Phenobarbital
Commercial names and formulations:
Brand name: Luminal sodium
Formulations: Tablets, Elixir (liquid), and for Injection
Years on the market:
In the US since 1912
How to store it?
Store at room temperature
What does the body do to the medication?
Can I take it with food?
Yes
How long does it take to get to the blood after I take it?
30 minutes by mouth
How long does it take to start having a steady effect?
1-6 hours by mouth
Can this medication be started at a high dose or it has to be started gradually?
Gradually
How long does it stay in the body?
About 1 ½ days
How is it eliminated?
Liver
What does the medication do to the body?
Type of epilepsy that helps:
Partial Epilepsy
FDA approved for:
Generalized or partial seizures
Common side effects:
• Skin: scaling of the skin
• Bones: osteoporosis (painless softening of the bones) over the longterm
• Blood: anemia
• Liver: none
• Kidneys: none
• Stomach and intestines: nausea, vomiting
• Heart: none
• Brain: sedation, drowsiness, tiredness, dizziness, headache
• Mood: changes in emotions, phobias, excitement, delirium
• Others: shallow breathing
Serious side effects:
Dependence
Risk of suicidal thoughts or behavior
What happens if I get too much of it (intoxication)?
Symptoms may include slow or shallow breathing, decrease in blood pressure, possible coma, and death
What happens if I stop it suddenly (withdrawal)?
Phenobarbital should be stopped gradually. Some patients may experience withdrawal symptoms such as anxiety, tremor, weakness, and increase in seizures.
Who should not take this medication?
You should not take Phenobarbital if you are allergic to a class of drug called barbiturates or if you have liver problems or respiratory disease without a physician’s advice. Patients with acute intermittent porphyria should not use this medication.
What is the average dose and how many times a day should be given?
Children: 4-8 mg/kg/day (in divided doses). Dose may be adjusted based on blood levels
Adults: 60 mg/day (increased gradually to target dose of 90-120 mg/day) or higher based on blood levels
Does the body get used to the medication?
Yes
Medications to be careful with:
Other AEDs that may increase the blood level of Phenobarbital:
Phenytoin, Valproic Acid, Felbamate, Oxcarbazepine
Other AEDs that may decrease the blood level of Phenobarbital:
None anticipated
Other drug interactions:
Phenobarbital will lower levels of felbamate, carbamazepine, lamotrigine, topiramate, tiagabine, zonisamide, lorazepam, and diazepam, and valproic acid.
Phenobarbital lowers levels of estrogen, steroids, warfarin. Chloramphenicol, folate, and pyridoxine decreases levels of Phenobarbital.
Blood work required?
CBC and CPM?
Yes
How often?
One to three months initially, then yearly thefeafter
Normal range
10-30 mcg/mL
Women’s health
Affects contraceptives?
Yes. Lowers efficacy of oral contraceptives
Affect fertility?
This class of medication has been linked to infertility
Are safe in pregnancy?
Discuss with your doctor, Phenobarbital has been linked to birth defects.
Category
Pregnancy Category D
Can breastfeed?
Phenobarbital is passed through breast milk so it may or may not be safe to breast feed while taking Phenobarbital. The multiple benefits of breastfeeding need to be weighed against the probable small, but unknown, risks of the baby getting some limited amount of the medication. The baby needs to be watched closely for excessive sleepiness and poor feeding.
Affect bones (osteoporosis)?
Yes
Men’s health
Affects sexual performance?
Yes, this medication has been linked to impotence rarely
Affects fertility?
Yes, this medication is associated with lower sperm counts
Use other than epilepsy:
Sedative to relieve anxiety. Not commonly used.
Short-term treatment for insomnia. Not commonly used.