Mechanism of action
Sertraline selectively inhibits the presynaptic serotonin transporter (SERT), blocking the reuptake of serotonin (5-HT) from the synaptic cleft into the presynaptic neuron. This increases the availability and duration of action of serotonin at postsynaptic receptors in the central nervous system.
The therapeutic effects in depression and anxiety disorders are thought to result from enhanced serotonergic neurotransmission in key brain regions including the prefrontal cortex, hippocampus, and amygdala. The antidepressant effect typically requires 4-6 weeks of treatment, reflecting the time needed for downstream adaptive changes including desensitization of presynaptic 5-HT1A autoreceptors and neuroplastic changes.
Sertraline has minimal affinity for other neurotransmitter receptors compared to tricyclic antidepressants, including negligible effects on muscarinic cholinergic, histaminergic H1, or alpha-adrenergic receptors. It does possess weak dopamine reuptake inhibition at higher doses, which may contribute to its activating profile. Sertraline also inhibits sigma-1 receptors, though the clinical significance remains uncertain.
- Sertraline is an SSRI that selectively inhibits serotonin reuptake at the presynaptic terminal.
- Black box warning: increased suicidal thinking in patients under age 24 during initial treatment.
- Sertraline has the highest rate of GI side effects (especially diarrhea) among SSRIs.
- Absolute contraindications: concurrent MAOI use (risk of serotonin syndrome) and pimozide (QT prolongation).
- Serotonin syndrome triad: mental status changes, autonomic instability, neuromuscular hyperactivity.
- SSRIs increase bleeding risk by impairing platelet aggregation; caution with NSAIDs and anticoagulants.
- Sertraline is considered safe in cardiovascular disease and post-MI patients (SADHART trial).
- Therapeutic effects take 4-6 weeks; full response may require 6-8 weeks or longer of treatment.
Indications
Sertraline is FDA-approved for the following conditions:
- Major depressive disorder (MDD) in adults and pediatric patients (ages 6 and older for OCD only)
- Obsessive-compulsive disorder (OCD) in adults and children
- Panic disorder with or without agoraphobia
- Post-traumatic stress disorder (PTSD)
- Social anxiety disorder (social phobia)
- Premenstrual dysphoric disorder (PMDD)
Off-label uses
Sertraline is commonly used off-label for generalized anxiety disorder, premature ejaculation, and bulimia nervosa. It has also been studied in the treatment of hot flashes in menopausal women and chronic pain syndromes with comorbid depression.
Among SSRIs, sertraline is often preferred in patients with cardiovascular disease due to its favorable cardiac safety profile. It is also commonly chosen for OCD due to robust evidence supporting efficacy at higher doses.
Pharmacokinetics
Absorption: Sertraline is well absorbed after oral administration, with peak plasma concentrations reached in 4.5-8.4 hours. Food increases the bioavailability, so it is often recommended to take with meals.
Distribution: Sertraline is highly protein-bound (approximately 98%) and has a large volume of distribution. It crosses the blood-brain barrier and is distributed into breast milk in small amounts.
Metabolism: Sertraline undergoes extensive hepatic first-pass metabolism primarily via N-demethylation to desmethylsertraline, a significantly less active metabolite. The enzyme CYP2C19 is primarily responsible, with contributions from CYP2B6, CYP2C9, and CYP3A4. Sertraline is a mild inhibitor of CYP2D6.
Elimination: The elimination half-life of sertraline is approximately 26 hours, allowing once-daily dosing. Steady-state concentrations are achieved in 1 week. Metabolites are excreted in urine and feces in roughly equal proportions.
Age, hepatic impairment, and mild to moderate renal impairment affect clearance, but dosing adjustments typically follow the product label and clinical response rather than fixed formulas.
Adverse effects
Sertraline is generally well tolerated, but adverse effects occur in a significant proportion of patients, particularly during the first few weeks of treatment.
Common adverse effects
- Gastrointestinal: Nausea, diarrhea, dyspepsia, and decreased appetite (sertraline has the highest rate of diarrhea among SSRIs)
- Central nervous system: Insomnia, somnolence, dizziness, headache, tremor, fatigue
- Sexual dysfunction: Delayed ejaculation, decreased libido, anorgasmia (affects 30-60% of patients)
- Other: Dry mouth, sweating, weight changes (usually modest weight gain over time)
Serious adverse effects
Serotonin syndrome: A rare but potentially life-threatening condition caused by excessive serotonergic activity. Features include altered mental status, autonomic instability (hyperthermia, tachycardia, labile blood pressure), and neuromuscular hyperactivity (clonus, hyperreflexia, rigidity). Risk is highest when combining sertraline with other serotonergic agents (MAOIs, tramadol, triptans, St. John's wort).
Hyponatremia: SSRIs can cause syndrome of inappropriate antidiuretic hormone secretion (SIADH), particularly in elderly patients. Monitor sodium levels in at-risk populations.
Bleeding risk: SSRIs interfere with platelet serotonin uptake, increasing the risk of bleeding, especially when combined with NSAIDs, aspirin, or anticoagulants.
QT prolongation: Although sertraline has minimal cardiac effects compared to citalopram, high doses may prolong the QT interval in susceptible individuals.
Suicidality: FDA black box warning for increased risk of suicidal thinking and behavior in children, adolescents, and young adults (up to age 24) during the initial months of treatment. Close monitoring is essential, particularly during dose changes.
Withdrawal syndrome: Abrupt discontinuation can cause dizziness, paresthesias, anxiety, nausea, and flu-like symptoms. Taper gradually when discontinuing.
Contraindications and warnings
Absolute contraindications
- Concomitant use with monoamine oxidase inhibitors (MAOIs) or within 14 days of MAOI discontinuation (risk of serotonin syndrome)
- Use of pimozide (sertraline inhibits CYP2D6 and can increase pimozide levels, causing QT prolongation and arrhythmias)
- Known hypersensitivity to sertraline or any formulation component
- Concurrent use with disulfiram (oral concentrate contains alcohol)
Warnings and precautions
Bipolar disorder screening: SSRIs can precipitate manic or hypomanic episodes in patients with undiagnosed bipolar disorder. Screen for personal or family history of bipolar disorder before initiating treatment.
Angle-closure glaucoma: SSRIs can cause mydriasis, triggering angle-closure glaucoma in anatomically susceptible individuals.
Seizure disorder: Use with caution in patients with a history of seizures, as SSRIs may lower the seizure threshold.
Hepatic impairment: Reduced clearance occurs in patients with cirrhosis; lower doses may be necessary.
Pregnancy and lactation: Sertraline is pregnancy category C (now classified under the Pregnancy and Lactation Labeling Rule). Use during the third trimester has been associated with neonatal complications including persistent pulmonary hypertension of the newborn (PPHN), though absolute risk remains low. Weigh risks and benefits carefully. Sertraline is excreted in breast milk in small amounts but is often considered compatible with breastfeeding; discuss with the patient.
Drug interactions
Sertraline has a moderate potential for drug interactions, primarily through its mild inhibition of CYP2D6 and its serotonergic effects.
Major interactions
MAOIs: Absolute contraindication due to risk of fatal serotonin syndrome. Allow 14 days washout after MAOI discontinuation and 14 days after stopping sertraline before starting an MAOI.
Pimozide: Contraindicated due to increased pimozide levels and risk of QT prolongation and torsades de pointes.
Other serotonergic agents: Concurrent use with tramadol, triptans, linezolid, methylene blue, fentanyl, dextromethorphan, or St. John's wort increases serotonin syndrome risk. Use caution and monitor closely.
Anticoagulants and antiplatelets: NSAIDs, aspirin, warfarin, and other anticoagulants increase bleeding risk when combined with SSRIs. Monitor INR closely in patients on warfarin.
Moderate interactions
CYP2D6 substrates: Sertraline is a weak-to-moderate CYP2D6 inhibitor and can increase levels of drugs metabolized by this enzyme, including metoprolol, propafenone, flecainide, atomoxetine, desipramine, and risperidone. Monitor for increased effects or toxicity.
Drugs prolonging QT interval: Use caution when combining sertraline with other QT-prolonging agents (antiarrhythmics, antipsychotics, macrolide antibiotics).
CNS depressants: Alcohol and benzodiazepines may have additive sedative effects, though sertraline is generally less sedating than other antidepressants.
Highly protein-bound drugs: Sertraline may displace other highly protein-bound drugs (warfarin, phenytoin), though clinical significance is usually minimal.
Clinical pearls
- Onset of action: Inform patients that therapeutic benefit may not be apparent for 4-6 weeks and that full response may take 6-8 weeks or longer. This improves adherence and reduces premature discontinuation.
- GI side effects: Sertraline causes more diarrhea than other SSRIs. Taking with food and starting at a lower dose can mitigate this. GI side effects often improve after the first 1-2 weeks.
- Sexual dysfunction management: Sexual side effects are common and a frequent reason for non-adherence. Strategies include dose reduction, drug holidays (not recommended due to withdrawal risk), switching to bupropion or mirtazapine, or adding bupropion. Always discuss this proactively.
- Cardiac safety: Sertraline is considered one of the safest SSRIs in patients with cardiovascular disease, including post-myocardial infarction. The SADHART trial demonstrated safety in this population.
- Pediatric use: Sertraline is FDA-approved for OCD in children aged 6 and older. It is commonly used off-label for pediatric depression and anxiety, though the black box warning regarding suicidality applies.
- Tapering: When discontinuing, taper gradually over several weeks to minimize withdrawal symptoms. Patients on sertraline may experience fewer discontinuation symptoms than those on shorter half-life SSRIs like paroxetine, but tapering is still important.
- CYP2D6 inhibition: While weaker than paroxetine or fluoxetine, sertraline's CYP2D6 inhibition is clinically relevant at higher doses. Be alert to interactions with tamoxifen (reduced conversion to active metabolite), codeine, and tramadol (reduced analgesic efficacy).
- OCD dosing: Higher doses are typically required for OCD compared to depression. Response in OCD may take longer (10-12 weeks).
- Alcohol: Advise patients to avoid or limit alcohol, as it may worsen CNS side effects and depression.
Practice questions
1. A 32-year-old woman with major depressive disorder is started on sertraline. Four weeks later, she reports significant improvement in mood and energy but complains of inability to achieve orgasm, which is affecting her relationship. She has no other medical conditions and takes no other medications. Which of the following is the most appropriate next step in management?
2. A 28-year-old man taking sertraline for panic disorder presents to the emergency department with agitation, confusion, diaphoresis, and tremor. On examination, he has hyperreflexia, myoclonus, and a temperature of 38.9°C (102°F). His heart rate is 118/min and blood pressure is 162/95 mmHg. He admits to taking tramadol that his friend gave him for back pain three days ago. Which of the following is the most likely diagnosis?
3. A 68-year-old woman with depression has been taking sertraline for three weeks. She now presents with lethargy, nausea, and confusion. Laboratory studies show: serum sodium 118 mEq/L (normal 135-145), serum osmolality 245 mOsm/kg (normal 275-295), urine osmolality 620 mOsm/kg, and urine sodium 48 mEq/L. She takes no other medications and has normal thyroid and adrenal function. Which of the following is the most likely cause of her hyponatremia?
Frequently asked questions
How does sertraline work?
Sertraline works by selectively inhibiting the reuptake of serotonin from the synaptic cleft into the presynaptic neuron. This increases the concentration and duration of action of serotonin at postsynaptic receptors in the brain. The enhanced serotonergic neurotransmission is thought to improve mood, reduce anxiety, and alleviate obsessive-compulsive symptoms, though the full therapeutic effect typically takes 4-6 weeks to develop as downstream neuroplastic changes occur.
What are the side effects of sertraline?
Common side effects of sertraline include gastrointestinal upset (especially diarrhea and nausea), sexual dysfunction (delayed ejaculation, decreased libido, anorgasmia), insomnia or somnolence, headache, dizziness, and increased sweating. Sertraline causes more diarrhea than other SSRIs. Serious but rare side effects include serotonin syndrome, hyponatremia (especially in elderly patients), increased bleeding risk, and QT prolongation at high doses. A black box warning exists for increased suicidal thinking in patients under 24 years old during initial treatment.
Is sertraline a controlled substance?
No, sertraline is not a controlled substance. It is a prescription antidepressant in the SSRI class and does not have abuse potential or cause physical dependence in the way that controlled substances do. However, abrupt discontinuation can cause withdrawal symptoms (dizziness, paresthesias, anxiety, nausea), so it should be tapered gradually when stopping. Sertraline does not produce euphoria or have reinforcing properties that would lead to misuse.
Sertraline vs escitalopram — what is the difference?
Both sertraline and escitalopram are SSRIs used for depression and anxiety disorders, but they have some differences. Sertraline causes more gastrointestinal side effects, particularly diarrhea, while escitalopram is generally better tolerated with fewer GI complaints. Sertraline has weak dopamine reuptake inhibition and may be slightly more activating. Escitalopram is considered the most selective SSRI with fewer drug interactions. Escitalopram has a greater risk of QT prolongation at higher doses. Both are effective first-line agents, and choice often depends on patient-specific factors and side effect profile.
Can you take sertraline while pregnant?
Sertraline use during pregnancy requires careful consideration of risks and benefits. It is classified as pregnancy category C (now under the Pregnancy and Lactation Labeling Rule). Some studies suggest a small increased risk of persistent pulmonary hypertension of the newborn (PPHN) with third-trimester use, and neonatal adaptation syndrome (jitteriness, respiratory distress) can occur. However, untreated maternal depression also poses risks to both mother and fetus. Many clinicians consider sertraline among the better-studied SSRIs in pregnancy. The decision should be individualized with shared decision-making between patient and provider.
Conditions it is used for
Related drugs
Sources and further reading
DailyMed (FDA labels)StatPearls (NCBI Bookshelf)MedlinePlusWHO ATC/DDD index: N06AB06
Educational content for medical students, prepared by the WhiteCoat Pro editorial team with AI assistance; every page is reviewed by a second AI model for factual errors. It is not medical advice and does not replace the product label, local guidelines or a clinician.