Intro to Neuropsychopharmacology Part 2 Flashcards
Antimanic Drugs
Lithium
Valproic Acid
Divalproex
Carbamazepine
Antianxiety agents, Hypnotics, and Muscle Relaxants
- Alprazolam
- Buspirone
- Chloral Hydrate
- Diazepam
- Flumanzenil
- Flurazepam
- Lorazepam
- Pentobarbital
- Zolpidem
Muscle Relaxants
- Baclofen
- Tizanidine
- (Diazepam)
Lithium Mechanism of Action
Inhibits the recycling of inositol - Impacts IP3 and DAG second messenger system
Lithium Pharmacokinetics
Readily Absorbed after oral administration
Eliminated in urine approximately 95%
Sodium levels effect lithium excretion and retention
Narrow therapeutic window (.6 - 1.2 m Eq/l)
Interactions with ACE inhibitors and angiotensin II receptor blockers
Toxic Reactions and side Effects to Lithium
- Fatigue
- Tremor
- GI symptoms
- Goiter
- Slurred Speech and Ataxia
Lithium should be used with caution in ______ _______
Pregnant women
Serious toxicity to Lithium
Plasma levels about 2mEq/L
- Impaired consiousness
- Rigidity and hyperactive deep reflexes
- Coma
Therapeutic uses of lithium
Manic episodes and to prevent recurrences of bipolar depression and mania
Alternatives to Lithium and their mechanism of action
Carbamazepine, divaloproex (Valproic acid)
- Alters ion conductances. Use dependent effect on Na+ channels
- Inhibits the generation of repetitive action potentials
Carbamazepine
Mechanism of Action:
Pharmacokinetics:
Mechanism of Action: Blocks sodium channels at therapeutic concentration.
Pharmacokinetics: Unpredictable absorption; hepatic enzyme induction; toxicity is dose-related
Carbamazepine Toxicity
- Diplopia and ataxia
- G.I. upset
- Drowsiness
- Rare Blood dyscrasias
- Teratogen - increased incidence of spinal bifida
Valproic Acid and Divalproex
Mechanism of Action:
Pharmacokinetics:
- Mechanism of Action
- Blocks repetitive neuronal firing
- May reduce T-type Ca++ currents
- Increases GABA concentration
- Pharmacokinetics
- Well absorbed orally
- Bound to plasma protein
- Distributes in extracellular fluid
- Inhibits metabolism of Phenyoin and Carbamazepine
Side Effects and Toxicity of Valproic Acid
- GI upset
- Weight gain, hair loss
- Idiosyncratic hepatotoxicity
- Teratogenicity - Spina Bifida
What is Anxiety?
Anxiety symptoms are among the most common that are presented to family doctors and specialists. It has been estimated that from 4 - 8% of the general population has at some time had an anxiety disorder
Sleep and Insomnia
Sleep is a normal and reversible physiological state. Insomnia is a term for disorders of initiating and maintaing sleep
Neurochemistry of Sleep
- Slow wave sleep - Serotonin
- REM sleep - Norepinephrine
Benzodiazepines and barbituates: Mechanism of Action
Act at sites on the GABA receptor-chloride ion channel complex
GABA localization - Substantia Niagra, Globus Pallidus, Hippocampus
Limbic Structures - Amygdala, Hypothalamus, Spinal Cord
On the GABA receptor, GABA binding increases ________ conductance
chloride
Benzodiazapine Receptor
Found on GABA receptor-chloride channel complex
- Enhances action of GABA
- Increases frequency of GABA induced chloride channel openings
- Separate from barbiturate site
- There are also pure antagonists (Flumazenil) and inverse agonist compoundst active at receptor
Buspirone
- Partial agonist at 5-HT1A receptors - opens K+ channel
- Also binds to dopamine-D2 receptors
Alprazolam
CNS Effects:
Mechanism:
Uses:
Duration:
CNS Effects: Forebrain depression; Dependence
Mechanism: GABA enhancement
Uses: Anxiolytic, antipanic
Duration: Short
Diazepam
CNS Effects:
Mechanism:
Uses:
Duration:
CNS Effects: Broad CNS Depression; Dependence
Mechanism: GABA enhancement
Uses: Anxiolytic, sedative, muscle relaxant
Duration: Long
Buspirone
CNS Effects:
Mechanism:
Uses:
Duration:
CNS Effects: Little Sedation; No dependence
Mechanism: 5-HT effect
Uses: Amxiolytic
Duration: Delayed Onset
What drugs are used as hypnotics
Flurazepam (primarily)
Lorazepam