Neuro Drugs 2 Flashcards
Acetazolamide
- Inhibits CA used to treat open angle and closed angle glaucoma
- Decreaes HCO3 and decreases humor production
- Causes metabolic acidosis and alkalinization of urine
Epinephrine
- Constriction via alpha 2 leading to decreased humor production
- S/E is myadriasis, blurry vision, optic pruritis, can precipitate closed angle glaucoma
Brimonidine
- Alpha 2 agonist leads to decrease B2 activation and decreased humor production
- Causes
Litanaprosct
-PGF2a agonist causes opening of canals and increased flow
Pilocarpine, carbachol, physostigmine, ecothiophate
- Cholinergic agonists cause contriction of pupillary and opening of angle
- DOC in closed angle glaucoma
- Cholinergic S/E, miosis, cyclospasm (Ciliary muscle paralysis)
Timlol
- Beta antagonist leads to decreased humor production
- No effect on vision
Opiod
- Mu is morphine, kappa is enkephalin, dela is dynoprhin
- All work to open Cl and decrease Ca and NT release in pain neurons (inhibiitory interneurons)
- Leads to decreasd Pain
- Can also be used to treat diahrrea (Loperamide, diphenoxylate) Cought (Dextromethophan), acute pulmonary edema
- Methadone has a longer half life and can be used to decrease addiction, Naloxone combined with buprenoprhine can do the same thing
- S/E: respn depression, constipation, miosis
- Overdose treat with naloxone (competetive antagonist of mu R)
Butorphanol
- Partial mu agonist and kappa agonist used to treat chornic pain with fewer S/E
- Partial agonist activities can precipitate withdrawl
Tramadol
- Partial mu agnost and also seretonoin and other effects
- Used in chronic pain to cause fewer S/E
- Lower siexure threshold is major S/E
Partial Siezures
- First line is carbemezapine
- Also phenytoin, valproate, new drugs, all but bezos and ethosuximide
Complex
- First line is phenytoin, carbemezapine, valproate
- Other new drugs can be used (lamotragine, topiramate, gabapentin, etc)
Absence
Ethosuximide first and Valproate second (T type Ca)
Status Epilepticus
Benzos are given for aute phase also IV phenytoin
Phenytoin
- Use dependent Na channel block, also inhibits glutamate release
- Use in simple and complex siezures and also for status
- S/E: Gingival Hyperplasia, Fetal hydantoin (neural tube defects, heart defects, cleft lip, microcephaly), Hirsuitism, Megaloblastic Anemia (folate), SLE like syndrome, ataxia, diplopia
Carbemezapine
- Similiar to phenytoin, Except add agranulocytosis and aplastic anemia to list
- DOC for partial siezures, SIADH
- All epileptic drugs could cause stevens johsnons (Fatigue and fever followed by mucosal desquamating rash and epidermal necrolysis at Epi/dermal junction)
Valproate
- Multiple, Na, increase GABA, T type Ca
- Second line for absence, second line for partial, first line for diffuse
- Causes neural tube defects, fatal hepatotoxicity, weight gain
Ethosuximide
- DOC for absence siezures, blocks T type Ca channels
- Stevens Johsnons and GI, uticaria
Phenobarbtol
- DOC for pregnancy and children, protein binding limits transplacental transfer
- Causes GABA duration increase leading to potentiation
- S/E: Resp depression, P450 inducer
Lamotrigne
Na channel blocker
-Second line for complex and partial, minimal S/E
Gabapentin
V gated Ca channels
Can be used in siezures, but often used in peripheral neural pain syndromes
Topirimate
- Increase GABA and decrease Na
- Second line siezure and prophylaxis for migranes
- S/E: kidney stones and weight loss
Tiagabine, Vigaartin
- Tiagabine blocks GABA uptake, second line for partial
- Vigabatrin blocks GABA deamination, second line for partial
Levitracetam
-Unkown mechanism , scond line for parital and diffuse
Barbs
-Bind to GABAa receptor and increase duration of opening leading to increased Cl Flux
-Leads to depression of neural signals
-Siezures (phenobarbitol), anesthesiaamnesia (Thiopental, decreased T1/2)
S/E: Respiratory depresion, inducers of P450s
-Contraindicated in porphyria
Benzos
- GABAa inreased frequency of opening, decreased S/E, reversed by flumezanil
- Used as amnestic, anxiolytic. Anterograde amnesia
- Used in status, DT, secondary to MgSO4 for ecplamptic siezures
- S/E: Resp depression in the context of alcohol
- Long is Diazepam (Metabolized to active)
- Med (Lorazepam)
- Short (Triazolam)
- US (Midazolam)
- Often used in anesthesia protocol
Z Drugs
- Milder side effects because of shorter half life and not metabolized to active products when compared to benzos.
- Used as sleep aid
Inhaled Anesthetics
- Speed of induction is inversely proportional to blood solubility. N2O is minimally bloo soluble leads to rapid iduction while halothane is highly lipid soluble and leads to slow induction.
- MAC minimum Concentration to anesthetize 50% of population. Inversely correlated to potency. High potency halothane has low MAC while low potency N2O has high MAC
- Increase Cerebral Blood flow but decrease demand
N2O
Rapid induction, not blood soluble. Need high MAC
-Can cause gas expansion and spontaneous abortions
Halothane
- Potent, low MAC but slow indcution
- Can cause hepatic necrosis days after surgery
Other S/e
Methoxyflurane is nephrotoxic
- Enflurane is proconvulsant
- All can cause malignant hyperthermia excpet N20 due to genetic mutation in RyR
Barbituates
- Thiopental, IV
- Highly lipid soluble, rapid induction, but also rapidly redistributes to fat leading to rapid stop of function
- Decrease Cerebral Blood Flow
Benzos
- Most common is midazolam which is ultra short acting, combined with oiods and inhaled
- Anterograde amnesia
- Post surgical decrease in Resp/BP, tx with flumezanil
ketamine (Arylcyclohylamines)
- NMDA receptor antagoinst
- Leads to dissociative amnesia, hallucinations, bad dreams
- Commonly used for short procedures in kids like bone setting
- Increase Cerebral Blood flow, don’t use in trauma
Propofol
- GABAa potentiator
- Rapid induction and rapid recvery with minimal post surgical N/V
Local Anestetics
- Esthers: CocaIne, (Slow acetylators, increase hypersensitivity, PABA cross react)
- Amides: LIdoaIne
- Present in uncharged amine form that enters cell, then protonated and blocks Na channels from inner membrane in a use dependent fashion
- Blockage occurs from small to large diameter neurons. Pain, Temp, Touch, Pressure, and rarely motor
- Often administered with epinephrine or alpha agonist to constrict vessels and maintain high local concentration
- If infected and acid tissues will stay in charged amide form and can’t enter cell, more is needed
- S/E is Arryhtmias, BP Changes, and cardiotox
Succinylchline
- Depolarizing neuromuscular blocker leads to depolarization of membrane and stuck in that state. Binds tighly to AchR
- Phase I is complete depolarization and no antidote is possible, treatment with AchEI will potentiate block
- Phase 2 is repolarization, but desensitization. Tx with AchEI can lead to recovery
- S/E: Hyper Ca, and K. Also malignant hyperthermia, treat with dantolene
Tubocurarine (Curium)
- Used in intubaion, non depolarizing
- AchR antagonist leads to blockage of receptors
- Antidote is AchEI (Neostigmine and edrophonium)
Dantrolene
-Prevents Ca release from SR used in malignant Hyperthermia caused by succinylcholine or typical antispychotics
Parkinsons Basics
- Decreasd DA leads to bradykinesia
- Increased Ach leads to tremor and rigidity
DA agonists
- Bromocriptine
- Repriridne, paramexole (preferred)
Increase DA centrally
- Carbidopa/L-Dopa: L Dopa can cross BBB and be converted into DA by L-Dopa decarboylase
- Carbidopa prevents peripheral conversion via AAAD (Leads to increase Central effects and decreasd peripheral effects)
- Dosing problems leads to akinesia and dyskinesia
- Also arrytjmias from peripheral effects
Increase DA release
-Amantadine: Causes DA release, also antiviral against rubella and influenza
Prevent DA breakdown
-MAO-B inhibitor prevents DA breakdown with minimal effect on MAO-A (Decrease risk of tyramine induced hypertensive crisis or seretonin syndrome)
Entacapone, Tolcapone
-Prevent the conversion of L-Dopa to 3-O-mehtyldopa (inactive) by COMT
Benztropine
- Muscarinic antagonist
- Curbs elevated Ach leads to improvment in tremor and rigidity
- Causes anticholinergic S/E (Angle closure glaucoma)
Memantine
-NMDA receptor antagonist, used to inhbit ecititoxicity in Alzhiemers
Donepazil, galantamine, rivastigmine
-Central AchEI
Huntingtons
- Increased DA and decreased GABA/Ach
- Haloperidol blocks D2 Receptors
- Reserpine, blocks VMAT mediated loading of DA into vesiceles
Sumitriptan
- Seretonin analog used in abortive treatment of cluster and migrane headaches
- Causes vasoconstriction and decreasd trigeminal activation
- Contraindicated in patienst with prinmetal angina, may also precipitate hypertensive crisis (sereTONIN)
- Short T1/2
Propsognosia
-Inability to recognize the meanings and associations of objects. Propsognosia. Associaed with infarction in Occipitotemporal association corticies (MCA)
