Phenobarbital

This information from Lexicomp^® explains what you need to know about this medication, including what it’s used for, how to take it, its side effects, and when to call your healthcare provider.

Brand Names: US

Sezaby

What is this drug used for?

• It is used to help control certain kinds of seizures.
• It is used to treat anxiety.
• It is used to treat sleep problems.
• It may be given to your child for other reasons. Talk with the doctor.

What do I need to tell the doctor BEFORE my child takes this drug?

All products:

• If your child is allergic to this drug; any part of this drug; or any other drugs, foods, or substances. Tell the doctor about the allergy and what signs your child had.
• If your child has any of these health problems: Liver disease or breathing problems like shortness of breath.
• If your child has ever had porphyria.
• If your child has any of these health problems: Heart problems like heart failure or a certain type of chest pain (unstable angina), slow or abnormal heartbeat (like long QT on ECG), kidney disease, low thyroid function, or a very narrow heart valve (aortic stenosis).
• If your child has had a recent heart attack.
• If your child is taking any drugs that can cause a certain type of heartbeat that is not normal (prolonged QT interval). There are many drugs that can do this. Ask the doctor or pharmacist if you are not sure.

Injection:

• If the patient is a newborn or infant. Some products may have benzyl alcohol. In large amounts, benzyl alcohol may cause severe and sometimes deadly side effects in newborns or infants. The doctor may decide the benefits of taking this drug outweigh the risks. Talk with the doctor if you have questions about giving this drug to your child.

This is not a list of all drugs or health problems that interact with this drug.

Tell the doctor and pharmacist about all of your child’s drugs (prescription or OTC, natural products, vitamins) and health problems. You must check to make sure that it is safe to give this drug with all of your child’s other drugs and health problems. Do not start, stop, or change the dose of any drug your child takes without checking with the doctor.

What are some things I need to know or do while my child takes this drug?

For all uses of this drug:

• Tell all of your child’s health care providers that your child is taking this drug. This includes your child’s doctors, nurses, pharmacists, and dentists.
• The risk of dependence and withdrawal are raised the longer your child takes this drug and the higher the dose. Talk to the doctor before you lower the dose or stop giving this drug. You will need to follow the doctor’s instructions. Lowering the dose or stopping this drug all of a sudden may cause withdrawal. This can be life-threatening. Get medical help right away if your child has any bad effects.
• If your child has been taking this drug for a long time or at high doses, it may not work as well and your child may need higher doses to get the same effect. This is known as tolerance. Call the doctor if this drug stops working well. Do not give more than ordered.
• Have blood work checked if your child is on this drug for a long time. Talk with your child’s doctor.
• Have your child avoid tasks or actions that call for alertness until you see how this drug affects your child. These are things like riding a bike, playing sports, or using items such as scissors, lawnmowers, electric scooters, toy cars, or motorized vehicles.
• Alcohol may interact with this drug. Be sure your child does not drink alcohol.
• Talk with your child’s doctor before your child uses marijuana, other forms of cannabis, or prescription or OTC drugs that may slow your child’s actions.
• If the patient is a child, use this drug with care. The risk of some side effects may be higher in children.

If your child is or may be sexually active:

• Birth control pills and other hormone-based birth control may not work as well to prevent pregnancy. Be sure your child uses some other kind of birth control also, like a condom, when taking this drug.

If your child is pregnant or breast-feeding a baby:

• This drug may cause harm to the unborn baby if your child takes it during pregnancy. If your child is pregnant or gets pregnant while taking this drug, call the doctor right away.
• Taking this drug in the third trimester of pregnancy may lead to side effects or withdrawal in the newborn.
• Tell the doctor if your child is breast-feeding a baby. You will need to talk about any risks to the baby.

For seizures:

• If seizures are different or worse after starting this drug, talk with the doctor.

What are some side effects that I need to call my child’s doctor about right away?

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your child’s doctor or get medical help right away if your child has any of the following signs or symptoms that may be related to a very bad side effect:

All products:

• Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
• Feeling confused.
• Change in balance.
• Muscle spasm.
• Bad dreams.
• Restlessness.
• Hallucinations (seeing or hearing things that are not there).
• Shortness of breath.
• Slow heartbeat.
• Feeling very tired or weak.
• Severe dizziness or passing out.
• A severe skin reaction (Stevens-Johnson syndrome/toxic epidermal necrolysis) may happen. It can cause severe health problems that may not go away, and sometimes death. Get medical help right away if your child has signs like red, swollen, blistered, or peeling skin (with or without fever); red or irritated eyes; or sores in the mouth, throat, nose, or eyes.
• A severe and sometimes deadly effect has happened in people taking drugs for seizures like this drug. Call the doctor right away if your child has swollen glands; fever; rash; painful sores in the mouth or around the eyes; chest pain; signs of kidney problems like not able to pass urine or change in how much urine is passed; or signs of liver problems like dark urine, tiredness, decreased appetite, upset stomach or stomach pain, light-colored stools, throwing up, or yellow skin or eyes.
• Like other drugs that may be used for seizures, this drug may rarely raise the risk of suicidal thoughts or actions. The risk may be higher in people who have had suicidal thoughts or actions in the past. Call the doctor right away about any new or worse signs like depression; feeling nervous, restless, or grouchy; panic attacks; or other changes in mood or behavior. Call the doctor right away if any suicidal thoughts or actions occur.

Injection (if given in the vein):

• Some health problems may happen when this drug is given too fast. This includes trouble breathing or signs of high or low blood pressure like very bad headache or dizziness, passing out, or change in eyesight. Tell the doctor right away if your child has any of these signs.
• This drug may cause tissue damage if the drug leaks from the vein. Tell your child’s nurse if your child has any redness, burning, pain, swelling, blisters, skin sores, or leaking of fluid where the drug is going into your child’s body.

What are some other side effects of this drug?

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your child’s doctor or get medical help if any of these side effects or any other side effects bother your child or do not go away:

All products:

• Feeling dizzy or sleepy.
• Headache.
• Upset stomach or throwing up.
• Constipation.
• Feeling nervous and excitable.
• Trouble sleeping.

Injection:

• Irritation where the shot is given.

These are not all of the side effects that may occur. If you have questions about side effects, call your child’s doctor. Call your child’s doctor for medical advice about side effects.

You may report side effects to your national health agency.

How is this drug best given?

Give this drug as ordered by your child’s doctor. Read all information given to you. Follow all instructions closely.

All oral products:

• Give this drug with or without food. Give with food if it causes an upset stomach.

Liquid:

• Measure liquid doses carefully. Use the measuring device that comes with this drug. If there is none, ask the pharmacist for a device to measure this drug.

Injection:

• It is given as a shot into a muscle or vein.

What do I do if my child misses a dose?

All oral products:

• Give a missed dose as soon as you think about it.
• If it is close to the time for your child’s next dose, skip the missed dose and go back to your child’s normal time.
• Do not give 2 doses at the same time or extra doses.

Injection:

• Call your child’s doctor to find out what to do.

How do I store and/or throw out this drug?

All oral products:

• Store at room temperature protected from light. Store in a dry place. Do not store in a bathroom.
• Keep lid tightly closed.

Injection:

• If you need to store this drug at home, talk with your child’s doctor, nurse, or pharmacist about how to store it.

All products:

• Store this drug in a safe place where children cannot see or reach it, and where other people cannot get to it. A locked box or area may help keep this drug safe. Keep all drugs away from pets.
• Throw away unused or expired drugs. Do not flush down a toilet or pour down a drain unless you are told to do so. Check with your pharmacist if you have questions about the best way to throw out drugs. There may be drug take-back programs in your area.

General drug facts

• If your child’s symptoms or health problems do not get better or if they become worse, call your child’s doctor.
• Do not share your child’s drug with others and do not give anyone else’s drug to your child.
• Some drugs may have another patient information leaflet. If you have any questions about this drug, please talk with your child’s doctor, nurse, pharmacist, or other health care provider.
• If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.

Consumer Information Use and Disclaimer

This generalized information is a limited summary of diagnosis, treatment, and/or medication information. It is not meant to be comprehensive and should be used as a tool to help the user understand and/or assess potential diagnostic and treatment options. It does NOT include all information about conditions, treatments, medications, side effects, or risks that may apply to a specific patient. It is not intended to be medical advice or a substitute for the medical advice, diagnosis, or treatment of a health care provider based on the health care provider’s examination and assessment of a patient’s specific and unique circumstances. Patients must speak with a health care provider for complete information about their health, medical questions, and treatment options, including any risks or benefits regarding use of medications. This information does not endorse any treatments or medications as safe, effective, or approved for treating a specific patient. UpToDate, Inc. and its affiliates disclaim any warranty or liability relating to this information or the use thereof. The use of this information is governed by the Terms of Use, available at https://www.wolterskluwer.com/en/know/clinical-effectiveness-terms.

Last Reviewed Date

2024-11-11

Copyright

© 2024 UpToDate, Inc. and its affiliates and/or licensors. All rights reserved.