Representative Drugs Flashcards
Acetylcholine
-Muscarinic agonist
ACh is the primary transmitter of all preganglionic neurons.
- NT in all PSNS postganglionic neurons is Acetylcholine
- SNS postganglionic sweat glands also release ACh for thermoregulation purposes, but that’s it.
- Included in cholinergic pharmacology
Used for intraocular miosis during surgery
Muscarine
- Muscarinic agonist
Muscarine is an exogenous drug that binds to the muscarinic receptor.
- Although it has no chiral carbons, it does have a fixed stereochemistry when it binds to the muscarinic receptor, and that’s what synthetic drugs try to mimic when targeting the muscarinic receptor.
Pilocarpine
- M3 agonist
This has 2 5-membered rings, but still binds to muscarinic receptor. This stimulates the contraction of the ciliary muscle, thus increasing the outflow of aqueous humor and decreasing intraocular pressure.
This is good for patients with glaucoma, and for treating Xerostomia (dry mouth, cottonmouth) & Sjogren’s syndrome (salivary gland secretion reduced).
Use caution if patient has cardiac disease or asthma.
Bethanechol
- Muscarinic agonist
Resembles ACh, but has less AChE hydrolyzation due to carbamate and b-methyl group.
Good for patients needing GI stimulation or treatment of urinary retention.
Use caution if patient has cardiac disease or asthma.
Carbachol
- Muscarinic agonist
Resembles ACh, but has less AChE hydrolyzation due to carbamate.
Good for ocular surgery and glaucoma.
Use caution if patient has cardiac disease or asthma.
Methacoline
- Muscarinic agonist
Resembles ACh, but has less AChE hydrolyzation due to methyl group.
Good to use as provocative test for hyperreactive airways
Use caution if patient has cardiac disease or asthma.
Edrophonium
- Reversible anticholinesterase inhibitor
Edrophonium is very short acting. This has a quaternary amine and an -OH on the aromatic ring.
Used in the diagnosis of Myastenia Gravis (MG), which is an autoimmune disorder that causes muscle weakness due to the loss of skeletal muscle nicotinic receptors.
Neostigmine
- Reversible anticholinesterase inhibitor
This has a quaterenary amine and is a carbamate.
Used for MG & reversal of the nondepolarizing neuromuscular blockage and post-up urinary retention
Physostigmine
- Reversible anticholinesterase inhibitor
Physostigmine has CNS access due to no quaternary amine.
Used for glaucoma, Alzheimer’s disease, and as an antidote to anticholinergic overdose.
Pyridostigmine
- Reversible anticholinesterase inhibitor
Pyridostigmine has a quaternary amine and a carbamate.
Used in treatment of MG, reversal of nondepolarizing neuromuscular blockade, and pretreatment for potential nerve gas exposure (MOA is to occupy AChE so that the nerve gas has nowhere to go).
Echothiophate
- Irreversible anticholinesterase inhibitor
This has a quaternary amine and a S-P bond.
This was used in treatment of glaucoma because it enhances the activity of muscarinic receptors.
Sarin
- Irreversible anticholinesterase inhibitor
This has a P-F bond.
This is a nerve gas, so it’s used as a poison.
Malathion
- Irreversible anticholinesterase inhibitor
This has an S-P bond and kinda acts like a prodrug.
Malathion is used as an insecticide because it’s not toxic in mammals, due to it being inactivated very quickly by carboxyesterases.
Nicotine
This is an exogenous compound that binds to the nicotinic receptor (nicotinic agonist).
At low doses, this stimulates the reticular activating system and releases dopamine (addictive). At higher doses, this causes CV effects like HTN and tachycardia. At toxic doses, it can cause seizures, GI disturbance, etc.
Varenicline
- Partial agonist of nicotinic receptor
This produces a low to moderate release of dopamine that rewards the brain, which reduces withdrawal syndromes. It also blocks the binding of nicotine and therefore blocks the positive reinforcement.
This is great for smoking cessation
Scopolamine
- Muscarinic antagonist (3º amine)
Scopolamine resembles atropine, but is more lipophilic.
This is used to treat GI/urinary conditions, Motion sickness, and as an adjuct for Parkinsons.
This should not be used for ocular applications due to the long duration of effect.
Ipratropium
- Muscarinic antagonist (4º amine)
Ipratropium has a quat. amine, but other than that it really mimicks atropine.
This is used for COPD and occasionally for asthma. It’s an M3 antagonist, so it blocks the ACh-mediated constriction and opens the airways.
Tolterodine
- Muscarinic antagonist (3º amine)
Looks kinda like atropine, but has 2 aromatic rings and no ester.
This is used to treat overactive bladder.
Atropine
- Muscarinic receptor antagonist
Has BBB access because it’s only a 3º amine.
This is used in combination with 2-PAM to treat organophosphate toxicity. This works because it blocks the muscarinic receptors so that all the excess ACh can’t keep activating them.
At different doses, atropine is used for different things: OTC cold remedy, opthalmic exams or procedures, COPD and asthma, reduce urinary frequency, anti-motion sickness & anti-parkinson’s.
Also used as a treatment to cholinergic side effects, like salivation, lacrimation, urination, and defecation (SLUD)
Pralidoxime (2-PAM)
- AChE inhibitor antidote
This is great for pesticide or nerve gas poinsoning. The O- is a strong nucleophile that hydrolyzes the organophosphate.
This doesn’t cross the BBB, so it needs to be combined with atropine.
Succinylcholine
- Nicotinic antagonist (neuromuscular blocking agent)
This displays a depolarizing blockade, meaning it first activates, then blocks the nicotinic receptor. It is essentially an ACh dimer.
It’s used for skeletal muscle relaxation during anesthesia and for electro-convulsant therapy.
This is bad for pts with HTN because this can raise blood pressure. Also bad for pts with hyperkalemia because it can cause cardiac arrest.
Tubocurine
- Nicotinic antagonist (neuromuscular blocking agent)
Tubocurine has a really bulky structure, but has a few components that makes it bind to the nicotinic receptor.
This displays a non-depolarizing blockade, meaning it binds and then blocks the active site of the nicotinic receptor.
This is used for skeletal muscle relaxation during anesthesia, so it’s great for pts who need to be intubated.
Hexamethonium
- Ganglionic nicotinic receptor antagonist
This blocks all SNS and PSNS activity. It was originally used to treat hypertension, but it causes so many adverse effects that it’s not used anymore.
Problems:
Sweat glands (SNS) - decreases perspiration
Heart rate (PSNS) - tachycardia
Other glands (PSNS) - dry mouth, decreased secretions
Eye (PSNS) - pupillary dilation and blurred vision
Blood vessels (SNS) - hypotension
Gut (PSNS) - constipation
Bladder (PSNS) - urinary retention
Botulinum Toxin
- Blocks ACh release
This inhibits the fusion and depolarizing of the synaptic vessel, thus relaxing (paralyzing) the muscle.
Clinically, it’s used for dystonias, cerebral palsy, spasms of ocular muscles, anal fissures, and hyperhidrosis.
Epinephrine
- α1, α2, β1 and β2 agonist
Leads to vasoconstriction (a1), cardiac stimulation (b1), and vasodilation (b2).
This is used for anaphylaxis, glaucoma, and in combination with local anesthetics.
Norepinephrine
- α1, α2, and β1 agonist
Leads to vasoconstriction -> rise in BP (a1); Stimulates heart by increase in force and contraction (b1).
This is used as a pressor (increase BP)
Dopamine
- D1 and β1 agonist at low doses, α1 agonist at high doses.
Leads to vasodilation in renal, mesenteric, and coronary arteries, thus increasing blood flow (D1); Cardiac stimulation (b1); @ high dose -> Vasoconstriction (a1).
Used during shock and useful for acute congestive heart failure.
Cocaine
- Norepinephrine transporter inhibitor
Actually kind of looks like atropine. This blocks the reuptake of NE.
This can be used as a local anesthetic for nasal mucosa and vasoconstriction.
This is bad for HTN pts and has high addictive potential.
Methylphenidate
- NET inhibitor
Blocks NE and DA reuptake transporters, thus enhancing NE and DA signaling.
Used for ADHD and narcolespy, just like amphetamine.
Atomoxetine
- NET inhibitor
Enhances NE levels by inhibiting NET.
Used for ADHD
Amphetamine and methamphetamine
- Indirect acting sympathomimetic
Has no -OH on the aromatic, no β-OH, but it does have an α-methyl.
This is used for ADHD, narcolepsy, and as an anorexiant.
This is potentially dangerous for those with HTN or addiction problems.
Ephedrine/Pseudoephedrine
- Indirect acting sympathomimetics
No -OH on the aromatic. There is an α-methyl group, which protects against MAO, making this orally available.
Pseudoephedrine is used as a nasal decongestant.
Ephedrine doesn’t have any PDA approved uses.
This is bad for patient with HTN and for patients taking an MAO-inhibitor.
Metyrosine
- Indirect adrenergic inhibitor
This inhibits Tryosine -> Dopa, thus inhibiting the formation of all neurotransmitters.
Can be use in preoperative pheochromocytoma treatment
Phenylephrine
- α1 receptor agonist
Norepinephrine with just one -OH on the aromatic ring.
Used for mydriasis without paralysis of the ciliary muscle, to raise blood pressure, and as a nasal decongestant.
Not good if pt already has HTN.
Clonidine
- α2 agonist
Clonidine is an imidazolidine, which lowers the pKa and gives it CNS access.
Used to treat HTN, opiate withdrawal, and ADHD.
Brimonidine
- α2 agonist
This doesn’t look much like NE. It has 3 rings and an attached Br.
Can be used to inhibit the production and increase the outflow of aqueous humor, thus decreasing intraocular pressure.
This is great for patients with glaucoma.
Methyldopa
- α2 agonist
This is a prodrug that when active, acts at the a2 receptors to decrease sympathetic outflow.
Used to treat hypertension, especially during pregancy.
Isoproterenol
- Non-selective direct acting β agonist
Has a bulky group attached to the amine and a catechol.
Used to treat asthma, COPD, and as a cardiostimulant.
This shouldn’t be used if the pt has HTN, because it will increase the cardiac output.
Dobutamine
- Mixed β1 and α1 agonist
Has a long bulky group as the R group, but doesn’t have the β-OH group. Also it’s a catechol (COMT).
One enantiomer is potent for b1, and the other enantiomer is more potent for a1. This results in a positive inotropic effect on the heart with little chronotropic effect.
This is used for acute heart failure and shock.
Albuterol
- β2-selective agonist
Has a bulkly R group and hydroxymethyl group, which makes it selective for b2.
Causes bronchodilation, so it’s used to treat asthma and COPD.
Terbutaline
- β2-selective agonist
Has bulky R group and resorcinol on the aromatic ring, making it b2 selective.
Used as a tocolytic, meaning it relaxes the uterus during premature labor.
Mirabegron
- β3 agonist
Long and bulky R group and no -OH on the aromatic ring.
Used for overactive bladder.
This shouldn’t be used if the pt has HTN.
Phenoxybenzamine
- non-selective α antagonist (irreversible)
Haloalkylamine. This results in a covalent bond, making it an irreversible inhibitor.
Used to treat pheochromacytoma and for hypertensive crisis.
Phentolamine
- non-selective α antagonist (reversible)
Imidazoline. Competitive blocker.
Used to treat pheochromacytoma, male impotence, and for hypertensive crisis
This cannot be used for HTN because although it’s a potent vasodilator, the baroreflex causes tachycardia.
Prazosin
- α1 antagonist
Quinazoline ring + acyl moiety.
Used to treat HTN, Reynaud’s disease, and benign prostatic hypertrophy.
Tamsulosin
- α 1A blocker
Derivative of phenylethylamine.
This is very selective to the prostate urethra, because that area is rich in alpha1A receptors. This drug is less prone to induce hypotension (like Prazosin would).
Propranolol
- non-selective β blocker
Aryloxypropanolamine with a tert-butyl. This is liophilic and bulky, making it selective for the β receptors.
Used for HTN, angina, cardiac arrhythmias, migraine, stage fright, thyrotoxicosis, glaucoma, and CHF.
This shouldn’t be used for pts who have asthma, because it’ll antagonist the bronchodilation effects of the β2 receptor.
Also be sure to taper the dose when D/C due to potential rebound HTN.
Timolol
- Non-selective β antagonist
Has a thiadiazole nucleus with morpholine ring.
Used to treat glaucoma mainly, HTN, angina, and migraine.
This shouldn’t be used for pts who have asthma, because it’ll antagonist the bronchodilation effects of the β2 receptor. Also be sure to taper the dose when D/C due to potential rebound HTN.
Metoprolol
- selective β1 antagonist
Has bulky R group and the single aromatic ring with a para group. This makes it selective to β1, and therefore it’s referred to as “cardioselective.”
Used for HTN, angina, antiarrhythmic, CHF.
Carvedilol
- mixed adrenergic receptor antagonist (β and α1 blocker)
This is an aryloxypropylamine. The β-blocking activity prevents the reflex tachycardia that’s normally associated with α1 receptor antagonists.
Carvedilol is used for HTN and CHF.
Labetalol
- mixed adrenergic receptor antagonist (β and α1 blocker)
This is a phenylethylamine derivative. The β-blocking activity prevents reflex tachycardia normally associated with α1 receptor antagonists.
This is used to treat HTN and hypertensive crisis.
Reserpine
- Catecholamine depleter
This structure is aromatic and extremely bulky. It blocks VMAT, thus depleting the vesicular pool of NE (and all catecholamines).
This is used in the treatment of HTN, but not very common due to adverse effects.