What are the reactions to Selective Serotonin Reuptake Inhibitor (SSRI) drugs?

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Last updated: February 28, 2025View editorial policy

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From the Guidelines

Selective serotonin reuptake inhibitors (SSRIs) can cause several common side effects and reactions, including nausea, headache, insomnia, drowsiness, dry mouth, dizziness, and sexual dysfunction, and more serious reactions such as increased suicidal thoughts, serotonin syndrome, and withdrawal symptoms. These medications, including fluoxetine (Prozac), sertraline (Zoloft), escitalopram (Lexapro), and paroxetine (Paxil), typically cause these side effects during the first few weeks of treatment, with most side effects diminishing over time as the body adjusts to the medication 1. Some key points to consider when prescribing SSRIs include:

  • Starting at low doses and gradually increasing under medical supervision to minimize the risk of adverse effects 1
  • Avoiding sudden discontinuation of SSRIs to prevent withdrawal symptoms 1
  • Monitoring patients closely for signs of increased suicidal thoughts or behaviors, particularly in young adults and adolescents 1
  • Being aware of the potential for serotonin syndrome, a rare but serious condition caused by elevated brain serotonin levels, which can be triggered by combining serotonergic medications 1
  • Considering the potential for drug-drug interactions, particularly with other serotonergic agents, and adjusting treatment accordingly 1

In terms of specific SSRIs, some have been associated with a higher risk of certain side effects, such as:

  • Paroxetine, which has been linked to a higher risk of suicidal thinking or behavior compared to other SSRIs 1
  • Citalopram, which can cause QT prolongation associated with Torsade de Pointes, ventricular tachycardia, and sudden death at daily doses exceeding 40 mg/d 1
  • Fluvoxamine, which may have a greater potential for drug-drug interactions due to its inhibition of multiple cytochrome P450 enzymes 1

Overall, the key to safe and effective use of SSRIs is careful patient selection, gradual dose titration, and close monitoring for adverse effects 1.

From the FDA Drug Label

Neonates exposed to Prozac and other SSRIs or serotonin and norepinephrine reuptake inhibitors (SNRIs), late in the third trimester have developed complications requiring prolonged hospitalization, respiratory support, and tube feeding. Such complications can arise immediately upon delivery Reported clinical findings have included respiratory distress, cyanosis, apnea, seizures, temperature instability, feeding difficulty, vomiting, hypoglycemia, hypotonia, hypertonia, hyperreflexia, tremor, jitteriness, irritability, and constant crying. Neonates exposed to sertraline and other SSRIs or serotonin and norepinephrine reuptake inhibitors (SNRIs), late in the third trimester have developed complications requiring prolonged hospitalization, respiratory support, and tube feeding. Such complications can arise immediately upon delivery Reported clinical findings have included respiratory distress, cyanosis, apnea, seizures, temperature instability, feeding difficulty, vomiting, hypoglycemia, hypotonia, hypertonia, hyperreflexia, tremor, jitteriness, irritability, and constant crying.

The reactions to Selective Serotonin Reuptake Inhibitor (SSRI) drugs include:

  • Respiratory distress
  • Cyanosis
  • Apnea
  • Seizures
  • Temperature instability
  • Feeding difficulty
  • Vomiting
  • Hypoglycemia
  • Hypotonia
  • Hypertonia
  • Hyperreflexia
  • Tremor
  • Jitteriness
  • Irritability
  • Constant crying 2 3

From the Research

Adverse Reactions to Selective Serotonin Reuptake Inhibitors (SSRIs)

  • The most commonly reported adverse reactions to SSRIs include neurological symptoms (22.4%), psychiatric symptoms (19.5%), and gastrointestinal symptoms (18.0%) 4.
  • Dermatological symptoms (11.4%) and general symptoms (9.8%) are also frequently reported 4.
  • Specific adverse reactions that are more commonly associated with certain SSRIs include:
    • Gastrointestinal symptoms with fluvoxamine 4, 5
    • Psychiatric symptoms with sertraline 4
    • Dermatological symptoms with fluoxetine 4
  • Severe adverse reactions, such as seizures, hyponatraemia, and the serotonin syndrome, are rarely reported 4, 6, 7.
  • Certain patient populations, such as the elderly and those with comorbid medical conditions, may be more susceptible to adverse reactions 6, 7.

Risk Factors for Adverse Reactions

  • Concomitant use of other medications, particularly those that interact with SSRIs, can increase the risk of adverse reactions 6, 7.
  • Patients who are taking multiple medications, including alcohol, may be at higher risk for adverse reactions 6.
  • Certain genetic polymorphisms may also contribute to the risk of adverse reactions, although further research is needed to fully understand this relationship 8.

Specific Adverse Reactions

  • Cardiovascular adverse reactions, such as rhythm disturbances and blood pressure perturbations, can occur with SSRI use 6, 7.
  • Neurological adverse reactions, such as agitation, hyponatremia, and the serotonin syndrome, can also occur 4, 6, 7.
  • Gastrointestinal adverse reactions, such as nausea and diarrhea, are common with SSRI use 4, 5, 7.
  • Dermatological adverse reactions, such as rash and urticaria, can occur with SSRI use 4, 5, 7.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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