Cardiovascular, PNS, and SNS Drugs Flashcards

Vocabulary flashcards covering cardiovascular drugs (angina, hypertension, hypercholesterolaemia, hypertriglyceridaemia) and drugs affecting the Peripheral Nervous System (PNS) and Sympathetic Nervous System (SNS), based on lecture transcripts.

Angina Pain Cause

Myocardial ischaemia leading to the accumulation of $K^+$, $H^+$, adenosine, and other waste products, which stimulate nociceptors.

Organic Nitrates (e.g., Glyceryl Trinitrate)

Drugs that interact with thiol groups on enzymes to release NO, which interacts with Guanylate cyclase to increase $cGMP$, promoting dephosphorylation of myosin light chain and reducing preload and afterload.

Methaemoglobinaemia

A potential adverse effect of organic nitrates such as Glyceryl Trinitrate.

$\beta$-Adrenoceptor Antagonists ($\beta$-Blockers)

Drugs ending in -olol that block cardiac $\beta_1$-adrenoceptors, inhibiting adenyl cyclase and decreasing $cAMP$ and $PKA$ activity to reduce heart rate and contractility.

Calcium Channel Blockers (CCBs)

Drugs that bind to the $\alpha_1$-subunit of L-type $Ca^{2+}$ channels to prevent extracellular $Ca^{2+}$ entry, thereby reducing heart rate, contraction, and atrioventricular conduction.

Phenylalkylamine (e.g., Verapamil)

A class of calcium antagonists that mainly affects the heart, resulting in reduced heart rate and contractility.

Dihydropyridine (e.g., Nifedipine)

A class of calcium antagonists that mainly acts on vascular smooth muscle to cause arteriolar vasodilation.

Benzothiazepine (e.g., Diltiazem)

A class of calcium antagonists that affects both the heart and blood vessels, providing intermediate cardiac slowing and vasodilation.

Reflex Tachycardia

A rapid fall in blood pressure that activates baroreceptors and the sympathetic nervous system, often observed with dihydropyridines like Nifedipine.

Nicorandil

A potassium channel activator that opens $K_{ATP}$ channels, causing $K^+$ efflux and membrane hyperpolarisation to reduce cardiac excitability and induce vasodilation.

ACE Inhibitors

Drugs ending in -pril that inhibit Angiotensin-converting enzyme, preventing the formation of angiotensin II to cause vasodilation and reduce aldosterone release.

Angio-oedema

An adverse effect of ACE inhibitors characterized by swelling of the lips, eyes, tongue, and throat.

ARBs / Sartans

Angiotensin $AT_1$ receptor antagonists used as a substitute for ACE inhibitors, specifically when patients develop a troublesome cough.

$\alpha_1$-Adrenoceptor Antagonists

Drugs (ending in -osin or -amine) that block vascular $\alpha_1$-adrenoceptors, preventing sympathetically mediated vasoconstriction and reducing peripheral resistance.

Thiazide Diuretics

Drugs that bind to the $Cl^-$ site of the $Na^+/Cl^-$ cotransport system in the distal tubule, increasing excretion of electrolytes and water.

Statins

HMG-CoA reductase inhibitors that decrease hepatic cholesterol synthesis and increase surface expression of LDL receptors, lowering plasma LDL by 30$-$50\%. product examples include Simvastatin.

Rhabdomyolysis

A rare adverse effect of statins involving rapid skeletal-muscle breakdown.

Bile-Acid Resins (e.g., Cholestyramine)

Drugs that bind bile acids in the intestinal lumen to prevent reabsorption, leading the liver to use cholesterol to produce more bile acids and increasing LDL removal from plasma.

Ezetimibe

A prodrug that inhibits the NPC-1L1 transport protein on the brush border of enterocytes, reducing dietary and biliary cholesterol absorption.

PCSK9 Inhibitors

Monoclonal antibodies (ending in -comab) that prevent the breakdown of LDL receptors, thereby increasing hepatic LDL uptake.

Fibrates

Agonists for $PPAR\alpha$ that stimulate lipoprotein lipases to increase triglyceride hydrolysis and decrease hepatic VLDL production.

Atropine

A tertiary ammonium muscarinic receptor antagonist derived from deadly nightshade that reduces parasympathetic activity, including exocrine secretions and GIT motility.

Hyoscine

A tertiary ammonium muscarinic antagonist used as an antiemetic to prevent or treat motion sickness.

Pirenzepine

A quaternary ammonium muscarinic antagonist that does not have actions in the CNS due to its high charge.

Hexamethonium

A nicotinic receptor antagonist that reduces transmission through autonomic ganglia by interfering with ACh release from preganglionic neurons.

Pilocarpine

A muscarinic receptor agonist used in eye drops to treat glaucoma by causing pupil constriction and lowering intraocular pressure.

Methacholine

A muscarinic receptor agonist used to help diagnose asthma by inducing bronchial sensitivity.

Hemicholinium

A cholinergic neuron blocker that blocks the choline carrier, preventing choline uptake into the nerve terminal for ACh synthesis.

Vesamicol

A drug that blocks the active transport of ACh into synaptic vesicles by the vesicular acetylcholine transporter (VAChT).

Botulinum Toxin

A toxin derived from Clostridium botulinum that cleaves SNARE proteins to prevent the exocytosis of ACh vesicles, causing flaccid paralysis.

Edrophonium

A short-acting ($90$ seconds to $2$ minutes) acetylcholinesterase inhibitor used for the diagnosis of Myasthenia Gravis.

Organophosphates (e.g., Ecothiopate, Sarin)

Irreversible acetylcholinesterase inhibitors that form a covalent bond with the enzyme site, leading to ACh accumulation and SLUDGEMS symptoms.

Pralidoxime

An antidote for organophosphate poisoning that uses an oxime group to lure away the phosphate group from the serine hydroxyl group of acetylcholinesterase.

Tricyclic Antidepressants (e.g., Desipramine)

NET inhibitors that block the re-uptake of NA into neural cells, increasing SNS activity and alertness.

MAO-A Inhibitors (e.g., Clorgyline)

Drugs that block the breakdown of NA and serotonin, used primarily for depression.

MAO-B Inhibitors (e.g., Selegiline)

Drugs that block the action of MAO-B enzymes to increase dopamine levels, used in Parkinson's Disease treatment.

Amphetamine

An indirect-acting sympathomimetic amine that displaces NA from vesicles into the cytosol, from where it escapes into the synaptic cleft via carrier-mediated diffusion.

Rhinitis Medicamentosa

Rebound nasal congestion caused by the prolonged use of intranasal alpha-agonist decongestants like Ephedrine or Oxymetazoline.

Pseudoephedrine

An oral non-selective $\alpha_1$-adrenoceptor agonist used as a nasal decongestant by inducing vasoconstriction in the nasal mucosa.