pain. NSAID.
• Given after surgical procedures or even preemptively to reduce pain.
  
  • ​Adjuvant drug in general anaesthesia
• Side-effects: risk of GI bleeding, rash, gastric reflux

Question 19

What is the action and some features of ipratropium (bromide)?

Answer 19

• Non-specific muscarinic antagonist, so a bronchodilator.
• Parasympathetic antagonist, used in acute treatment of asthma. Short-acting, given by inhaler.
• It is usually used when there the sympathetic treatments are ineffective

Question 20

What is the action and some features of isoflurane?

Answer 20

• Inhaled (gaseous) general anaesthetic. Lipophilic.
• Hypothesised to act by altering membrane fluidity, and binding to and affecting intramembranous portions of ion channels.
• Mostly used for maintenance of anaesthesia.
• Side-effects:
  
  • Sensitises heart to adrenaline - arrhythmia
  • Respiratory depressant
  • Reduces MAP

Question 21

What is the action and some features of lidocaine?

Answer 21

• VGNaC inhibitor. Used as a local anaesthetic.
• On spec as adjuvant for general anaesthesia.
  
  • Used for post-operative pain relief

Question 22

What is the action and some features of losartan?

Answer 22

• Competitive angiotensin II AT1 receptor antagonist.
• Used in hypertension. Reduces vasoconstriction, aldosterone release and ADH release.

Question 23

What is the action and some features of morphine?

Answer 23

• Opioid used as an analgesic.
• Acts centrally at the µ opioid receptor, inhibits transmission of nociceptive information in the spinal cord as well as causing analgesia by acting directly on the brain eg. PAG.
  
  • Used both during and after surgery
• Causes constipation, itchiness and nausea. Addictive - dependence issues.
• Reversed using naloxone

Question 24

What is the action and some features of naloxone?

Answer 24

• Antagonist of the µ-opioid receptor.
• Used to reverse opiate overdose.

Question 25

What is the action and some features of neostigmine?

Answer 25

* **Anticholinesterase**. * Increases ACh concentration in the synaptic cleft. Used at the **end of anaesthesia** to reverse neuromuscular blockade. * Adjuvant drug during general anaesthesia

Question 26

What is the action and some features of nifedipine?

Answer 26

* Dihydropyridine **VGCC inhibitor** (relaxes smooth muscle). * 1) **Hypertension**. * Passive systemic vasodilation. * Appears to cause selective vasodilation of afferent arteriole in kidney, preserving GFR as not to increase renin release. * 2) **High-altitude pulmonary oedema**. * Condition is caused by heterogeneous hypoxic pulmonary vasoconstriction, so drug acts to reduce the vasoconstriction.

Question 27

What is the action and some features of odansetron?

Answer 27

* Highly specific **5-HT3 antagonist**. * **Antiemetic**. Used **after** **general anaesthesia** or as **adjuvant** to **cytotoxic chemotherapy**

Question 28

What is the action and some functions of phenylephrine?

Answer 28

* **α1 agonist**. Acts as a **vasoconstrictor**. * Used to manage **hypotension in general anaesthesia**.

Question 29

What is the action and some functions of prazosin?

Answer 29

* **α1-adrenergic antagonist**. * Used to cause systemic **vasodilation in hypertension**. * However, can inhibit baroreceptor reflex by preventing constriction of lower vessels - orthostatic hypotension, fainting.

Question 30

What is the action and some functions of propofol?

Answer 30

* **Intravenous general anaesthetic**. * Acts by **potentiating GABA_A** (γ-aminobutyric acid type A) **receptors**. * The binding site is located within the β subunit at the interface between the transmembrane domains and the extracellular domain and lies close to known determinants of anaesthetic sensitivity * Target controlled infusion (TCI) systems are used to administer TIVA in the UK and Ireland. Avoidance of Accidental Awareness during general Anaesthesia (AAGA) * Prinicpally works as a hypnotic, so requires analgesics (opoids) and muscle relaxants. * Short acting. * Most commonly used **induction agent** by far.

Question 31

What is the action and some features of propranolol?

Answer 31

* Nonspecific β-adrenergic antagonist. * Used in heart failure. * This is to reduce sympathetic drive to reduce myocardial oxygen consumption. * Also reduce RAAS activation - reduce peripheral vasoconstriction, reduce afterload. * Contraindictions - asthma, as it is a β2-antagonist so exacerbates bronchoconstriction.

Question 32

What is the action and some features of ramipril?

Answer 32

* ACE inhibitor. * Used in hypertension to reduce ATII-mediated vasoconstriction, aldosterone-mediated sodium and fluid retention and ATII-mediated ADH release. * Used in heart failure to reduce the increased afterload caused by RAAS activation. * Pro-drug converted in the body: ramipril to ramiprilat

Question 33

What is the action and features of salbutamol?

Answer 33

* Specific **β2-adrenergic agonist**. * PKA phosphorylates and activates Na+/K+-ATPase. * Increases K+ sequestering, used to treat acute **hyperkalaemia** along with calcium gluconate, insulin and dextrose. * Used as a **bronchodilator** for treatment of acute asthma. * Side-effects: headache, shakiness, nervousness, dry mouth.

Question 34

What is the action and features of sevoflurane?

Answer 34

* **Inhaled (gaseous) general anaesthetic**. Lipophilic. * Hypothesised to act by altering membrane fluidity, and binding to and affecting intramembranous portions of ion channels. * Mostly used for **maintenance of anaesthesia**. * Side-effects: * Sensitises heart to adrenaline - arrhythmia * Respiratory depressant * Reduces MAP

Question 35

What is the action and some features of spironolactone?

Answer 35

* **Potassium-sparing diuretic** - competitive **antagonist** of **aldosterone mineralocorticoid receptor**. * Used for **hypertension**, decreases sodium and fluid retention so useful for volume hypertension. * Used for **heart failure**. Probably as **diuretic**. Better results than RAA antagonists and pure diuretics. Likely that elevated aldosterone is major driver of deterioration in chronic ischaemic heart failure. * Side-effects: drowsiness, light-headedness.

Question 36

What is the action and some features of suxamethonium?

Answer 36

* **Depolarising blocker** at the NMJ. **nAChR agonist**. * Used to relax the larynx in **intubation**. * Also ensure a more reliable paralysis

Question 37

What is the action and some features of temazepam?

Answer 37

* Binds to specific binding site on GABA_A channel. **Increases open probability** when GABA bound, so **potentiates GABA transmission** - positive allosteric modulator. * Used as a hypnotic to treat **insomnia**. * Used as a sedative and to **reduce** **anxiety** before surgery, and as a **sedative** in ICUs. * Anxiolytic adjuvant to general anaesthesia