Lexapro (escitalopram) is a commonly prescribed Selective Serotonin Reuptake Inhibitor (SSRI). This drug is primarily used to manage major depressive disorder and generalized anxiety disorder by targeting chemical messengers in the brain. Healthcare providers individualize the daily dosage based on the patient’s condition, response to treatment, and overall health profile. Taking a dose higher than prescribed, whether accidentally or intentionally, can lead to adverse effects ranging from uncomfortable to life-threatening.
The Role of Serotonin in High Doses
Lexapro’s mechanism of action centers on the neurotransmitter serotonin, which regulates mood, sleep, and digestion. Normally, after serotonin sends a signal, it is quickly reabsorbed by the transmitting neuron in a process called reuptake. Lexapro works by blocking the protein responsible for this reuptake, known as the serotonin transporter (SERT).
By inhibiting reuptake, Lexapro increases the concentration of serotonin between neurons. When the dosage is too high, this blockade becomes excessive, leading to an overwhelming availability of serotonin in the central nervous system. This sudden, excessive surge in serotonin activity is the underlying cause of the toxicity seen with acute overdose, as the body’s systems become overstimulated.
Signs of Acute Overdose and Toxicity
The most severe and immediate consequence of an acute overdose is Serotonin Syndrome, a potentially life-threatening condition resulting from excessive serotonergic activity. Symptoms can appear rapidly, often within hours of ingestion, and are grouped into three main categories.
The first category involves changes in mental status and behavior, including confusion, agitation, and delirium. Individuals may also experience hallucinations or extreme restlessness, reflecting the overstimulation of serotonin receptors.
Another category encompasses autonomic instability, where the involuntary nervous system goes into overdrive. This manifests as a rapid heart rate (tachycardia), sudden fluctuations in blood pressure, and a high body temperature (hyperthermia). Profuse sweating and dilated pupils are also common signs.
The third category includes pronounced neuromuscular effects characteristic of serotonin toxicity. These symptoms include tremors, muscle rigidity, and hyperreflexia (an exaggerated response in the body’s reflexes). In severe cases, patients may experience a lack of coordination or convulsions.
Side Effects of Chronically Elevated Dosing
Taking a Lexapro dose that is moderately too high over an extended period leads to persistent side effects distinct from an acute overdose crisis. These effects often necessitate a dose reduction because they significantly impair the patient’s quality of life.
One common manifestation is persistent gastrointestinal distress. Patients frequently report severe nausea, vomiting, or diarrhea, which can become debilitating.
Neurological side effects include debilitating insomnia, agitation, or a restless inability to sit still. Paradoxically, increased anxiety or panic attacks can occur, even though the medication is intended to treat these very conditions.
Sexual dysfunction is another frequent issue with elevated dosing. This can involve a decreased sex drive, difficulty achieving orgasm (anorgasmia), or delayed ejaculation in males. These sustained side effects signal a negative reaction to the chronic presence of an excessive level of the medication.
Immediate Action and Clinical Treatment
If an acute overdose or the onset of Serotonin Syndrome is suspected, immediate action is paramount. The first step is to call emergency medical services or contact a local poison control center. Providing specific information, such as the amount ingested, the time it was taken, and any other substances involved, can significantly aid medical professionals.
In a clinical setting, treatment focuses on supportive care and stabilizing the patient’s vital signs. This includes continuous monitoring of heart rate, blood pressure, and body temperature. Intravenous fluids may be administered to maintain hydration and correct blood pressure issues.
Specific medical interventions may be used to manage the severe symptoms of toxicity. Activated charcoal may be given if the ingestion was recent to help prevent further drug absorption. Agitation and severe muscle symptoms are often managed using sedatives like benzodiazepines. In severe cases, a serotonin antagonist medication, such as cyproheptadine, may be used to block excessive serotonin activity.