广谱AED新药。它不同于其他西坦类益智药物，而特别选择性与中枢突触囊泡(synapse vesicles)-SV2A结合,具有抑制点燃效应及抗癫癎作用，可用于局灶性发作继发全面性发作,全面性发作, 肌阵挛等各类型难治性癫癎与癫癎性脑病(如大田原综合征,IS,LGS),并对认知功能影响小。它呈理想的线性动力学（linear kinetics），口服吸收迅速(Tmax 1.3 h)而完全，1~3d快速起效，半衰期6h~8 h，CSF半衰期15h,95%(2/3以原型)经肾脏排出(2 d),清除率高。不依耐细胞色素P450,与其他AEDs(VPA,CBZ,PTH)无相互作用。小儿20~40 mg/(kg·d),成人0.5 g,2/d。耐受性高，不良反应少，可有嗜睡、头晕、食欲不振等，撤药率15%。LEV单药治疗1年，完全控制率在56.6%以上,难治性癫癎完全控制率26%。3年保留率58%,撤药率15%。左乙拉西坦50mg×30片/盒:RMB186; 500mg×30片/盒:RMB310。在当前的情况下，选药还要考虑药物经济学（pharmacoecnomics）即（namely）成本、效益比（cost- effectiveness）或性价比（E/C），以患者经济承受力来考虑贱贵两套AEDs治疗方案。
Why is this medication prescribed?
Levetiracetam is used in combination with other medications to treat certain types of seizures in people with epilepsy. Levetiracetam is in a class of medications called anticonvulsants. It works by decreasing abnormal excitement in the brain.
How should this medicine be used?
Levetiracetam comes as a solution (liquid) and a tablet to take by mouth. It is usually taken twice a day, once in the morning and once at night, with or without food. Try to take levetiracetam at around the same times every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take levetiracetam exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.
Swallow the tablets whole; do not split, chew, or crush them.
If you are taking the oral solution, do not use a household spoon to measure your dose. You might not get the right amount of medication. Ask your doctor or pharmacist to recommend a medicine dropper, spoon, cup, or syringe and to show you how to use it to measure your medication.
Your doctor may start you on a low dose of levetiracetam and gradually increase your dose, not more often than once every 2 weeks.
Levetiracetam controls epilepsy but does not cure it. Continue to take levetiracetam even if you feel well. Do not stop taking levetiracetam without talking to your doctor. If you suddenly stop taking levetiracetam, your seizures may become worse. Your doctor will probably decrease your dose gradually.
Other uses for this medicine
This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.
What special precautions should I follow?
Before taking levetiracetam,
tell your doctor and pharmacist if you are allergic to levetiracetam or any other medications.
tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking. Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
tell your doctor if you have or have ever had kidney disease.
tell your doctor if you are pregnant or plan to become pregnant. If you become pregnant while taking levetiracetam, call your doctor. Do not breast-feed while you are taking levetiracetam
you should know that levetiracetam may make you dizzy or drowsy. Do not drive a car or operate machinery until you know how this medication affects you.
you should know that your mental health may change in unexpected ways, and you may become suicidal (thinking about harming or killing yourself or planning or trying to do so) while you are taking levetiracetam for the treatment of epilepsy, mental illness, or other conditions. A small number of adults and children 5 years of age and older who took antiepileptics such as levetiracetam during clinical studies were found to be twice as likely to become suicidal than people who did not take the medication. This increased risk of suicidal behavior was seen as early as one week after starting the medication. You, your family, or your caregiver should call your doctor right away if you experience any of the following symptoms: anxiety, agitation, hostility, mania (frenzied, abnormally excited mood), talking or thinking about wanting to hurt yourself or end your life, withdrawing from friends and family, new or worsening depression, preoccupation with death and dying, or giving away prized possessions. Be sure that your family or caregiver knows which symptoms may be serious so they can call the doctor if you are unable to seek treatment on your own.
What special dietary instructions should I follow?
Unless your doctor tells you otherwise, continue your normal diet.
What should I do if I forget a dose?
If it has only been a few hours since the time you were scheduled to take the dose, take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.
What side effects can this medication cause?
Levetiracetam may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:
drowsiness ,weakness,unsteady walking ,coordination problems ,headache ,pain ,forgetfulness ,anxiety ,agitation or hostility ,dizziness ,moodiness ,nervousness ,numbness, burning, or tingling in the hands or feet ,loss of appetite , vomiting ,diarrhea ,constipation,changes in skin color ,Some side effects can be serious. If you experience any of the following symptoms, call your doctor immediately: ,depression ,hallucinating (hearing voices or seeing visions that do not exist),thoughts of killing yourself , seizures that are worse or different than the seizures you had before ,fever, sore throat, and other signs of infection ,double vision,itching ,rash ,swelling of the face .
Levetiracetam may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.
If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online [at http://www.fda.gov/MedWatch/index.html] or by phone [1-800-332-1088].
What storage conditions are needed for this medicine?
Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom). Throw away any medication that is outdated or no longer needed. Talk to your pharmacist about the proper disposal of your medication.
In case of emergency/overdose
In case of overdose, call your local poison control center at 1-800-222-1222. If the victim has collapsed or is not breathing, call local emergency services at 911.
Symptoms of overdose may include: drowsiness agitation aggression decreased consciousness or loss of consciousness difficulty breathing
What other information should I know?
Keep all appointments with your doctor.
Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.
It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.