• you are allergic to any ingredient in Lexapro
• you are taking citalopram
• you are taking or have taken a monoamine oxidase inhibitor (MAOI) (eg, phenelzine), selegiline, or St. John's wort within the last 14 days
• you are taking a fenfluramine derivative (eg, dexfenfluramine), an H₁ antagonist (eg, astemizole, terfenadine), nefazodone, pimozide, or sibutramine.

Contact your doctor or health care provider right away if any of these apply to you.

Some medical conditions may interact with Lexapro. Tell your doctor or pharmacist if you have any medical conditions, especially if any of the following apply to you:

• if you are pregnant, planning to become pregnant, or are breast-feeding
• if you are taking any prescription or nonprescription medicine, herbal preparation, or dietary supplement
• if you have allergies to medicines, foods, or other substances
• if you or a family member has a history of bipolar disorder (manic-depression), other mental or mood problems, suicidal thoughts or attempts, or alcohol or substance abuse
• if you have a history of seizures, liver problems, severe kidney problems, stomach or bowel bleeding, or metabolism problems
• if you are dehydrated, have low blood sodium levels, or drink alcohol
• if you will be having electroconvulsive therapy (ECT).

Some medicines may interact with Lexapro. Tell your health care provider if you are taking any other medicines, especially any of the following:

• Fenfluramine derivatives (eg, dexfenfluramine), linezolid, lithium, MAOIs (eg, phenelzine), metoclopramide, nefazodone, selegiline, serotonin 5-HT₁ receptor agonists (eg, sumatriptan), sibutramine, St. John's wort, or trazodone because severe side effects, such as a reaction that may include agitation, blood pressure changes, coma, confusion, delirium, fever, irritability, mental changes, and rigid muscles, may occur
• Anticoagulants (eg, warfarin), aspirin, or nonsteroidal anti-inflammatory drugs (NSAIDs) (eg, ibuprofen) because the risk of bleeding, including stomach bleeding, may be increased
• Diuretics (eg, furosemide, hydrochlorothiazide) because the risk of low blood sodium levels may be increased
• Tramadol because the risk of seizures may be increased
• H₁ antagonists (eg, astemizole, terfenadine) or phenothiazines (eg, chlorpromazine, thioridazine) because severe heart problems, including irregular heartbeat, may occur
• Carbamazepine or cyproheptadine because they may decrease Lexapro's effectiveness
• Clozapine, pimozide, risperidone, or tricyclic antidepressants (eg, amitriptyline) because the risk of their side effects may be increased by Lexapro.

This may not be a complete list of all interactions that may occur. Ask your health care provider if Lexapro may interact with other medicines that you take. Check with your health care provider before you start, stop, or change the dose of any medicine.

Important safety information:

• Lexapro may cause drowsiness or dizziness. These effects may be worse if you take it with alcohol or certain medicines. Use Lexapro with caution. Do not drive or perform other possible unsafe tasks until you know how you react to it.
• Do not drink alcohol while you are using Lexapro.
• Check with your doctor before you use medicines that may cause drowsiness (eg, sleep aids, muscle relaxers) while you are using Lexapro; it may add to their effects. Ask your pharmacist if you have questions about which medicines may cause drowsiness.
• One to 4 weeks may pass before your symptoms improve. Do NOT take more than the recommended dose, change your dose, or use Lexapro for longer than prescribed without checking with your doctor.
• Children, teenagers, and young adults who take Lexapro may be at increased risk for suicidal thoughts or actions. Watch all patients who take Lexapro closely. Contact the doctor at once if new, worsened, or sudden symptoms such as depressed mood; anxious, restless, or irritable behavior; panic attacks; or any unusual change in mood or behavior occur. Contact the doctor right away if any signs of suicidal thoughts or actions occur.
• Lexapro and a medicine called citalopram have the same active ingredient. Do not take Lexapro if you are also taking citalopram.
• If your doctor tells you to stop taking Lexapro, you will need to wait for several weeks before beginning to take certain other medicines (eg, MAOIs, nefazodone). Ask your doctor when you should start to take your new medicines after you have stopped taking Lexapro.
• Lexapro may rarely cause a prolonged, painful erection. This could happen even when you are not having sex. If this is not treated right away, it could lead to permanent sexual problems such as impotence. Contact your doctor right away if this happens.
• Serotonin syndrome is a possibly fatal syndrome that can be caused by Lexapro. Your risk may be greater if you take Lexapro with certain other medicines (eg, "triptans," MAOIs). Symptoms may include agitation; confusion; hallucinations; coma; fever; fast or irregular heartbeat; tremor; excessive sweating; and nausea, vomiting, or diarrhea. Contact your doctor at once if you have any of these symptoms.
• Neuroleptic malignant syndrome (NMS) is a possibly fatal syndrome that can be caused by Lexapro. Symptoms may include fever; stiff muscles; confusion; abnormal thinking; fast or irregular heartbeat; and sweating. Contact your doctor at once if you have any of these symptoms.
• Use Lexapro with caution in the elderly; they may be more sensitive to its effects, especially low blood sodium levels.
• Caution is advised when using Lexapro in children; they may be more sensitive to its effects, especially increased risk of suicidal thoughts or actions.
• Lexapro should be used with extreme caution in children younger 12 years; safety and effectiveness in these children have not been confirmed.
• Lexapro may cause weight changes. Children and teenagers may need regular weight and growth checks while they take Lexapro.
• Pregnancy and breast-feeding: Lexapro may cause harm to the fetus if it is used during the last 3 months of pregnancy. If you become pregnant, contact your doctor. You will need to discuss the benefits and risks of using Lexapro while you are pregnant. Lexapro is found in breast milk. Do not breastfeed while taking Lexapro.

Check with your doctor if any of these most common side effects persist or become bothersome:

Constipation; decreased sexual desire or ability; diarrhea; dizziness; drowsiness; dry mouth; headache; increased sweating; lightheadedness when you stand or sit up; loss of appetite; nausea; stomach upset; tiredness; trouble sleeping.

Seek medical attention right away if any of these severe side effects occur:

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); bizarre behavior; black or bloody stools; chest pain; confusion; decreased concentration; decreased coordination; fainting; fast or irregular heartbeat; hallucinations; memory loss; menstrual period changes; new or worsening agitation, panic attacks, aggressiveness, impulsiveness, irritability, hostility, exaggerated feeling of well-being, restlessness, or inability to sit still; persistent or severe ringing in the ears;persistent, painful erection; red, swollen, blistered, or peeling skin; seizures; severe or persistent anxiety or trouble sleeping; severe or persistent headache; stomach pain; suicidal thoughts or attempts; tremor; unusual bruising or bleeding; unusual or severe mental or mood changes; unusual weakness; vision changes; worsening of depression.

This is not a complete list of all side effects that may occur. If you have questions about side effects, contact your health care provider.