Final Flashcards
How do depolarizing neuromuscular blockers work?
Initially work normally, initiating muscle contraction from Na channels. But continued stimulus increases the resting membrane potential, making the channels refractory and unable to open.
Succinylcholine, nicotine
How doe non-depolarizing neuromuscular blockers work?
Simply stops Na channels from opening. Nicotinic competitive antagonist
Pancuronium
What are neuromuscular blockers used for?
Muscle relaxation during surgery
What is needed for a muscarinic agonist?
Charged N with 3 methyl groups
5 atoms long
CH3 aliphatic substitution by double bonded O to resist acetylcholinesterase (orally activity)
CH3 or NH2 on end by double bonded O
Which muscarinic agonists aren’t orally active?
Acetylcholine and Carbachol
What is methocholine? What is it used for?
Muscarinic agonist, test for asthma
What is bethanechol? What is it used for?
Muscarinic agonist used to increase urinary output after surgery or in prostatic hypertrophy that doesn’t respond to tamsulosin
What is pilocarpine? What is it used for?
Muscarinic agonist used as eye drops for glaucoma. Trans isomer
What are the characteristics of a drug necessary for optimal BBB crossing?
Mostly unionized at pH 7.4 (quaternary amides will not cross)
Molecular weight
What is edrophonium? What is it used for?
An anticholinesterase used as a test for myasthenia gravis
Competitive reversible, doesn’t covalently bind
What is neostigmine? What is it used for?
An anticholinesterase used in anesthesia. Reversibly alkylates AChE (~30 minutes)
Covalently binds but doesn’t permanently inactivate
What is pyridostigmine? What is it used for?
An anticholinesterase that reversibly alkylates AChE used to treat myasthenia gravis
Covalently binds but doesn’t permanently inactivate
What is myasthenia gravis?
A neuromuscular disorder with production of antibodies to ACh receptors that leads to a decrease in receptor density at the NMJ, less infolding and bigger gap between nerve fibre and receptor causing less muscle contraction
How can Alzheimer’s be treated?
Anticholinesterases (Rivastigmine, Galantamine, Donepezil)
Donepezil and galantimine don’t covalently bind, rivastigmine do but don’t permanently inactivate
What are some examples of organophostphate anticholinesterases? What are they used for?
Sarin as a toxic nerve gas
Parathion and Malathion as an insecticide
Hydrophobic, covalently bind and permanently inactivate
What is cyclopentolate? What is it used for?
Antimuscarinic used as eye drops prior to eye surgery to cause pupil dilation
What are antimuscarinics used for urinary incontinence?
Tolterodine and Oxybutynin
What is given in organophosphate anticholinesterase toxicity?
2-PAM
What is benztropine? What is it used for?
An atropine like antimuscarinic used to counteract “Parkinsons-like symptoms” from the treatment of schizophrenia
What is scopalamine? What is it used for?
An atropine like antimuscarinic used for motion sickness
What is hyoscine? What is it used for?
An atropine like antimuscarinic used to stop GI spasms that produce abdominal pain
What atropine like antimuscarinics are used to treat COPD?
Ipratropium and Tiotropium
What characteristics make ipratropium and tiotropium good as an inhaler?
Positively charged N decreases systemic absorption from the lungs and prevents crosses of the BBB
What are the 3 ways that the signal or noradrenaline is eliminated from the synapse?
Reuptake at the synapse
COMT (Phase II metabolism enzyme, adds methyl group in meta position to reduce activity) why not orally available
MOA (Phase I metabolism enzyme, removes N to eliminate activity, replaces with double bonded O)
How is adrenaline synthesized?
Tyrosine to DOPA to Dopamine to noradrenaline to adrenaline
How do amphetamine and amphetamine like drugs work?
Cause the release of NA and dopamine from the synapse by binding to and inhibiting MAO which increases [MA], blocks VMAT2 which takes MA up into vesicles, competitively blocks the reuptake of NA, DA and serotonin by being uptaken by the same transporter, leaving high concentrations of the neurotransmitters in the synapse, so high that the reuptake pump begins to work in the opposite direction, pumping MA and all the neurotransmitters out into the synapse