Phenobarbital oral tablet dosage: A detailed guide

This article describes phenobarbital oral tablet’s dosages and strengths and gives details on how to take it. You’ll also find information on cost savings and coupon options for phenobarbital. If you want to know more about phenobarbital oral tablet, see this overview article. It covers details about the drug’s uses and side effects, ways to save on cost, and more.

Phenobarbital oral tablet is a generic medication. It’s not available in a brand-name version. Phenobarbital also comes as an oral elixir and an injectable, but these forms aren’t described in this article. To learn more about other forms of phenobarbital, talk with your doctor.

Note: The Food and Drug Administration (FDA) has not approved phenobarbital. This is because the drug has been available since before the FDA began its drug approval process. If you have questions about this, talk with your doctor or pharmacist.

Boxed warnings

This drug has boxed warnings about the risk of serious effects if taken with opioids, the risks of misuse and addiction, and the risks of dependence and withdrawal. A boxed warning is the most serious warning from the Food and Drug Administration (FDA).

For more information about the risks of dependence and withdrawal, see the “Withdrawal from phenobarbital” section below. See the end of this article for more information about the other boxed warnings.

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Form and strengths of phenobarbital

Phenobarbital oral tablet comes as follows:

• Form: tablet that you swallow
• Strengths: 15 milligrams (mg), 16.2 mg, 30 mg, 32.4 mg, 60 mg, 64.8 mg, 97.2 mg, 100 mg

Dosage of phenobarbital

This article describes the recommended dosages for phenobarbital oral tablet. The drugmaker provides these dosages.

If your doctor prescribes this medication, you should follow the dosage they prescribe. Your doctor will determine the dosage that best meets your needs. Do not change your dosage of phenobarbital oral tablet without your doctor’s recommendation.

Usual recommended dosages of phenobarbital in adults

Doctors will prescribe a dosage of phenobarbital based on the condition being treated.

The following table shows the recommended dosages of phenobarbital in milligrams (mg).

Dosage of phenobarbital in children

The recommended dosage of phenobarbital for seizures in children in milligrams per kilogram (mg/kg) of body weight is 3–6 mg/kg per day.

Dosage adjustments for phenobarbital

Your doctor will prescribe a dosage of phenobarbital oral tablet based on several factors. These include:

• the specific condition being treated and how severe it is
• your age
• other health conditions you may have

Missed dose of phenobarbital

Talk with your doctor or pharmacist right away if you realize you forgot to take a dose of phenobarbital oral tablet. They may advise you to take the missed dose. Or they may advise you to skip it and take your next dose as scheduled.

For tips on how to plan your doses of phenobarbital oral tablet and avoid missing a dose, read this article. You could also try:

• downloading a reminder app on your phone
• setting an alarm
• putting a note where you’ll see it, such as on your calendar, bathroom mirror, or bedside table

Frequently asked questions

Below are answers to some commonly asked questions about phenobarbital oral tablet and its dosage.

How long does it take phenobarbital to start working?

Phenobarbital usually starts to work about 1 hour after your dose.

If you have more questions about this, talk with your doctor.

Is phenobarbital taken long term?

Sometimes. Doctors may prescribe phenobarbital oral tablet as a short-term or long-term treatment. If you and your doctor decide that it’s safe and effective for your condition, you may take it long term.

If you have questions about how long you should take phenobarbital oral tablet, talk with your doctor.

Withdrawal from phenobarbital

Phenobarbital has a boxed warning about the risks of dependence and withdrawal. A boxed warning is the most serious warning from the Food and Drug Administration (FDA).

Taking phenobarbital for a long time can cause drug dependence. With dependence, your body needs the drug to function as usual. Withdrawal symptoms may occur if you stop taking the drug. Withdrawal symptoms are side effects that can occur when you stop taking a drug that your body has become dependent on. Examples include anxiety, difficulty sleeping, delirium, and seizures. In severe cases, withdrawal symptoms can cause death.

Due to these risks, you should not stop taking phenobarbital without talking with your doctor first. They will likely come up with a plan to gradually lower your dosage until it’s safe for you to stop the medication completely.

How phenobarbital is taken

You’ll swallow phenobarbital oral tablet as prescribed by your doctor. You can take it with or without food.

Your doctor may advise that you take this medication around the same time each day. This helps keep a consistent amount of the drug in your body. And that can help the drug work more effectively.

Phenobarbital oral tablets are scored, meaning they can be cut in half along the score line (groove) if needed. Otherwise, the drugmaker hasn’t specified whether the tablets can but chewed or crushed. Swallow them whole. If it’s hard for you to swallow tablets, view this article. It provides suggestions on how to swallow medications that come in pill form.

Also, be sure to talk with your doctor or pharmacist if you’re having difficulty taking your medication. They can offer recommendations about taking it.

Phenobarbital coupon

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Overdose of phenobarbital

It’s important that you do not take more phenobarbital oral tablet than your doctor prescribes. Doing so can lead to harmful effects.

Symptoms of phenobarbital overdose

Symptoms of an overdose can include:

• problems with balance
• erratic eye movements, which is known as nystagmus
• slowed or shallow breathing, which is known as respiratory depression
• low body temperature
• low blood pressure
• pulmonary edema (when your lungs fill with fluid)
• cardiac arrest (when your heart stops beating)

What to do if you take too much phenobarbital

If you think you’ve taken too much phenobarbital, call your doctor or pharmacist right away. Or you could call 800-222-1222 to speak with someone at America’s Poison Centers. You can also use its online resource. If you have severe symptoms, call 911 or a local emergency number immediately. You can also go to the closest emergency room.

What to ask your doctor

This article describes the usual recommended dosages for phenobarbital oral tablet. If your doctor prescribes this medication, they’ll determine the dosage that’s best for you.

Do not change your dosage of phenobarbital oral tablet without your doctor’s recommendation. You should take phenobarbital oral tablet exactly as your doctor prescribes it. Let your doctor know if you have concerns or questions about your treatment plan.

Here’s a list of some possible questions you may want to ask your doctor:

• How long will I need to take phenobarbital?
• Will you be changing my dosage of phenobarbital if I take other drugs with it?
• Will a higher dosage of phenobarbital increase my risk of side effects?

Boxed warnings for phenobarbital

This drug has boxed warnings about the risk of serious effects if taken with opioids, the risks of misuse and addiction, and the risks of dependence and withdrawal. A boxed warning is the most serious warning from the Food and Drug Administration (FDA).

Risk of serious effects if taken with opioids: Taking phenobarbital with opioid drugs can cause serious side effects. Examples of opioids include oxycodone (Roxicodone) and fentanyl (Fentora, Actiq). These serious side effects include slow or shallow breathing, extreme sleepiness, coma, and death.

Due to this risk, doctors typically won’t prescribe phenobarbital if you’re taking an opioid unless it’s the best or the only treatment option. If you’re taking these medications together, call 911 or get emergency medical help right away if you develop severe side effects. These include:

• difficulty breathing
• difficulty waking up or severe sleepiness

Risks of misuse and addiction: Phenobarbital has risks of misuse and addiction. Misuse means a drug is taken in a way other than how it’s prescribed. Addiction refers to feeling unable to stop using a drug, even though it may be causing harm.

Due to these risks, phenobarbital is a schedule IV controlled substance in the United States. Controlled substances have restrictions on how they can be prescribed and dispensed at pharmacies in order to lower the risk of misuse and addiction.

Risks of dependence and withdrawal: For more information about the risks of dependence and withdrawal, see the “Withdrawal from phenobarbital” section above.

To learn more about these boxed warnings for phenobarbital, you can talk with your doctor.

Disclaimer: Optum Perks has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.