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What is phenobarbital?
Phenobarbital is in a group of drugs called barbiturates (bar-BIT-chur-ates). Phenobarbital slows the activity of your brain and nervous system. Phenobarbital is used to treat or prevent seizures. It is also used short-term to treat insomnia, or as a sedative before surgery. Phenobarbital may also be used for other purposes not listed in this medication guide.

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What is the price of this medication and similar alternatives?

This pricing information is subject to change at the sole discretion of DS Pharmacy. For the most current and up-to-date pricing information, please visit drugstore.com.

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What are the possible side effects of phenobarbital?

Phenobarbital may cause a severe allergic reaction. Stop taking phenobarbital and get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have any of these serious side effects:

• restless muscle movements in your eyes, tongue, jaw, or neck;

• slow heartbeat, shallow breathing;

• feeling light-headed, fainting;

• a fever or a sore throat;

• sores in your mouth;

• easy bruising or bleeding; or

• broken blood vessels under your skin.

Less serious side effects may include:

• drowsiness or dizziness;

• problems with memory or concentration;

• excitement, irritability, aggression, or confusion (especially in children or older adults);

• loss of balance or coordination;

• nausea, constipation;

• headache; or

• "hangover" effect (drowsiness the day after a dose).

This is not a complete list of side effects and others may occur. Tell your doctor about any unusual or bothersome side effect.

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How should I take phenobarbital?
Take this medication exactly as it was prescribed for you. Do not take the medication in larger amounts, or take it for longer than recommended by your doctor. Follow the directions on your prescription label. Take phenobarbital only when you are getting ready for several hours of sleep. You may fall asleep very quickly after taking the medicine. Take this medicine with a full glass of water. Measure the liquid form of phenobarbital with a special dose-measuring spoon or cup, not a regular table spoon. If you do not have a dose-measuring device, ask your pharmacist for one.

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What is the most important information I should know about phenobarbital?
Phenobarbital may cause a severe allergic reaction. Stop taking phenobarbital and get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat. Do not stop using phenobarbital without first talking to your doctor, even if you feel better. You may have increased seizures if you stop using phenobarbital suddenly. You will need to use less and less before you stop the medication completely.

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What happens if I miss a dose?
Take the missed dose as soon as you remember. If it is almost time for your next dose, skip the missed dose and take the medicine at your next regularly scheduled time. Do not take extra medicine to make up the missed dose.

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What other drugs will affect phenobarbital?
Before taking phenobarbital, tell your doctor if you are using any of the following drugs: doxycycline (Adoxa, Doryx, Mondox, Oracea, Vibramycin, and others); other seizure medications such as divalproex (Depakote), phenytoin (Dilantin), or valproic acid (Depakene); an MAO inhibitor such as isocarboxazid (Marplan), phenelzine (Nardil), rasagiline (Azilect), selegiline (Eldepryl, Emsam), or tranylcypromine (Parnate); griseofulvin (Grisactin, Fulvicin PG, Grifulvin V); birth control pills or estrogen hormone replacement, including estrogen (Premarin), estradiol (Estrace, Femtrace, and others), progesterone (Progest, Prometrium), and others;

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Can I take this if I am pregnant or trying to get pregnant or if I am breastfeeding?

Phenobarbital has been assigned to pregnancy category D by the FDA. An increased risk of congenital malformations has been associated with use of anticonvulsants agents (including phenobarbital) during pregnancy. Anomalies associated with anticonvulsant use in pregnancy include neural tube defects, cleft lips, cleft palates, cardiac defects, and microcephaly. Neonatal barbiturate withdrawal symptoms have also been reported in infants whose mothers took phenobarbital during pregnancy. There are no controlled data in human pregnancy. Phenobarbital should only be given during pregnancy when there are no alternatives and benefit outweighs risk.

Phenobarbital exposure in utero has been reported to potentially have long term deleterious effects on cognitive performance. A recent prospective case control cohort study of pregnant women with epilepsy has reported that phenobarbital, phenytoin, and carbamazepine are all associated with an increased risk of fetal death and anomalies. In addition, of these three antiepileptic medications, phenobarbital was associated with the poorest pregnancy outcome in terms of fetal death and anomalies. Physicians are encouraged to register patients before fetal outcome is known (e.g., ultrasound, results of amniocentesis, etc) into the Antiepileptic Drug (AED) Pregnancy Registry at 1-888-233-2334 or 1-888-AED-AED4. This is an ongoing study at the Massachusetts General Hospital/Harvard Medical School. This study is designed to monitor the outcomes of pregnant women exposed to antiepileptic drugs in order to determine which therapies are associated with increased risk.

Phenobarbital is excreted into human milk in small amounts. However, because of the prolonged half-life of the drug in neonates, accumulation of phenobarbital may occur and neonatal serum levels can potentially exceed maternal serum levels. Sedation and lethargy have been reported in nursing infants. The American Academy of Pediatrics classifies phenobarbital as a drug which has "caused significant effects in some nursing infants and should be given to nursing mothers with caution". Some investigators have recommended close monitoring of infant blood concentrations if a nursing mother must take phenobarbital.

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Who should NOT use this medication?

• Known hypersensitivity to any barbiturates.
• Respiratory disease in which dyspnea or obstruction is evident.
• Marked impairment of hepatic function.
• History of manifest or latent porphyria (due to potential for exacerbation of acute intermittent porphyria or porphyria variegata).
• Previous addiction to sedative and/or hypnotic drugs.

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What happens if I overdose?
Seek emergency medical attention if you think you have used too much of this medicine. An overdose of phenobarbital can be fatal. Overdose symptoms may include slow or shallow breathing, blurred vision, extreme drowsiness, urinating less than usual or not at all, feeling light-headed, or fainting.

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What should I discuss with my healthcare provider before taking phenobarbital?
Some people using this medicine have engaged in activity such as driving, eating, or making phone calls and later having no memory of the activity. If this happens to you, stop taking phenobarbital and talk with your doctor about another treatment for your sleep disorder. Do not take this medication if you are allergic to phenobarbital, or if you have porphyria. Before taking phenobarbital, tell your doctor if you are allergic to any drugs, or if you have: severe asthma, chronic obstructive pulmonary disorder (COPD), or other breathing disorder;

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Can I stop taking the medication if I feel better?
As a general rule, you should always take your medications exactly as prescribed and do not change the dosage or stop taking the medication without first discussing it with your healthcare provider.

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I am on so many medications; do I have to take them all?
This is called polypharmacy—many different medications being used at the same time by one person. Sometimes, being on multiple medications is acceptable and appropriate but at other times it may be problematic. If you are receiving your medications from multiple physicians you need to ensure that they all know what medications you are taking. The best way to do this is to make a list of all the medications you are currently using, including all nutritional supplements, homeopathic remedies, vitamins and over-the-counter drugs (if possible, also include all the diseases you have been diagnosed with). Give a copy to every doctor who takes care of you so they have it on file, this way they can avoid duplicating medications and perhaps even try to consolidate some. After every doctor's visit remember to update the list accordingly. Also, as much as you possibly can, try to use the same pharmacy to fill all your prescriptions, this way any potential drug interactions can be caught and averted.

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Where can I get more information?
More Information

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