Generic Name: phenobarbital (fee-noe-BAR-bih-tal)
Brand Name: Generic only. No brands available.
Phenobarbital tablets are used for:
Treating and preventing seizures, and treating sleep disorders. It may also be used for other conditions as determined by your doctor.
Phenobarbital tablets are a barbiturate. It works by depressing the central nervous system or brain. In low doses, it causes mild sedation. As the dose increases, it can cause sleep and even coma. As it causes the brain to relax, it also decreases seizure activity.
Do NOT use phenobarbital tablets if:
- you are allergic to any ingredient in phenobarbital tablets
- you have a history of the blood disorder porphyria
- you are taking methoxyflurane, sodium oxybate (GHB), or voriconazole
- you consume alcohol
- you have liver problems or lung disease with breathing problems
Contact your doctor or health care provider right away if any of these apply to you.
Before using phenobarbital tablets:
Some medical conditions may interact with phenobarbital tablets. 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 have depression, pain, breathing problems, suicidal tendencies, or are in shock
- if you have a history of substance abuse or dependence
Some MEDICINES MAY INTERACT with phenobarbital tablets. Tell your health care provider if you are taking any other medicines, especially any of the following:
- Ethanol, MAO inhibitors (eg, phenelzine), quinine, sodium oxybate (GHB), stiripentol, or valproic acid because side effects such as increased sedation and difficulty breathing may occur
- Ethanol, methoxyflurane, orsodium oxybate because the risk of their side effects may be increased by phenobarbital tablets
- Anticoagulants (eg, warfarin), beta-blockers (eg, propranolol), clozapine, corticosteroids (eg, hydrocortisone), cyclosporine, doxorubicin, doxycycline, estrogens (eg, estradiol), imatinib, metronidazole, steroidal contraceptives (eg, birth control pills), theophylline, or voriconazolebecause their effectiveness may be decreased by phenobarbital tablets.
This may not be a complete list of all interactions that may occur. Ask your health care provider if phenobarbital tablets 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.
How to use phenobarbital tablets:
Use phenobarbital tablets as directed by your doctor. Check the label on the medicine for exact dosing instructions.
- Take phenobarbital tablets by mouth with or without food.
- Do not suddenly stop taking phenobarbital tablets or change the dose without checking with your doctor.
- If you miss a dose of phenobarbital tablets, take it as soon as possible. If it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not take 2 doses at once.
Ask your health care provider any questions you may have about how to use phenobarbital tablets.
Important safety information:
- Phenobarbital tablets may cause dizziness, drowsiness, or lightheadedness. These effects may be worse if you take it with alcohol or certain medicines. Use phenobarbital tablets with caution. Do not drive or perform other possibly unsafe tasks until you know how you react to it.
- Do not drink alcohol or use medicines that may cause drowsiness (eg, sleep aids, muscle relaxers) while you are using phenobarbital tablets; it may add to their effects. Ask your pharmacist if you have questions about which medicines may cause drowsiness.
- Use phenobarbital tablets with caution in the ELDERLY; they may be more sensitive to its effects.
- Phenobarbital tablets should not be used in CHILDREN younger than 12 years old; safety and effectiveness in these children have not been confirmed.
- Hormonal birth control (eg, birth control pills) may not work as well while you are using phenobarbital tablets. To prevent pregnancy, use an extra form of birth control (eg, condoms).
- PREGNANCY and BREAST-FEEDING: Phenobarbital tablets has been shown to cause harm to the fetus. If you think you may be pregnant, contact your doctor. You will need to discuss the benefits and risks of using phenobarbital tablets while you are pregnant. Phenobarbital tablets are found in breast milk. If you are or will be breast-feeding while you use phenobarbital tablets, check with your doctor. Discuss any possible risks to your baby.
When used for long periods of time or at high doses, phenobarbital tablets may not work as well and may require higher doses to obtain the same effect as when originally taken. This is known as TOLERANCE. Talk with your doctor if phenobarbital tablets stops working well. Do not take more than prescribed.
Some people who use phenobarbital tablets for a long time may develop a need to continue taking it. People who take high doses are also at risk. This is known as DEPENDENCE or addiction. If you stop taking phenobarbital tablets suddenly, you may have WITHDRAWAL symptoms. These may include anxiety, nausea, sleeplessness, and body aches.
Possible side effects of phenobarbital tablets:
All medicines may cause side effects, but many people have no, or minor side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome:
Seek medical attention right away if any of these SEVERE side effects occur:
Clumsiness; dizziness; drowsiness; excessive daytime drowsiness ("hangover effect"); feeling of a whirling motion; headache; lightheadedness; nausea; tired feeling; vomiting; weak bones.
Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); confusion; difficulty sleeping; fainting; intense pain; very slow breathing.
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. Call your doctor for medical advice about side effects. To report side effects to the appropriate agency, please read the Guide to Reporting Problems to FDA.
If OVERDOSE is suspected:
Contact 1-800-222-1222 (the American Association of Poison Control Centers), your local poison control center, or emergency room immediately. Symptoms may include cold, clammy skin; change in size of pupil; deep sleep; loss of consciousness; slowed or fast breathing.Proper storage of phenobarbital tablets:
Store phenobarbital tablets at room temperature (59 to 86 degrees F; 15 to 30 degrees C) in a tightly closed container. Store away from heat, moisture, and light. Do not store in the bathroom. Keep phenobarbital tablets out of the reach of children and away from pets.
- If you have any questions about phenobarbital tablets, please talk with your doctor, pharmacist, or other health care provider.
- Phenobarbital tablets are to be used only by the patient for whom it is prescribed. Do not share it with other people.
- If your symptoms do not improve or if they become worse, check with your doctor.
- Check with your pharmacist about how to dispose of unused medicine.
This information should not be used to decide whether or not to take phenobarbital tablets or any other medicine. Only your health care provider has the knowledge and training to decide which medicines are right for you. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about phenobarbital tablets. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to phenobarbital tablets. This information is not specific medical advice and does not replace information you receive from your health care provider. You must talk with your healthcare provider for complete information about the risks and benefits of using phenobarbital tablets.
Disclaimer: This information should not be used to decide whether or not to take this medicine or any other medicine. Only your health care provider has the knowledge and training to decide which medicines are right for you. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about this medicine. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this medicine. This information is not specific medical advice and does not replace information you receive from your health care provider. You must talk with your healthcare provider for complete information about the risks and benefits of using this medicine.