41 terms

Psychiatry drugs

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Nigrostriatal
Dopamine Extrapyramidal motor function
Mesocorticolimbic
Dopamine - Regulates emotional behavior and cognition
Arcuate-Pituitary
Inhibits prolactin secretion from anterior pituitary
Acute dystonia
Extrapyramidal effect of typical antipsychotics:
Spasmodic or sustained involuntary contractions of muscles in the face, neck, trunk, pelvis and extremities
Tx: Anti-cholinergic
Parkinsonism
Side effect of typical antipsychotics
Muscle stiffness, cogwheel rigidity, tremor, shuffling gait, stooped posture
Akathisia
Side effect of typical antipsychotics
Subjective feeling of inner restlessness and urge to move
Objective increase motor activity
Tx: benzos, beta antagonists, anti-cholinergics
Diphenhydramine
Antidote to dopamine-related side effects
tardive dyskinesia
Continuous writhing movements of tongue, mouth, fingers, hands and sometimes feet
Neuroleptic malignant syndrome
Life threatening, side effect
can occur ANY TIME
fever, sweating, tachycardia, HTN, increased WBC, liver enzymes
m>f, young>old
Chlorpromazine
TYPICAL antipsychotic, LOW potency
MoA:
Anticholinergic, H1 antagonist, alpha-antagonist
D2 antagonist --> depolarization blockade after several weeks. Dopamine neurons become depolarized, voltage-gated Na channels deactivated)
Dopaminergic transmission in nucleus accumbens

Clinical: Schizophrenia (+ Sx), mania
Other psychotic disorders
Perphenazine
TYPICAL antipsychotic, MID potency
MoA:
D2 antagonist --> depolarization blockade after several weeks. Dopamine neurons become depolarized, voltage-gated Na channels deactivated)
Dopaminergic transmission in nucleus accumbens


Clinical: Schizophrenia (+ Sx), mania
Other psychotic disorders
Haloperidol
TYPICAL antipsychotic, HIGH potency
MoA:
D2 antagonist --> depolarization blockade after several weeks. Dopamine neurons become depolarized, voltage-gated Na channels deactivated)
Dopaminergic transmission in nucleus accumbens


Clinical: Schizophrenia (+ Sx), mania
Other psychotic disorders
Benztropine
MoA: Anticholinergic and anti-histamine effects (atropine and diphenhydramine)

Treatment for side effects of conventional antipsychotics
Treats extrapyramidal side effects of conventional antipsychotics (except tardive dyskinesia)
Clozapine
MoA: Less D2 blocking, Binds D4 muscarinic, H1, and alpha-1 receptors
Tightly binds 5HT-2 A and C receptors & alpha-2 receptors

Clinical: Tx-resistant schizophrenia, good for +, - and cognitive symptoms
Off label: bipolar, OCD, psychosis
MOST EFFECTIVE antipsychotic

Selectives
Olanzapine
Atypical antipsychotic
Low affinity for D2 receptors
High affinity for 5HT-2, muscarinic, H1 and alpha-1 receptors

Schizophrenia, bipolar. Off label: psychosis

Has sedating effect
Hepatic metabolism
Risperidone
MoA: Relatively high D2 binding
High 5HT-2 and alpha2 binding, moderate H1 binding

MoA: schizophrenia, bipolar, autism
Off label: Tourette's PTSD, psychosis
Clozapine side effect
Metabolic syndrome (increase BMI, decrease HDL, increase BP, DM, cardiac risks)
Clozapine side effect
Granulocytosis
Quetiapine
Atypical antipsychotic
MoA: Main effects due to D2 and 5HT2 antagonism

Side effects due to H1 antagonism (sedation) and alpha-1 antagonism (OH)

LESS weight gain than other atypicals
Aripiprazole
Atypical antipsychotic
MoA: PARTIAL agonist at D2 and 5HT-1A receptors (prevents extrapyramidal side effects)
Blocks 5HT-2A receptors

Clinical:
Schizophrenia, Bipolar, MDD,
Off label: Tourette's psychosis, conduct disorder aggression in children
Amitriptyline
Tricyclic anti-depressant
MoA: Blocks presynaptic reuptake of NE, also weakly effects 5HT reuptake

Clinical: Depression

Side effect profile: Muscarinic M1, H1 (drowsiness), alpha-1 effects, SSRI effects, Cardiac effects
Drug interactions: MAOIs
Nortriptyline
Tricyclic antidepressant
MoA: Increase postsynaptic 5HT-1, decrease beta-adrenergic receptors and presynaptic alpha-2 receptors
STRONG H1 antagonism
Clinical: Depression, off label: neuropathic pain, ADHD, anxiety

Side effect profile: Muscarinic M1, H1 (drowsiness), alpha-1 effects, SSRI effects, Cardiac effects
Drug interactions: MAOIs
Tricyclic side effects
Receptor blockade:
Muscarinic M1 receptors - dry mouth, urinary retention, constipation, tachycardia, memory impairment, drowsiness, delirium
Histamine H1 receptors - drowsiness, weight gain
Alpha-1 effects: dizziness, OH

Drug interactions: MAOIs, barbiturates
Fluoxetine
SSRI
MoA: Inhibits 5HT reuptake: downregulates presynaptic 5HT-1A,B/D and alpha-2 receptors and serotonin transporter, Desensitizes post-synapatic 5HT receptor

Clearance: ACTIVE metabolites, LONGEST t.5, least withdrawal, activating properties
ENHANCES TCAs by inhibiting CYP2D6

Clinical: MDD, bulimia, OCD, premenstrua dysphoric disorder, panic disorder, BPD. Off label: PTSD
Sertraline
SSRI
MoA: Inhibits 5HT reuptake: downregulates presynaptic 5HT-1A,B/D and alpha-2 receptors and serotonin transporter, Desensitizes post-synapatic 5HT receptor
MILD DA REUPTAKE INHIBITION, few drug interactions

Clinical: OCD, MDD, panic disorder, PMDD, social anxiety
Paroxetine
SSRI
MoA: Inhibits 5HT reuptake
Blocks NE reuptake, anticholinergic blockade, sedating properties. WITHDRAWAL
NOT SAFE in pregnancy
Enhances TCA by inhibiting CYP2D6

Side effects: dysphoria, irritability, agitation
DISCONTINUATION SYNDROME

Clinical:
OCD, MDD, panic disorder, PMDD, social anxiety, GAD, PTSD, PMDD
Citalopram
SSRI
MoA: Inhibits 5HT reuptake
FEWEST drug interactions

Clinical:
MDD, OCD in children, smoking cessation/alcohol abuse
Venlafaxine
SNRI
Low dose -> SSRI effect, high dose -> SNRI effect
High bioavailability

Clinical: MDD< GAD, social anxiety, panic

Side effects: Increase HR and BP, headache, nausea, sex dsyfxn, dizziness, sedation, insomnia
Duloxetine
SNRI
Blocks 5H and NE reuptake

Clinical: MDD, GAD, diabetic neuropathy, fibromyalgia

Side effects; Monitor BP pre/during tx
MAO-A
Breaks down NE, 5HT, tyramine
MAO-B
Breaks down dopamine
Trazodone
SNRI
Blocks 5HT-2a, 5HT, and NE reuptake

Clinical: Depression, insomnia (off-label)

Side effects; MYOCARDIAL excitability, OH, priapism
Mirtazapine
MoA: Blocks alpha-2 receptors that inhibit 5HT, NE release!
Blocks H1 receptors

Clinical: depression

Side effects: H1 effects: sedation, weight gain
Bupropion
NDRI (NE and DA reuptake inhibitor)

MDD, season affective disorder, smoking sessation

ENERGIZING EFFECT
Phenelzine
MAOI

Irreversibly prevents oxidation of amines by MAO in presynaptic terminals, increasing amount available for release into synaptic cleft

Side effects: OH, drug interactions: SSRIs, tyramine, headache, HTN crisis
Serotonin syndrome
Cognitive effects: headache, agitation, hypomania, mental confusion, hallucinations, coma

Autonomic effects: shivering, sweating, hyperthermia, HTN, tachycardia, nausea, diarrhea.

Somatic effects: myoclonus, hyperreflexia, tremor.
Selegiline
MAO-B inhibitor (inhibits dopamine reuptake)

MDD, Parkinsons
Lithium
Mood stabilizers
MoA: Inhibits IMPase and IPPase, causes exhaustion of inositol signaling pathway
GSK-3beta inhibition

Clinical: Bipolar disorder

Side effects: blocks AC, inhibits vasopressin
Volume depletion (nephrogenic diabetes insipidus), subclinical hypothyroidism
GI: diarrhea, vomiting, nausea
CV: flat T waves, sinus node depression
Valproic acid
Downregulates PKC and MARCKs, inhibits GSK-3beta

Clinical: seizures, BPD, migraine prophylaxis, epilepsy

Side: Less toxic than lithium, nausea, tremor, weight gain, thrombocytopenia, liver damage, teratogenic
Carbamazepine
Mood stabilizer
Seizures, bipolar

Stabilizes inactivated Na+ channels?

Side: Neutropenia, liver damage, teratogenic. OVERDOSE: delirium, coma, ventricular arrhythmias
Lamotrigine
Mood stabilizer
Bipolar disorder

Inhibits glutamate release, inhibits voltage-gated sodium channels

More effective than lithium for BPD DEPRESSION
Headache, nausea, insomnia