PSYCHOPHARMACOLOGY
MA. PRISCILLE OGENA, TOLOD, MD, FPNA
Adult Neurology
Stroke and Vascular Neurology
ANTIDEPRESSANTS
• MDD • Classes
• GAD • SSRIs
• SNRIs
• OCD • TCAs
• PTSD • MAOIs
• Chronic pain • Atypical antidepressants
Selective Serotonin Reuptake
Inhibitors (SSRIs)
Mechanism of Action
• selectively inhibits the reuptake
of serotonin in the synaptic
cleftà increased concentration
of serotonin available for
signaling between neurons
Common SSRIs Pharmacokinetics
• Fluoxetine (Prozac) • Administration: oral
• Sertraline (Zoloft) • Metabolism: liver, cytochrome P450
• Paroxetine (Paxil) enzyme system
• Citalopram (Celexa) • Half-life: longer- fluoxetine, shorter-
sertraline
• Escitalopram (Lexapro)
• Fluvoxamine (Luvox)
Side Effects
• Nausea
• Diarrhea or constipation
• Headache
• Insomnia or drowsiness
• Sexual dysfunction (e.g., decreased libido, delayed ejaculation, or
erectile dysfunction)
• Weight gain or weight loss
Adverse Reactions
• Serotonin syndrome
• potentially life-threatening
• agitation, confusion, rapid heart
rate, elevated blood pressure, and
hyperthermia
• Increased risk of suicidal
thoughts or behaviors
• Withdrawal symptoms upon
abrupt discontinuation
Interactions Precautions
• other antidepressants • pregnancy and breastfeeding
• migraine medications (e.g.,
triptans)
• certain pain relievers (e.g.,
tramadol)
• herbal supplements (e.g., St.
John's Wort)
Serotonin and Norepinephrine
Reuptake Inhibitors (SNRIs)
Mechanism of Action
• blocks the reuptake of serotonin
and norepinephrine in the
synaptic cleftà increased
concentration of serotonin and
norepinephrine available for
signaling between neurons
Common SNRIs Pharmacokinetics
• Venlafaxine (Effexor) • Administration: oral
• Duloxetine (Cymbalta) • Metabolism: liver, cytochrome
• Desvenlafaxine (Pristiq) P450 enzyme system
• Levomilnacipran (Fetzima) • Half-life: longer- duloxetine,
shorter- venlafaxine
• Milnacipran
• Atomoxetine
Side Effects
• Nausea
• Headache
• Dry mouth
• Insomnia or drowsiness
• Constipation
• Dizziness
• Sweating
• Increased heart rate or blood pressure
Adverse Reactions
• Serotonin syndrome
• Increased risk of suicidal thoughts or behaviors
• Withdrawal symptoms upon abrupt discontinuation
Interactions Precautions
• other antidepressants • pregnancy and breastfeeding
• migraine medications (e.g.,
triptans)
• certain pain relievers (e.g.,
tramadol)
• herbal supplements
Tricyclic Antidepressants (TCAs)
Mechanism of Action
• blocks the reuptake of both
serotonin and norepinephrine
• additional effects on other
neurotransmitter systems
(histamine and acetylcholine)
Common TCAs Pharmacokinetics
• Amitriptyline • Administration: oral
• Nortriptyline • Metabolism: liver, cytochrome
• Imipramine P450 enzyme system
• Desipramine • Half-life: longer- amitriptyline,
shorter- nortriptyline
• Clomipramine
• Doxepin
Side Effects
• Sedation or drowsiness
• Dry mouth
• Blurred vision
• Constipation
• Urinary retention
• Weight gain
• Sexual dysfunction
• Orthostatic hypotension
• Cardiac arrhythmias
Adverse Reactions
• Cardiac toxicity
• Increased risk of suicidal thoughts or behaviors
• Withdrawal symptoms
• Overdose potential
Interactions Precautions
• other antidepressants • older adults
• migraine medications (e.g., • individuals with narrow-angle
triptans) glaucoma, urinary retention, or
• certain pain relievers (e.g., cognitive impairment
tramadol)
• herbal supplements
Monoamine Oxidase Inhibitors
(MAOIs)
Mechanism of Action
• irreversibly inhibiting the activity
of monoamine oxidase
• MAO-A- metabolizes serotonin
and norepinephrine
• MAO-B- metabolizes dopamine
Common MAOIs Pharmacokinetics
• Phenelzine (Nardil) • Administration: oral
• Tranylcypromine (Parnate) • Metabolism: liver
• Isocarboxazid (Marplan) • Half-life: generally have a longer
• Selegiline (Emsam) - transdermal duration of action vs other
patch antidepressants
Side Effects • "cheese effect" or hypertensive
crisis
• Avoid foods high in tyramine
• Orthostatic hypotension
• aged cheeses, cured meats, and
• Dizziness certain alcoholic beverages
• Drowsiness
• Insomnia
• Dry mouth
• Constipation
• Weight gain
• Sexual dysfunction
Adverse Reactions
• Hypertensive crisis
• Serotonin syndrome
• Increased risk of suicidal thoughts or behaviors
• Withdrawal symptoms
Interactions Precautions
• other antidepressants • individuals with cardiovascular
• sympathomimetic agents disease, hypertension, or history
of migraine headaches
• over-the-counter cold and allergy
medications • pregnancy and breastfeeding
Atypical Antidepressants
Atypical Antidepressants
• Bupropion
• Mirtazapine
• Trazodone
• Vortioxetine
• Vilazodone
Bupropion (Wellbutrin)
• norepinephrine-dopamine
reuptake inhibitor (NDRI)
• useful option for individuals who
experience sexual dysfunction or
weight gain with other
medications
• FDA-approved for smoking
cessation
Mirtazapine (Remeron)
• noradrenergic and specific
serotonergic antidepressant (NaSSA)
• enhances the release of norepinephrine
and serotonin
• also acts as an antagonist at certain
serotonin receptors (5-HT2 and 5-HT3
receptors) and histamine receptors
(H1 receptors)
• sedative effects
• less sexual dysfunction vs SSRIs and
SNRIs
Trazodone (Desyrel)
• antagonist at serotonin receptors
(5-HT2A and 5-HT2C receptors)
• weak serotonin reuptake
inhibitor
• sedative effects
• less sexual dysfunction vs SSRIs
and SNRIs
• orthostatic hypotension and
sedation at higher doses
Vortioxetine (Trintellix)
• multimodal antidepressant
• serotonin reuptake inhibitor
• serotonin receptor agonist
• antagonist at certain serotonin
receptors (5-HT1A, 5-HT1B, 5-HT3,
and 5-HT7 receptors)
• more favorable side effect profile
• FDA-approved for GAD
Vilazodone (Viibryd)
• serotonin reuptake inhibitor and partial agonist at serotonin receptors
(5-HT1A receptors)
• less sexual dysfunction
• faster onset of action vs some other antidepressants
• FDA-approved for MDD
SEDATIVE-HYPNOTICS
Categories
• benzodiazepines
• non-benzodiazepine hypnotics
• barbiturates
Benzodiazepines
Mechanism of Action
• enhance the effect of GABA by
binding to the GABA-A receptor
complexà
• increased frequency of
chloride channel openingà
• membrane hyperpolarization
and inhibition of neuronal
excitability
Pharmacokinetics Examples
• Oral absorption • Diazepam
• Hepatic metabolism, • Lorazepam
cytochrome P450 • Alprazolam
• Clonazepam
Non-benzodiazepine Hypnotics (Z-drugs)
Mechanism of Action
• bind selectively to the
benzodiazepine subtype of the
GABA-A receptor complexà
• enhance the inhibitory effect
of GABA
Pharmacokinetics Examples
• Oral absorption • Zolpidem
• Hepatic metabolism • Zaleplon
• Shorter half-lives vs BZDs • Eszopiclone
Barbiturates
Mechanism of Action
• enhance the effect of GABA by
increasing the duration of
chloride channel opening
Pharmacokinetics Examples
• oral absorption • Phenobarbital
• metabolized by hepatic • Pentobarbital
microsomal enzymes • Secobarbital
• narrow therapeutic index
• high potential for dependence
and overdose
Pharmacological Effects
• Sedation- calming effect
• Hypnosis- induce and maintain sleep
• Anxiolysis- reduce feelings of anxiety or tension
• Muscle Relaxation
• Anticonvulsant
Adverse Effects
• Respiratory Depression- suppress respiratory drive
• Tolerance and Dependence- prolonged use
• Cognitive Impairment- particularly in elderly
• Risk of Abuse
• Paradoxical Reactions (agitation, aggression, or disinhibition)
Thank you!J
