Information on Tablets A-Z
Why is this drug prescribed: Phenobarbital, a barbiturate, is used as a sleep aid and in the treatment of certain types of epilepsy, including generalized or grand mal seizures and partial seizures.
Most important fact about this drug: Phenobarbital can be habit-forming. You may become tolerant (needing more and more of the drug to achieve the same effect) and physically and psychologically dependent with continued use. Never increase the amount of phenobarbital you take without checking with your doctor.
How should you take this medication: Take this medication exactly as prescribed. If you are taking phenobarbital for seizures, do not discontinue it abruptly. --If you miss a dose... Take it as soon as you remember. If it is almost time for your next dose, skip the one you missed and go back to your regular schedule. Never take 2 doses at once. --Storage instructions... Store at room temperature in a tightly closed container.
What side effects may occur: Side effects cannot be anticipated. If any develop or change in intensity, notify your doctor as soon as possible. Only your doctor can determine whether it is safe for you to continue taking phenobarbital. Side effects may include: Abnormal thinking, aggravation of existing emotional disturbances and phobias, agitation, anemia, angioedema (swelling of face around lips, tongue, and throat, swollen arms and legs, difficulty breathing), allergic reactions (localized swelling, especially of the eyelids, cheeks, or lips, skin redness and inflammation), anxiety, confusion, constipation, decreased breathing, delirium, difficulty sleeping, dizziness, drowsiness, excitement, fainting, fever, hallucinations, headache, increased physical activity and muscle movement, irritability and hyperactivity in children, lack of muscle coordination, low blood pressure, muscle, nerve, or joint pain, especially in people with insomnia, nausea, nervousness, nightmares, psychiatric disturbances, rash, residual drowsiness, restlessness, excitement, and delirium when taken for pain, shallow breathing, sleepiness, slow heartbeat, slowdown of the nervous system, sluggishness, softening of bones, temporary cessation of breathing, vertigo, vomiting
Why should this drug not be prescribed: Phenobarbital should not be used if you suffer from porphyria (an inherited metabolic disorder), liver disease, or a lung disease that causes blockages or breathing difficulties, or if you have ever had an allergic reaction to or are sensitive to phenobarbital or other barbiturates.
Special warnings about this medication: Remember that phenobarbital may be habit-forming. Make sure you take the medication exactly as prescribed. Phenobarbital should be used with extreme caution, or not at all, by people who are depressed, or have a history of drug abuse. Be sure to tell your doctor if you are in pain, or if you have constant pain, before you take phenobarbital. Phenobarbital may cause excitement, depression, or confusion in elderly or weakened individuals, and excitement in children. If you have been diagnosed with liver disease or your adrenal glands are not functioning properly, make sure the doctor knows about it. Phenobarbital should be prescribed with caution. Barbiturates such as phenobarbital may cause you to become tired or less alert. Be careful driving, operating machinery, or doing any activity that requires full mental alertness until you know how you react to this medication.
Possible food and drug interactions when taking this medication: Phenobarbital may increase the effects of alcohol. Avoid alcoholic beverages while taking phenobarbital. If phenobarbital is taken with certain other drugs, the effects of either could be increased, decreased, or altered. It is especially important to check with your doctor before combining phenobarbital with the following: Antidepressant drugs known as MAO inhibitors, including Nardil and Parnate Antihistamines such as Benadryl Blood-thinning medications such as Coumadin Doxycycline (Doryx, Vibramycin) Griseofulvin (Fulvicin-P/G, Grifulvin V) Narcotic pain relievers such as Percocet Oral contraceptives Other epilepsy drugs such as Dilantin, Depakene, and Depakote Other sedatives such as Nembutal and Seconal Steroids such as Medrol and Deltasone Tranquilizers such as Xanax and Valium
Special information if you are pregnant or breastfeeding: Barbiturates such as phenobarbital may cause damage to the developing baby during pregnancy. Withdrawal symptoms may occur in an infant whose mother took barbiturates during the last 3 months of pregnancy. If you are pregnant or plan to become pregnant, inform your doctor immediately. Phenobarbital appears in breast milk and could affect a nursing infant. If phenobarbital is essential to your health, your doctor may advise you to stop breastfeeding until your treatment is finished.
Recommended dosage: ADULTS: Sedation The usual initial dose of phenobarbital is a single dose of 30 to 120 milligrams. Your doctor may repeat this dose at intervals, depending on how you respond to this medication. You should not take more than 400 milligrams during a 24-hour period. Daytime Sedation The usual dose is 30 to 120 milligrams a day, divided into 2 to 3 doses. To Induce Sleep The usual dose is 100 to 200 milligrams. Anticonvulsant Use Phenobarbital dosage must be individualized on the basis of specific laboratory tests. Your doctor will determine the exact dose best for you. The usual dose is 60 to 200 milligrams daily. CHILDREN: Anticonvulsant Use The phenobarbital dosage must be individualized on the basis of specific laboratory tests. Your doctor will determine the exact dose best for your child. The usual dose is 3 to 6 milligrams per 2.2 pounds of body weight per day. OLDER ADULTS: If you are old or debilitated, your dose may be lower than the regular adult dose. People who have liver or kidney disease may also require a lower dose of phenobarbital.
Overdosage: Barbiturate overdose can be fatal. If you suspect an overdose, seek medical treatment immediately. Symptoms of phenobarbital overdose may include: Congestive heart failure, diminished breathing, extremely low body temperature, fluid in lungs, involuntary eyeball movements, irregular heartbeat, kidney failure, lack of muscle coordination, low blood pressure, poor reflexes, skin reddening or bloody blisters, slowdown of the central nervous system