| Question | Answer |
| Reversible AChE Inhibitors | 1.Physostigmine.
2.Neostigmine.
3.Edrophonium.
4.Edrophonium + Atropine.
5.Pyridostigmine.
6.Ambenonium.
7.Donepezil.
8.Tacrine.
9.Rviastigmine.
10.Galatamine. |
| Reversible AChE Inhibitors: Physostigmine | 1.Mech of action: ALL cholinergic synapses, slows AChE so ACh remains longer, Dec IOP.
2.Boiav: Lipid soluble/crosses BBB.
3.used to treat miotic glaucoma & reverses antimuscarini effects.
4.Adverse effects: Asystole, seizures, Resp problems. |
| Reversible AChE Inhibitors: Neostigmine | 1.Mech of action: Mainly Nm receptors in NMJ than ANS ganglia, Inc muscle strength (if too long: muscle weakness b/c no repolariz).
2.Bioav: Quaternary ammonia compound.
3.Used to treat post-op urinary retention & abdominal distention, Myasthenia gravis |
| Reversible AChE Inhibitors: Edrophonium | 1.Mech of action: reversible AChE inhibitor at NMJ (Inc muscle strengthh).
2.Bioav: Short (less potent than neostigmine).
3.Used to asses adequacy of neo/pyridostigmine, differentiate b/w Myasth Gravis or cholinergic crisis |
| How is Edrophonium used to asses Neostigmine dosage in Myasthenia Gravis patients? | Pt is weak, give Edrophonium:
1.If Inc or no change in Weakness: neostig dose is too HIGH.
2.If Dec in Weakness, neostig dose is too LOW |
| Reversible AChE Inhibitors: Pyridostigmine | 1.Mech of action: reversible AChE inhibitor at NMJ, direct action of Nm receptors (Inc muscle strength).
2.Quaternary ammonia compound.
3.Myasthenia gravis. |
| Difference in treatment time using Neostigmine, Edrophonium, & Pyridostigmine | 1.Neo: lasts 2-4hrs.
2.Edroph: lasts 3-4min (IV only).
3.Pyrido: lasts 3-6hrs (XR lasts 12 hrs).
**short half-life decreases side effects. |
| Reversible AChE Inhibitors: Ambenonium | Mechanism of action: Reversible AChE inhibitor. |
| Reversible AChE Inhibitors: Donepezil | 1.Mech of action: reversible AChE inhibitor slows AChE activity.
2.Bioav: Works in CNS.
3.Used to treat Alzheimer's Disease |
| Reversible AChE Inhibitors: Tacrine | 1.Mech of action: reversible AChE inhibitor slows AChE activity.
2.Bioav: Works in CNS.
3.Used to treat Alzheimer's Disease |
| Reversible AChE Inhibitors: Rivastigmine | 1.Mech of action: reversible AChE inhibitor slows AChE activity.
2.Bioav: Works in CNS.
3.Used to treat Alzheimer's Disease |
| Reversible AChE Inhibitors: Galantamine | 1.Mech of action: reversible AChE inhibitor slows AChE activity.
2.Bioav: Works in CNS.
3.Used to treat Alzheimer's Disease |
| What is the ultimate effect of all reversible AChE inhibitors? | Prolonged ACh activity.
**the Inhibitors take several hours for AChE to hydrolyze |
| Which reversible AChE inhibitor will have Inc CNS side effects? | Physostigmine, b/c it is lipid soluble and can cross the BBB. |
| 2 reversible AChE inhibitors that have a direct action on Nm receptors | 1.Neostigmine.
2.Pyridostigmine.
**Both used to treat MG.
**NOT lipid soluble |
| 2 drugs used to treat Post-op abdominal distention & urinary retention? | 1.M3 Agonist: Bethanechol.
2.Reversible AChE Inhibitor: Neostigmine |
| Why are reversible AChE inhibitors better at treating MG than M3 agonist? | B/c AChE inhibitors allow for that NMJ contraction ONLY when the brain wants it to happen instead of a generalize NMJ contraction thoughout the body |
| Would you use Edrophonium for chronic muscle weakness (ex: MG)? | NO, it is IV only and only lasts 3-4mins |
| Why does too much neostigmine cause muscle weakness? | Depolarization blockade: constant depolarization from ACh activation prevents repolarization which affects ion balances. |
| Irreversible AChE Inhibitors | 1.Echothiophate.
2.Diisoprophyl fluorophosphates (DFP).
3.Tetraethyl pyrophosphate (TEPP).
4.Parathion.
5.Malathion.
6.Sarin.
7.Soman.
8.Tabun.
**6-8 nerve gas, 3-5 insecticides |
| Adverse Effects of Irreversible AChE inhibitors | 1.Lens Opacities (Echothiophate only).
2.Chronic Neurotoxicity.
3.Cholinergic overstimulation.
4.Cholinergic crisis. |
| Irreversible AChE Inhibitors: Echothiophate | 1.Mech of action: Contracts ciliary m, Inc aq humour outflow, Dec IOP.
2.Bioav: (+) charged, not volatile (preferred over DFP).
3.Used to treat Mitotic glaucoma (LAST RESORT). |
| Irreversible AChE Inhibitors: Diisoprophyl fluorophosphates (DFP) | 1.Mech of action: Contracts ciliary m, Inc aq humour outflow, Dec IOP.
2.Bioav: Highly lipid soluble, volatile.
3.Used to treat Mitotic glaucoma (LAST RESORT). |
| Irreversible AChE Inhibitors: Tetraethyl pyrophosphate (TEPP) | Irreversible AChE inhibitor that is well absorbed in gut, skin, & conjunctiva. Dangerous to humans.
**Organophosphate insecticide |
| Irreversible AChE Inhibitors: Parathion | Not used clinically, accidental poisoning. well absorbed in gut, skin, & conjuctiva.
**Organophosphate insecticide |
| Irreversible AChE Inhibitors: Malathion | 1.Mech of action: detoxed by plasma carboxylesterases.
2.Bioav: well absorbed in gut, skin, & conjuctiva.
3.Used to treat Head lice. |
| Irreversible AChE Inhibitors: Sarin, Soman, & Tabun | Lethal nerve gas AChE irreversible inhibitors |
| Mechanism behind all Irreversible AChE inhibitors? | Irreversibly phosphorylate AChE.
**EX: P-O bond formed by sarin can't be hydrolyzed. |
| Rank toxicities of Malathion, Parathion, & Sarin | Sarin >>>>> Parathion > Malathion. |
| Differentiate b/w Neostigmine, Physostigmine, & Organophosphates | 1.Neo: reversible, does NOT cross BBB.
2.Physo: reversible, DOES cross BBB.
3.Organophosphate: IRreversible, DOES cross BBB. |
| Symptoms of Cholinergic Overstimulation/Crisis | 1.Miosis.
2.Spasm of accomodation.
3.Inc Salivation.
4.Inc Sweating.
5.Bronchoconstriction.
6.Vomiting (GI stim).
7.Diarrhea (GI stim).
8.Bradycardia.
9.Hypotension.
10.Urinary urgency. |
| Pralidoxime (2-PAM) | 1.Mech of action: AChE reactivator.
2.Bioav: NMJ & ANS ganglia effector site.
3.Used to treat cholinergic crisis from organophosphate poisoning. |
| Will 2-PAM prevent cholinergic chrisis from neostigmine overdose? | NO!! it only works on organophosphates by breaking the P=O bond. (Sarin, Soman, Tabun).
**there is a C=O bond with neostigmine. |
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