Lithium - Paxil (Paroxetine) Interaction

Interaction Details

Paroxetine is classified as belonging to the following category: Serotonergic Drugs

Theoretically, taking lithium supplements with serotonergic drugs might both mask and increase the risk of serotonin syndrome.
In a case report, a 67-year-old female with depression and bipolar disorder using lithium in combination with selective serotonin reuptake inhibitors (SSRIs) and other medications developed serotonin syndrome with symptoms of deep tendon hyperreflexia, muscle rigidity, tremor, and hyperthermia. However, agitation, one classical symptom of serotonin syndrome, was lacking. This was thought to be due to masking by lithium toxicity. Lithium can increase serotonin levels, thus, combining serotonergic drugs with lithium might increase the risk of serotonergic side effects including serotonin syndrome and cerebral vasoconstrictive disorders. It is unclear if this interaction would occur with the smaller doses found in lithium supplements.

Interaction Rating

Likelihood of Occurrence

Interaction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.

References

• Martindale W. Martindale the Extra Pharmacopoeia. Pharmaceutical Press, 1999.
• McEvoy GK, ed. AHFS Drug Information. Bethesda, MD: American Society of Health-System Pharmacists, 1998.
• Landa E, Wagner S, Makkar A, Liu A, Jung D. An atypical presentation of serotonin syndrome. Cureus. 2021;13(2):e13377.

Paroxetine Overview

• Paroxetine tablets, suspension (liquid), and extended-release (long-acting) tablets are used to treat depression, panic disorder (sudden, unexpected attacks of extreme fear and worry about these attacks), and social anxiety disorder (extreme fear of interacting with others or performing in front of others that interferes with normal life). Paroxetine tablets and suspension are also used to treat obsessive-compulsive disorder (bothersome thoughts that won't go away and the need to perform certain actions over and over), generalized anxiety disorder (GAD; excessive worrying that is difficult to control), and posttraumatic stress disorder (disturbing psychological symptoms that develop after a frightening experience). Paroxetine extended-release tablets are also used to treat premenstrual dysphoric disorder (PMDD, physical and psychological symptoms that occur before the onset of the menstrual period each month). Paroxetine capsules (Brisdelle) are used to treat hot flashes (sudden feelings of warmth, especially in the face, neck, and chest) in women who are experiencing menopause (stage of life when menstrual periods become less frequent and stop and women may experience other symptoms and body changes). Paroxetine is in a class of medications called selective serotonin-reuptake inhibitors (SSRIs). It treats depression and other mental illnesses by increasing the amount of serotonin, a natural substance in the brain that helps maintain mental balance. There is not enough information available at this time to know how paroxetine works to treat hot flashes.

Lithium - More Interactions

Lithium interacts with 511 drugs

Interaction Rating Key

These severity listings are for informational use only. Never start, stop or otherwise change your therapy before speaking with your provider.