From the FDA Drug Label
5.1 Coadministration with Other Drug Products for Weight Loss Phentermine is indicated only as short-term (a few weeks) monotherapy for the management of exogenous obesity The safety and efficacy of combination therapy with phentermine and any other drug products for weight loss including prescribed drugs, over-the-counter preparations, and herbal products, or serotonergic agents such as selective serotonin reuptake inhibitors (e.g., fluoxetine, sertraline, fluvoxamine, paroxetine), have not been established. Therefore, coadministration of phentermine and these drug products is not recommended.
The FDA drug label warns against the coadministration of phentermine with serotonergic agents, such as selective serotonin reuptake inhibitors (SSRIs), including escitalopram (Lexapro).
- The safety and efficacy of combination therapy with phentermine and SSRIs have not been established.
- Coadministration of phentermine and SSRIs is not recommended 1 1.
From the Research
There are significant interactions between Lexapro (escitalopram) and phentermine that could potentially be dangerous, and these medications should generally not be taken together due to the risk of serotonin syndrome, a potentially life-threatening condition. The most recent study 2 from 2023 highlights the potential for drug-drug interactions with phentermine, including severe interactions that could lead to adverse drug reactions. Although this study does not specifically mention Lexapro, the risk of serotonin syndrome is a well-known concern when combining medications that affect serotonin levels, such as SSRIs like Lexapro and stimulants like phentermine. Key points to consider:
- Lexapro is a selective serotonin reuptake inhibitor (SSRI) antidepressant that increases serotonin levels in the brain.
- Phentermine is a stimulant used for weight loss that can also affect serotonin levels.
- When combined, they can cause excessive serotonin accumulation, leading to symptoms such as agitation, confusion, rapid heart rate, high blood pressure, dilated pupils, muscle rigidity, tremor, excessive sweating, diarrhea, and in severe cases, seizures or loss of consciousness. If you are currently taking Lexapro and considering phentermine, or vice versa, you should consult with your healthcare provider to discuss alternative weight management options that don't carry this interaction risk. Never stop taking Lexapro suddenly without medical supervision, as this can cause withdrawal symptoms. Your doctor might suggest alternative weight management approaches or medications that are safer to use alongside your antidepressant.