Pharm 2 - Insomnia, Migraine, Brain Tumors, Anesthetics, Ocular, Epilepsy, Vertigo Flashcards
Mediator of sleep and awake states
Orexin
Drug classes for insomnia
Benzodiazepines (BNZ), BNZ receptor agonists (BRAs), Melatonin receptor agonists, tricyclic antidepressants, 1st gen anti-histamines
MOA of BNZ and BRAs
Binding to GABA-A receptor (but at different locations) - GABA channel open longer - more inhibitory action - more CNS depression; BRAs have ceiling effect at high doses
Goals of insomnia drug pharmacokinetics
Rapid onset time and sufficient durability as to not wake up in the middle of the night but not too long as to have “morning after” symptoms
Benzodiazepine drugs
Estazolam, flurazepam, quazepam, temazepam, triazolam
Pregnancy category for BNZ
Category X!
Side effects of BNZs
Contraindicated with COPD, driving, depression, other CNS drugs, and glaucoma
BNZ with least CYP interaction
Temazepam
BNZ receptor agonists
Zolpidem, zaleplon, eszopiclone
Zolpidem
Most widely prescribed hynotic, only drug approved for “middle of the night” awakening (short acting/less durable)
Role of melatonin on sleep
Works on suprachiasmatic nucleus and sleep-wake switch
Antidepressants for insomnia
Doxepin, mirtazapine, trazodone
Side effect of antidepressants
Suicidal ideations
First generation anti-histamines
Diphenhydramine and doxylamine; cross the BBB
Drug offenders of insomnia
TCA, MAOI, SSRIs, Venlafaxine, Bupriopion, Levodopa, Felbamate, Beta-Blockers, Decongestants, Antibiotics, Asthma meds, Stimulants
NSAIDS MOA for migraine Tx
Inhibiting inflammatory stimuli, thus decreasing MAPK and decreasing CGRP synthesis
Triptans MOA for migraine Tx
Selective carotid vasoconstriction and presynaptic inhibition of trigeminovascular inflammatory response
NSAIDS for migraine
Ketoprofen, fenoprofen, nabumetone, ibuprofen, naproxen
NSAIDS in pregnancy
Cat C; but avoid in late pregnancy bc of PDA and prolonged labor
NSAID combinations
Combined with butalbital (for sedative effects via GABA) and caffeine (for caffeine withdrawal headaches)
Serotonin agonists “triptans”
Almotriptan, Eletriptan, Frovatriptan, Naratriptan, Rizatriptan, Sumatriptan, Zolmitriptan
Triptans with fastest onset
Sumatriptan - given sub-Q
Triptans most durable (also long onset)
Naratriptan and frovatriptan
Contraindications of triptans
Don’t take with other vasoconstricting drugs or ergots; don’t combine with SSRIs or SNRIs (serotonin syndrome)
Ergots
Dihydroergotamine, ergotamine
Location of ergot receptors
CNS and periphery (unlike triptans)
Ergot use in pregnancy
NO!…Cat X
Migraine drug to use during pregnancy
Acetaminophen; opioids maybe in later trimesters
Tx of menstrual migraine
NSAIDS 2-3 days before period until it ends
Migraine and oral contraceptives
Multiplicative risk when taking OC and having migraine w/ aura
Antiemetics used in migraine
Metoclopramide, prochlorperazine, promethazine, chlorpromazine
MOA of antiemetics
All block D2 centrally except promethazine (cholinergic blockade)
Management of brain metastases
Antitumoral agents (chemo generally not indicated) and steroids (for brain edema) and anticonvulsants (for seizures). Definitive Tx with surgery or radiation
Mechanisms of resistance in brain tumors
Inability to pass BBB, overexpression of P-gp, and gene-related effects from astrocytes (don’t forget also the usual mechanisms from regular tumors too)
Uses for Temozolomide
Astrocytoma, GBM, malignant glioma, malignant melanoma
MOA of Temozolomide
Pro-drug yielding DNA methylator
Mechanism of resistance to TMZ
Repair with methyl guanine methyl transferase
Nitrosourea drugs
Carmustine (BCNU) and lomustine (CCNU)
MOA of nitrosoureas
Alkylating agents; CARmustine also CARbamylates proteins
Side effects of nitrosoureas
Myelosuppression, pulmonary toxicity, endocrine dysfunction
Inhaled Anesthetics
Gases: nitrous oxide, Liquids: halothane, enflurane, isoflurane, desflurane, sevoflurane
Conscious sedation
Maintain protective reflexes, airway maintained, response to external stimuli
Levels of sedation
Analgesia, anxiolysis, conscious sedation, deep sedation, general anesthesia
Advantage of inhalation and IV route
Immediate control over dose and duration of action
Minimum Alveolar Concentration
Minimum amount of drug required to render half of the patients unconscious
Correlation of MAC and lipid solubility
Higher partition coefficient (more lipid soluble) means lower MAC (more potent)
Agents containing halogens
Isoflurane, desflurane, sevoflurane (fluorine makes it less volatile)
Incomplete anesthetic
Nitrous oxide; MAC 105% - does not work completely, so don’t use alone!
Inhalation agents with faster equilibrium in blood
Sevoflurane and desflurane
Ventilation rate and arterial tension
More delivery to blood with greater ventilation; more pronounced for nitrous oxide
Respiratory effect of inhaled agents
Increased respiration rate and decreased tidal volume
CV effects of inhaled agents
Decreased blood pressure and cardiac output
Inhaled agent with no CV effects
Nitrous oxide
Inhaled agent with analgesic effects
Nitrous oxide
Inhaled agents with muscle relaxant properties
Enflurane and isoflurane
Inhaled agents causing hepatic toxicity and arrhythmias
Halothane
Inhaled agent that causes seizures
Enflurane
Toxicity of nitrous oxide
Teratogen, myelin sheath degeneration, B12 deficiency
Problems with nitrous oxide
Second gas effect, diffusional hypoxia, solubility
Targets of IV agents
Mostly reinforces GABA and glycine inhibitory effects; propofol and ketamine work on NMDA receptors for glutamate
MOA of propofol
Acts like GABA itself and also blocks binding of glutamate
MOA of ketamine
Physically blocks ion channel
Drug distribution of IV agents
Instant effect - goes to high flow organs first (brain, heart, liver, kidneys) then to skeletal muscle/skin and then accumulates in adipose tissue
Redistribution of IV agents
Drug passes BBB by going down concentration gradient into the brain and then leaves BBB when gradient inverts
IV agent with longest half life….shortest?
Longest - diazepam; shortest - etomidate
IV agent with increased cerebral blood flow
Ketamine
IV agent with increased ICP
Ketamine again
IV agent without respiratory depression
Ketamine a third time
IV agent with cardiostimulatory effect
Thiopental, propofol, but mainly ketamine
Best drug to use during surgery if there is nausea and vomiting as an adverse effect
Propofol (anti-emetic)
IV agent that inhibits steroidogensis
Etomidate