Central Nervous System Pharmacology Study Guide Sedative Hypnotics Barbiturates Prototypes Thiopental Phenobarbital Mechanism of Action Enhance GABA A receptor activity by increasing the duration of chloride channel opening Uses Anesthesia Thiopental Seizure control Phenobarbital Drug Interactions Induce hepatic enzymes leading to increased metabolism of other Side Effects Respiratory depression CNS depression dependence tolerance drugs Benzodiazepines Prototypes Midazolam Alprazolam Lorazepam Chlordiazepoxide Mechanism of Action Enhance GABA A receptor activity by increasing the frequency of chloride channel opening Uses Anxiety Insomnia Seizure control Alcohol withdrawal Side Effects CNS depression dependence respiratory depression at high doses Drug Interactions Potentiate effects of other CNS depressants alcohol opioids Ethanol Mechanism of Action Enhances GABA A receptor activity also acts on other neurotransmitter systems Uses Anxiolytic Sedative Antiseptic topical use Drug Interactions Potentiates effects of other CNS depressants Side Effects CNS depression dependence liver damage gastrointestinal bleeding Reversal Agents Flumazenil Hypnotics Z Drugs Zolpidem subunits Uses Insomnia Melatonin Agonists Ramelteon Mechanism of Action Competitive antagonist at GABA A receptors Uses Reversal of benzodiazepine effects in overdose or during anesthesia Mechanism of Action Binds selectively to GABA A receptors containing alpha 1 Side Effects Daytime drowsiness amnesia sleep related behaviors Mechanism of Action Agonist at melatonin receptors in the suprachiasmatic nucleus Uses Insomnia Side Effects Headache somnolence Orexin Antagonists Suvorexant Mechanism of Action Orexin receptor antagonist Uses Insomnia Side Effects Somnolence abnormal dreams Sedatives Buspirone Mechanism of Action Partial agonist at serotonin receptors Uses Generalized anxiety disorder Side Effects Dizziness headache General Anesthetics Volatile Inhaled Agents Halothane Sevoflurane Desflurane Mechanism of Action Enhance GABA A receptor activity NMDA receptor antagonism Uses General anesthesia Side Effects Respiratory depression arrhythmias malignant hyperthermia Halothane Gaseous Inhaled Agents Nitrous Oxide Mechanism of Action NMDA receptor antagonism Uses Analgesia adjunct to anesthesia Side Effects Limited dose dependent CNS effects Parenteral Agents Thiopental Midazolam Ketamine Propofol Etomidate Mechanism of Action GABA A receptor modulation Thiopental Midazolam Propofol Etomidate NMDA receptor antagonism Ketamine Uses Induction and maintenance of anesthesia Side Effects Respiratory depression cardiovascular depression emergence reactions Ketamine Local Anesthetics Amides Lidocaine Esters Procaine Anticonvulsants Sodium Channels Mechanism of Action Blocks voltage gated sodium channels Uses Local anesthesia antiarrhythmic systemic Side Effects Local irritation systemic toxicity CNS and cardiovascular Mechanism of Action Blocks voltage gated sodium channels Uses Local anesthesia Side Effects Allergic reactions methemoglobinemia Phenytoin Carbamazepine Lamotrigine Mechanism of Action Block voltage gated sodium channels Uses Seizure control Side Effects Nystagmus ataxia diplopia Stevens Johnson syndrome Carbamazepine Calcium Channels Ethosuximide Mechanism of Action Blocks T type calcium channels Uses Absence seizures Side Effects Gastrointestinal upset hirsutism GABA Benzodiazepines Midazolam Clobazam Mechanism of Action Enhance GABA A receptor activity Uses Seizure control Barbiturates Side Effects CNS depression dependence Phenobarbital Mechanism of Action Enhance GABA A receptor activity Uses Seizure control Mixed Other Side Effects CNS depression dependence Valproate Levetiracetam Gabapentin Cannabidiol Mechanism of Action Various GABA modulation calcium channel blockade etc Uses Broad spectrum anticonvulsant Side Effects Variable including gastrointestinal upset sedation weight gain Valproate behavioral changes Levetiracetam somnolence Gabapentin and potential drug interactions Cannabidiol