Autacoids, Adrenergic & Cholinergic Pharmacology

Vocabulary flashcards covering key terms in autacoid pharmacology, NSAIDs, adrenergic and cholinergic drugs, their receptors, mechanisms, effects, and clinical uses to aid exam preparation.

Autacoid

Locally-acting biological mediator (e.g., eicosanoids, histamine) that modulates inflammation, pain, vasomotor tone, etc.

Eicosanoid

Lipid-derived autacoid synthesized from arachidonic acid; includes prostanoids, leukotrienes, lipoxins, thromboxanes.

Prostanoid

Eicosanoid subgroup comprising prostaglandins (PGs) and prostacyclin (PGI₂); mediates vasodilation, pain, fever, uterine tone.

Leukotriene (LT)

Eicosanoid produced via 5-lipoxygenase pathway; strong chemoattractant, increases vascular permeability, bronchoconstricts.

Thromboxane A₂ (TXA₂)

Platelet-derived prostanoid that triggers vasoconstriction and platelet aggregation via Gq-coupled receptors.

Cyclo-oxygenase-1 (COX-1)

Constitutive enzyme forming homeostatic PGs; inhibition causes GI toxicity but yields antiplatelet effect.

Cyclo-oxygenase-2 (COX-2)

Inducible enzyme generating inflammatory PGs; selective inhibition gives anti-inflammatory benefit but ↑thrombotic risk.

Phospholipase A₂ (PLA₂)

Enzyme liberating arachidonic acid from membrane phospholipids; upstream target of corticosteroids.

Corticosteroid (SAID)

Glucocorticoid receptor agonist that indirectly blocks PLA₂, broadly suppressing eicosanoid synthesis and inflammation.

Non-steroidal anti-inflammatory drug (NSAID)

Reversible competitive inhibitor of COX-1/COX-2 producing analgesic, antipyretic, anti-inflammatory effects.

Aspirin (acetylsalicylic acid)

Irreversibly acetylates COX-1/COX-2; low dose antiplatelet, high dose anti-inflammatory; GI, ototoxic, Reye’s risks.

Misoprostol

PGE₁ analogue given with NSAIDs to replace gastro-protective prostaglandins and prevent ulcers.

Acetaminophen (Paracetamol)

Weak COX inhibitor at peroxidase site; strong antipyretic/analgesic, minimal anti-inflammatory; dose-dependent hepatotoxic.

Ibuprofen

Non-selective COX inhibitor with balanced analgesic, antipyretic, anti-inflammatory actions and relatively mild GI/CNS effects.

Diclofenac

NSAID inhibiting COX and lipoxygenase; potent anti-inflammatory plus free-radical reduction.

Ketorolac

Potent parenteral NSAID used post-operatively for opioid-level analgesia; notable renal toxicity risk.

Indomethacin

Very potent COX/PLA₂ inhibitor; reduces neutrophil migration; CNS & GI adverse effects limit use.

Coxib

Selective COX-2 inhibitor (e.g., celecoxib) offering strong anti-inflammatory effect but increasing thrombotic events.

General NSAID GI Toxicity

Nausea, dyspepsia, erosions, ulcers, bleeding due to COX-1–mediated loss of gastric protection.

Alpha-1 (α₁) receptor

Gq-coupled adrenergic receptor; postsynaptic vasoconstriction, mydriasis, glycogenolysis, ↓insulin.

Alpha-2 (α₂) receptor

Gi-coupled autoreceptor; presynaptic inhibition of NE release; central activation lowers sympathetic outflow.

Beta-1 (β₁) receptor

Gs-coupled cardiac receptor; ↑chronotropy, ↑inotropy, ↑renin release, raises blood pressure.

Beta-2 (β₂) receptor

Gs-coupled receptor causing broncho-/vasodilation and hepatic glycogenolysis; high affinity for adrenaline.

Beta-3 (β₃) receptor

Adrenergic receptor that stimulates lipolysis and relaxes bladder detrusor muscle.

Adrenaline (epinephrine)

Endogenous catecholamine; non-selective α/β agonist; used for anaphylaxis, CPR, asthma, local vasoconstriction.

Noradrenaline (norepinephrine)

Catecholamine acting on α₁, α₂, β₁; potent vasoconstrictor for septic shock, causes reflex bradycardia.

Dopamine

Dose-dependent agonist (D₁ < β₁ < α₁); low doses renal vasodilation, higher doses inotropic, very high vasoconstrictive.

Dobutamine

Predominant β₁ agonist with some α/β₂ activity; short-term inotrope for acute heart failure.

Ephedrine

Mixed α/β agonist releasing stored catecholamines; bronchodilator, nasal decongestant, CNS stimulant.

Amphetamine

Indirect agonist that releases NE/DA/5-HT; CNS stimulant used for ADHD, narcolepsy; strong abuse potential.

Methamphetamine

More lipophilic amphetamine analogue; powerful CNS stimulant/euphoriant with significant neurotoxicity.

Methylphenidate

DAT/NET reuptake inhibitor; mild stimulant used in ADHD and narcolepsy.

Reserpine

VMAT inhibitor that depletes catecholamines from vesicles, lowering sympathetic tone.

Entacapone

Peripheral COMT inhibitor prolonging catecholamine (esp. L-DOPA) action in Parkinson’s therapy.

Clonidine

Partial α₂ agonist; lowers BP and mitigates withdrawal by decreasing sympathetic outflow.

Guanfacine

Selective α₂ agonist; antihypertensive and second-line ADHD drug enhancing prefrontal cortical function.

Guanabenz

Central α₂ agonist with antihypertensive and neuroprotective effects in multiple sclerosis research.

Methyldopa

Pro-drug converted to α-methylnorepinephrine (α₂ agonist); drug of choice for hypertension in pregnancy.

Prazosin

Selective α₁ blocker; treats hypertension, BPH, PTSD nightmares; risk of first-dose orthostatic hypotension.

Terazosin

Longer-acting α₁ blocker than prazosin; used for hypertension and BPH.

Doxazosin

Highly selective α₁ antagonist with 20-h half-life; antihypertensive/BPH agent.

Salbutamol (Albuterol)

Short-acting β₂ agonist (SABA) inhaled for acute asthma and COPD bronchodilation.

Orciprenaline (Metaproterenol)

Short-acting β₂ agonist producing broncho- and vasodilation.

Salmeterol

Long-acting β₂ agonist (LABA) with 12-24 h duration for maintenance asthma/COPD therapy.

Formoterol

Rapid-onset LABA for long-term asthma/COPD control.

Mirabegron

β₃ agonist that relaxes bladder detrusor muscle; indicated for overactive bladder, may raise BP.

Propranolol

First-generation non-selective β-blocker; treats HTN, angina, arrhythmias; can cause bronchospasm, mask hypoglycemia.

Alprenolol

Non-selective β-blocker with partial agonist (ISA) activity; similar uses to propranolol.

Oxprenolol

Non-selective β-blocker with ISA; fewer metabolic side effects but still bronchoconstrictive.

Atenolol

Second-generation selective β₁ blocker; hydrophilic, less CNS entry; used for HTN, angina.

Practolol

Selective β₁ antagonist (now rarely used) with similar profile to atenolol but notable adverse ocular effects historically.

Metoprolol

Third-generation highly β₁-selective blocker without ISA; penetrates CNS; cornerstone in CHF, MI, HTN.

Botulinum toxin

Blocks ACh vesicle exocytosis at cholinergic terminals, causing flaccid paralysis; used cosmetically & for spasticity.

Vesamicol

Inhibits VAChT, preventing ACh storage in vesicles and reducing cholinergic transmission.

Neostigmine

Reversible AChE inhibitor that augments NMJ transmission; treats myasthenia gravis; quaternary, no CNS entry.

Physostigmine

Reversible AChE inhibitor that crosses BBB; used for glaucoma and antimuscarinic antidote.

Edrophonium

Very short-acting AChE inhibitor (10-20 min) used to diagnose myasthenia gravis (Tensilon test).

Organophosphate

Irreversible AChE inhibitor (nerve agent/pesticide) causing cholinergic crisis and death without antidote.

Methacholine

Short-acting non-selective cholinergic agonist used by inhalation to diagnose bronchial hyperreactivity in asthma.

Carbachol

Potent, long-acting mixed N/M agonist resistant to AChE; used topically for glaucoma.

Pilocarpine

Tertiary muscarinic agonist that increases exocrine secretions and lowers intraocular pressure.

Betanechol

Selective muscarinic agonist stimulating GI and bladder smooth muscle; treats postoperative urinary retention.

Atropine

Non-selective competitive muscarinic antagonist; increases heart rate, dries secretions, antidote for organophosphates.

Scopolamine

Muscarinic antagonist with prominent CNS effects; used for motion sickness and postoperative nausea.

Ipratropium

Inhaled M₃ antagonist producing bronchodilation with minimal systemic absorption; for COPD/asthma.

Hyoscine Butylbromide (Buscopan)

Peripheral M₁ antagonist used as antispasmodic for GI/urinary smooth muscle cramps.

Pirenzepine

Selective M₁ antagonist that decreases gastric acid secretion; investigational for peptic ulcer therapy.

Nicotine

Full nicotinic agonist producing CNS stimulation and addiction plus peripheral sympathomimetic effects.

Varenicline

Partial α4β2 nicotinic agonist that reduces craving and reward during smoking cessation.

Trimetaphan

Short-acting nicotinic ganglionic blocker used IV to produce controlled hypotension in surgery.

Mecamylamine

Oral ganglionic blocker; historical antihypertensive now studied for nicotine dependence.

Tubocurarine

Prototype non-depolarizing NMJ blocker causing skeletal muscle relaxation; releases histamine → hypotension.

Succinylcholine

Depolarizing NMJ blocker producing rapid sequence paralysis; risk of malignant hyperthermia and hyperkalemia.