Antidepressants Flashcards
What are the symptoms of depression?
Sadness.
Despair.
Lack of pleasure.
Sleep and appetite changes.
Loss of energy.
Suicidal thoughts.
What are the two types of depression?
Unipolar: Major depressive disorder.
Bipolar: Bipolar disorder.
What are the symptoms of bipolar disorder (mania)?
Alteration between depression and euphoria.
Enthusiasm.
Rapid thought and speech.
Self-confidence.
Impaired judgement.
What are the monoamines?
Dopamine.
Norepinephrine.
Serotonin.
What is the monoamine hypothesis?
Depression is caused by a defect in the activity of monoamines, and the overexpression of monoamine receptors.
What is the strategy of treatment for depression?
Antidepressants are administered to enhance the actions of norepinephrine and/or serotonin in the brain.
What is the mechanism of action of selective serotonin reuptake inhibitors (SSRIs)?
They selectively inhibit serotonin reuptake, leading to an increased concentration of serotonin in the synaptic cleft.
What does the “selective” in “selective serotonin reuptake inhibitors” (SSRIs) mean?
They are selective as their selectivity for the serotonin transporter is 300 to 3000 times greater compared to the norepinephrine transporter.
What are the most common SSRI drugs?
Fluoxetine.
Citalopram.
Escitalopram.
Fluvoxamine.
Paroxetine.
Sertraline.
Why are SSRIs preferred as a first-line treatment for depression?
Because they target serotonin reuptake without significantly affecting muscarinic, α-adrenergic, and histamine H1 receptors.
(SSRIs) and (SNRIs) target serotonin reuptake without significantly affecting muscarinic, α-adrenergic, and histamine H1 receptors.
What is the consequence of this characteristic?
As a result, they cause fewer side effects associated with these receptors:
Postural hypotension.
Sedation.
Dry mouth.
Tricyclic depressants target serotonin reuptake while affecting muscarinic, α-adrenergic, and histamine H1 receptors.
What is the consequence of this characteristic?
As a result, they cause effects associated with these receptors:
Postural hypotension.
Sedation.
Dry mouth.
When do we use tricyclic antidepressants, MAO inhibitors, etc. to treat depression instead of SSRIs?
When the patient doesn’t respond to SSRIs.
Do SSRIs improve the mood shortly after they are taken?
No. It usually takes at least two weeks to improve mood, with maximum effects up to 12 weeks or more.
Why is the therapeutic effect of antidepressants delayed and not immediate?
Initially increased serotonin worsens symptoms by reducing its own release. However, over time, receptor desensitization improves serotonin transmission and mood.
Why shouldn’t the treatment of depression be less than 6 months?
The risk of relapse is greatest during the first 6 months after recovery.
Approximately 40% of depressed patients never respond to an antidepressant. Why?
Genetic factor.
What if a patient doesn’t respond to an antidepressant?
Patients who do not respond to one antidepressant may respond to another, and approximately 80% or more will respond to at least one antidepressant drug.
What are the therapeutic uses of SSRIs in addition to depression?
Obsessive compulsive disorder (fluoxetine).
Panic disorder.
Generalized anxiety disorder.
Post traumatic stress disorder.
Social anxiety disorder.
Premenstrual dysphoric disorder.
Bulimia nervosa (only fluoxetine!)
What are the extra therapeutic uses of fluoxetine?
Obsessive compulsive disorder.
Bulimia nervosa.
What are the pharmacokinetics of sertraline?
Only sertraline undergoes significant first-pass metabolism.
Why should we be careful when using fluoxetine if we plan to introduce a drug that interacts with it?
The metabolite of the s-enantiomer (s-norfluxoetine) is as potent as the parent compound, causing the drug to have a longer half-life (50 hours), so it is used once weekly.
The long half-life of fluoxetine can result in drug-drug interactions if a drug that interacts with fluoxetine is introduced too early. So caution should be used when fluoxetine is used.
How are SSRIs excreted?
Excretion of SSRIs is primarily through the kidneys, except for paroxetine and sertraline, which also undergo fecal secretion.
Which two SSRI drugs have a special excretion profile?
Paroxetine and sertraline, which also undergo fecal secretion in addition to kidney excretion.
Describe the drug-drug interaction profile of citalopram and escitalopram
Citalopram and escitalopram have the least effect on the cytochrome P450 system, so they have the most favorable profile regarding drug-drug interactions.
How does food affect the absorption of sertraline?
Food has little effect on the absorption of SSRIs except for sertraline, food increases its absorption.
Which SSRIs should be taken at night?
Paroxetine and fluvoxamine as they have a sedating effect. This can be advantageous if the patient has sleep disturbances.
Which SSRIs should be taken at daytime?
Fluoxetine and sertraline.
Which SSRIs should insomniacs and anxious people avoid?
Fluoxetine and sertraline.
Which SSRIs are recommended for fatigued, depressed patients?
Fluoxetine and sertraline, due to their energizing effect.
Discuss the sexual dysfunction side effect associated with SSRIs.
SSRIs commonly cause sexual dysfunction in the form of loss of libido and delayed ejaculation.
How is the sexual dysfunction side effect associated with SSRIs managed?
- Switch to a drug which has a more favorable sexual side effect profile, such as bupropion.
- Use of PDE inhibitors, such as sildenafil.
What happens when SSRIs are overdosed?
- Seizures.
- Serotonin syndrome:
- Hyperthermia.
- Muscle rigidity.
- Sweating.
- Clonic muscle twitching.
- Changes in mental status and vital signs (if used in conjugation with MAOIs).
Which SSRI is associated with weight gain?
Paroxetine.
How do SSRIs affect Parkinson patients?
SSRIs have been associated with extrapyramidal side effects, especially those with Parkinson’s disease, because they have an ability to block dopamine receptors.
What is the discontinuation syndrome associated with SSRIs?
A syndrome that occurs when the depressed patient stops taking SSRIs abruptly:
- Headache.
- Malaise.
- Flu-like symptoms.
- Agitation.
- Irritability.
- Nervousness.
- Sleep disturbances.
Which drug-drug interactions can cause serotonin syndrome when used with SSRIs?
- MAO inhibitors.
- Triptans.
Which drug-drug interaction is most serious for paroxetine?
Use of paroxetine with anesthetics can cause neuroleptic malignant syndrome.
How do SNRIs work?
They prevent the reuptake of serotonin and norepinephrine by blocking the transporters of these monoamines.
What are the most commonly used SNRIs?
Venlafaxine.
Desvenlafaxine.
Duloxetine.