Pharmacology - Block 2 - Part 4

godknows3's version from 2016-03-07 03:58

General Anesthetics

Question Answer
Inhaled GA, barbiturates, BZDs mechanism of action isGABAa Receptor Agonist
Ketamine mechanism of action isNMDA Receptor Antagonist
The solubility of the anesthetic. Its concentration in inspired air. Pulmonary ventilation rate. Pulmonary blood flow. Arteriovenous concentration gradient are the factors that determine this characteristic of an anestheticSpeed of Induction of Anaesthesia
The ratio of the concentration in blood to the concentration in the gas phaseBlood:Gas Partition Coefficient
The higher a drug's Blood:Gas Partition Coefficient the higher this is in bloodSolubility
The higher a drug's Blood:Gas Partition Coefficient, the lower this isTime of Induction
The measure of potency of Inhaled AnestheticsMinimum Alveolar Concentration (MAC)
The less the MAC is for a drug, the greater this is of a drugPotency
This is the least potent of the inhalation anestheticsNitrous oxide
This is the most potent of the inhalation anestheticsHalothane
This inhalation anesthetic sensitizes the myocardium to catecholamines which may induce arrhythmiasHalothane
This inhalation anesthetic may cause bronchospasm and is contraindicated in patients with asthmaDesflurane
A genetic mutation in ryanodine receptors in the skeletal muscle. Exposure to inhalation anesthetic (especially when halogenated GA used with succinylcholine) will cause muscle rigidity and rise in body temperatureMalignant Hyperthermia
Malignant hyperthermia is treated with immediate administration of this drugDantrolene
Undergoes >40% hepatic metabolism. Rare cases of postoperative hepatitis occur. Can sensitize the heart to CAs (arrhythmias)Halothane
Megaloblastic anemia may occur after prolonged exposure due to decreases in methionine synthase activityNitrous Oxide
Barbiturates (Thiopental & Methohexital), Benzodiazepines (diazepam,Midazolam), Opioids (Morphine & Fentanyl), Propofol, Etomidate, and Ketamine are IV anesthetics that can be used to do thisAnesthesia Induction
Thiopental, Propofol and Etomidate are the IV anesthetics that are most commonly used to do thisAnesthesia Induction
This drug is no long used for anesthesia induction in the USThiopental
Produces anesthesia as rapidly as i.v. barbiturates but recovery is more rapid. Has Antiemetic effects. Commonly used as an anesthetic in outpatient surgical procedures. Can cause marked hypotension (decreased PVR)Propofol
Rapid induction. Short duration of action. Advantage - Little effect on CV & Respiration. Primarily used in pts with limited cardiac or respiratory reserve. A/E: Pain and myoclonus on injection. Prolonged administration can cause adrenal suppressionEtomidate
State of analgesia and amnesia produced when fentanyl is used with droperidol and nitrous oxideNeurolept Anesthesia
High doses used for Neurolept anesthesia can cause chest wall rigidity & post-op respiratory depression which can be reversed by administration ofNaloxone
A “dissociative anesthetic” that produces a cataleptic state that includes intense analgesia, amnesia, eyes open, unresponsive to commands or pain. Acts as an antagonist to glutamic acid (blocks the actions of glutamate on NMDA receptor). Cardiac stimulant- Increases heart rate & blood pressure Ketamine
Ketamine is a derivative of this drugPhencyclidine (PCP)

Local Anesthetics

Question Answer
Applied locally. Reversibly block nerve conduction. Cause loss of sensation without unconsciousnessLocal Anesthesia
Cocaine, Procaine, Tetracaine, Benzocaine are examples of this type of local anestheticEster-linked Anesthetic
Lidocaine, Bupivacaine, Mepivacaine, Etidocaine, Prilocaine are examples of this type of local anestheticAmide-linked Anesthetic
LA act in their cationic(ionic) form but most reach their site of action by penetrating the nerve sheath and axonal membrane asunionized form
All local anesthetics have this range of pKaBasic
Reduces systemic absorption due to local vasoconstriction when coadminstered with a LA and prolong duration of local anesthesiaEpinephrine
Metabolized by hydrolyzed by pseudocholinesterasesEster-linked Anesthetic
Metabolized by hepatic CYP enzymesAmide-linked Anesthetic
Local anesthetics effect depends on fiber diameter and myelinationDifferential Blockade
These neurons will be the first fibers block by a local anestheticType B and C Fibers
Circumoral, tongue numbness, metallic taste, nystamgmus, muscle twitchings, Seizures, depression and loss of consciousnessLA Toxicity
Treatment for seizures induced by LADiazepam
The most cardiotoxic LA is this drugBupivacaine
Accumulation of O-toluidine can cause methaemoglobinemia and is treated by acorbic acidPrilocaine
Metabolised to Paraaminobenzoic acid which can cause allergic reactionsEster LA

Skeletal Muscle Relaxants

Question Answer
Relaxant that works at the neuromuscular jucuntionNeuromucscluar blockser
Relaxant that works by depressing the CNS and therebySpasmolytics
D-tubocurarine, Vecuronium, Pancuronium, Doxacurium, Rocuronium are examples of these neuromuscular blockersCompetitive Blockers
Succinylcholine is an example of this neuromuscular blockersDepolarizing Blockers
Diazepam, Baclofen, Tizanidine, Dantrolene, Gabapentin are examples of these types of muscle relaxantsSpasmolytics
Competitive antagonists of the N[m] receptorNon-Depolarizing N[m] Blockers
Non-Depolarizing N[m] Blockers and Depolarizing N[m] blockers can be overcome and treatment for overdose is this drugNeostigmine
Agonists at N[m] receptor that opens ion channels causing depolarization initially. Maintains stimulation which results in the inability of repolarization causing muscle relaxationSuccinylcholine
Phase in which succinylcholine action is augmented by administration of neostigminePhase I
Phase in which succinylcholine action is reversed by administration of neostigminePhase II
Rapid onset - 1 minute; Short duration of action: 3-5 minutes; rapidly hydrolyzed by plasma pseudocholinesterase; in people with congetnital deficiency of plasma cholinesterase experience long lasting block leading to apneaSuccinylcholine
Test used to measure the response a person has to succinylcholineDibucaine Number
The normal Dibucaine number is80
This drug will cause histamine release causing hypotension and bronchospasmD-Tubocurarine
This drug can cause hyperkalemia, increased intraocular pressure, myalgias, apnea and malignant hyperthermiaSuccinylcholine
Drug that decreases the muscle tone without causing paralysisSpasmolytics
The mechanism of action is centrally acting that depress the sinal and suraspinal reflexes in spinal cord which decreases muscle toneSpasmolytics
Diazepam, Tizanidine and Baclofen action is at this site of the nervous systemCNS
A genetic condition which a person responses to inhaled anesthetics and succinylcholine by persistent release of Ca+2 from the S.R. leads to muscle rigidity and a rise in body temperatureMalignant Hyperthermia

Opioid Analgesics

Question Answer
Natural, synthetic and semisynthetic drugs with morphine- like actionsOpioids
Morphine, Methadone, Meperidine, Fentanyl, Oxymorphone and Hydromorphone are opioids in this classStrong Agonist
Codiene, Hydrocodone and Oxycodone are opioids in this classMild to Moderate Agonist
Buprenorphine, Nalbuphine and Pentazocine are opioids in this classMixed Agonist- Antagonist
Naloxone and Naltrexone are opionids in this classAntagonist
Inhibition of adenylate cyclase leading to a decrease in cAMP, decreasing kinase activity which inhibit the release of NT ACh, NE, 5-HT, glutamate, and substance P. In addition, decreases neuronal calcium entryOpioid Pre-synaptic Mechanism
increase K+ currents leading to hyperpolarization and decreasing the firingOpioid Post-synaptic Mechanism
Analgesia- increased pain tolerance, decreased perception and reaction to pain. Euphoria and Sedation. Respiratory depression which increases Pco2 leads to cerebral vasodilation. Suppression of the cough. Miosis. Nausea vomiting. Trunkal rigidityOpioid CNS Effect
Opioids are contraindicated in thisHead Injury
GIT - Constipation due to ↑ muscle tone and ↓ intestinal peristalsis. CVS: most opioids no direct effect on heart except Meperidine- tachycardia because of its antimuscarinic action. Biliary tract: ↑ biliary sphincter tone and pressure (> 10X), which may cause biliary colic (except meperidine)Opioid Peripheral Effects
Tolerance develops to most of opioids effects, with the exception of theseMiosis and Constipation
Adverse effects include Respiratory depression, Nausea, Vomiting, Constipation and MiosisOpioids
Contraindications include use of full and partial agonists which induce withdrawal. Patients with head trauma due to a possible increase in intracranial pressure. Pregnancy - when used in pregnancy withdrawl symptoms in fetus. Patients with impaired pulmonary, renal or hepatic functionOpioids
Drug interactions involving opioid analgesics with Ethanol, Sedative-hypnotics, Anesthetics, Antipsychotic drugs, Tricyclic antidepressants, and AntihistaminesAdditive CNS Depression
Concomitant use of certain opioids (e.g., Meperidine) with MAO inhibitors increases the incidence of thisSerotonin Syndrome
Opioid that has antimuscarinic action on the heart and does not increase biliary tract toneMeperidine
DOC for biliary colicMeperidine
DOC for the relief of pain due to myocardial infarction. High dose iv often the major component of anesthesia for cardiac surgery. Used for treatment of dyspnea due to left ventricular failureMorphine
Antitussive drugs includeCodeine and Dextromethorphan
Selective antidiarrheal opioids includeDiphenoxylate and Loperamide
Management of opioid withdrawal states and in maintenance programs for addictsMethadone and Buprenorphine
The following symptoms of chills, lacrimation, rinorrhea, gooseflesh, mydriasis, hyperventilation, diarrhea, anxiety and hostility are indications of thisOpioid Withdrawl
Synthetic narcotic; actions similar to morphine except pupils may dilate and no anti-tussive effect. Strong k agonist. Toxic metabolite may → CNS excitation, seizures, convulsions and tremors if accumulates. Has Antimuscarinic effect - Used in biliary colic. Can cause tachycardia. Inhibits Serotonin reuptakeMeperidine
Is partial agonist at opioid receptor. It is converted to active form morphine by enzyme CYP2D6. Failure to respond to codiene ..can be due to Genetic variability in CYP2D6Codeine
Synthetic opioid that is more potent than morphine. Rapid onset and short duration. Used for balanced anesthesia when used with droperidol for neurolept analgesia. Transdermal patch & lollipop that dissolves slowly for transmucosal absorption. Patches are primarily used for chronic malignant pain, with a duration of action of 72 hrsFentanyl
Duration of action for analgesia is longer than morphine (t1/2 15-55 hrs). Used to treat heroin withdrawal and pain of terminal cancer. Causes less sedation, euphoria, and emesis than morphine. Withdrawal is milder, slower in onset, and more prolonged than with heroin or morphineMethadone
Legally banned in U.S. 2-5x as potent as morphine as analgesic. More lipid soluble and crosses BBB faster than morphine. Causes extreme euphoria when administered IVHeroin (Diacetylmorphine)
Antagonist that is used for long term withdrawl treatment. Also approved for alcohol deaddiction (it decreases craving for alcohol)Naltrexone
Antagonist used for emergency treatment of opioid overdoseNaloxone
Pure opioid receptor antagonistNalmefene

Parkinson's Disease

Question Answer
A degenerative disorder of the CNS that often impairs the sufferer's motor skills and speech. Symptoms include Tremor at rest, Rigidity, Bradykinesia / akinesia: respectively, slowness or absence of movement, Postural instability, Gait abnormalities, fatigue and Soft speech/droolingParkinson's Disease