Phenobarbital (fee-noe-bar-bih-tal) is a generic medication manufactured by several companies. It is the oldest epilepsy medicine still in use. In 1912, two independent teams of chemists created the drug under the name of Luminal.

Phenobarbital is a barbiturate, a class of medicines used to bring on sedation or sleepiness. This can be a disadvantage, along with behavioral changes and the risk of withdrawal seizures.

The advantages of phenobarbital are its long history of use, low cost, and effectiveness. It has a long half-life, which keeps the level of medication in the blood relatively stable over the course of the day even when it is taken in only one daily dose (often at bedtime).

Forms of Phenobarbital
Phenobarbital is available in several forms. The name or appearance may differ from country to country, or even from manufacturer to manufacturer, but usually the dose will be the same. In the United States, several companies sell generic phenobarbital, in these forms:

Tablets

		15-mg
		30-mg
		60-mg
		100-mg

Elixir (liquid): 20 mg per 5 mL (milliliters)
Phenobarbital sodium for injection

How to take and store Phenobarbital
Phenobarbital can be taken either with food or without food, but patients should be consistent each day in whether they take it with food or not.

Phenobarbital is usually taken just once a day. Most people find that sleepiness is less of a problem if they take the phenobarbital 30 to 60 minutes before bedtime.

If needed, tablets may be crushed and put in foods for children. A liquid (elixir) is available for those who cannot swallow pills, however. This liquid can be given with water, milk, or juice. Patients should use the same standard-size medicine spoon or dropper each time to get an accurate dose.

Patients should be cautioned if you write a new prescription using a different strength of phenobarbital. For example, if you've been prescribing 30-mg tablets and the new prescription is for 60-mg tablets, advise the patient about how many phenobarbital tablets should now be taken.

Phenobarbital should be stored at room temperature, away from heat, direct light, and dampness. The liquid form should be prevented from freezing. Advise patients to keep phenobarbital out of the reach of children, since overdose is especially dangerous in children.

Don't use more than the doctor prescribes. If one or two extra tablets or an extra spoonful of liquid are taken, call the doctor for advice. For a larger overdose, call your local poison control center or emergency room right away unless you have other specific directions from your doctor.

Missed Doses
Missed doses of phenobarbital should be taken right away unless it is almost time for the next dose. In that case, patients should skip the forgotten dose (rather than taking a double dose) or call for further instructions.

Patients who often forget doses may benefit from using a special pillbox or watch with an alarm.