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Phenobarbital Coupon - Phenobarbital 64.8mg tablet

phenobarbital

Generic Luminal
Used for Epilepsy, Sedation

Phenobarbital treats seizures and is used as a sedative medication. It's a part of the barbiturate drug class. The most common side effect is sleepiness. It's a schedule IV controlled substance due to the risk of dependence. This means if you suddenly stop the medication, you could get withdrawal symptoms like weakness, muscle twitching, or even confusion and disorientation. There are no brand names available anymore, so only generic versions exist.

Reviewed by:
reviewerRobert Chad Hakim, PharmD, BCCCP
reviewerKristianne Hannemann, PharmD
Last reviewed on July 24, 2023
basics-icon

What is Phenobarbital?

What is Phenobarbital used for?

How Phenobarbital works

Phenobarbital is a barbiturate. It works by slowing down brain activity. This is thought to help treat seizures.

Drug facts

Common BrandsLuminal(brand no longer available)
Drug ClassBarbiturate
Controlled Substance ClassificationSchedule IV
Generic StatusLower-cost generic available
AvailabilityPrescription only
warnings-icon

Risks and warnings for Phenobarbital

Phenobarbital can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.

Dependence and withdrawal

  • Risk factors: History of substance use disorder | History of mental health problems | Using higher doses of phenobarbital for a long time | Stopping phenobarbital suddenly

Phenobarbital carries a risk for dependence (when your body needs the medication to function normally). Take the medication exactly as prescribed. Don't change the dose or how often you take it without talking to your provider first. Misusing this medication can cause it to not work as well. It can also raise the risk for serious and possibly life-threatening side effects, such as dangerously slow breathing. If you need to stop taking phenobarbital, talk to your provider about a way to safely do so. Stopping the medication too suddenly can lead to life-threatening withdrawal symptoms, such as seizures and delirium.

Drowsiness

  • Risk factors: Taking high doses of phenobarbital | Drinking alcohol | Taking other medications that can cause sleepiness

Phenobarbital can cause extreme dizziness and sleepiness, which can lower your ability to think, react, and focus. Your risk might be higher if you're taking other medications that can cause you to feel sleepy (e.g., benzodiazepines or sleep medications). Make sure you know how this medication affects you before driving a car or doing activities that require your concentration. Talk to your healthcare provider right away if you feel too sleepy from taking phenobarbital.

Extreme excitement

  • Risk factors: History of short-term or long-term pain | Older age | Younger age | Extreme weakness

Phenobarbital can make certain people feel agitated, excited, or confused, rather than sleepy or calm, especially if you have short-term or long-term pain (e.g., cancer-related pain). Some older adults and children might also feel more excitement after taking the medication. Let your provider know if you experience this after taking phenobarbital.

Dangerously slow breathing (respiratory depression)

  • Risk factors: Taking medications that can cause slow breathing | Drinking alcohol | Older age | Medical conditions that cause breathing problems (e.g., COPD, asthma, head injury) | Taking too much phenobarbital

Phenobarbital can cause dangerously slow breathing, which can be life-threatening. Don't take phenobarbital with alcohol or other medications that slow your body down (e.g., benzodiazepines, opioids, or muscle relaxants). Doing so raises your risk of extremely slowed breathing. If you or your loved one notices that you have trouble breathing or have bluish-colored lips, fingers, or toes, call 911 to get medical help right away.

Harm to newborn babies

Phenobarbital can cause harm, including withdrawal symptoms like weakness or trouble sleeping, to babies when the medication is taken by pregnant mothers. Talk to your provider about the risks and benefits using phenobarbital while pregnant. There is a North American Antiepileptic Drug (NAAED) Pregnancy Registry to monitor the safety of anti-seizure medications during pregnancy. If you're currently pregnant and taking phenobarbital, it's encouraged that you enroll in the registry to help researchers learn more about the risks.

Small amounts of phenobarbital can get into breast milk. This could lead to drowsiness in babies who are breastfed by mothers taking this medication. If you're breastfeeding, speak to your provider about safe ways to feed your baby.

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Side effects of Phenobarbital

The following side effects may get better over time as your body gets used to the medication. Let your healthcare provider know immediately if you continue to experience these symptoms or if they worsen over time.

Common Side Effects

  • Sleepiness
  • Dizziness
  • Poor balance or coordination

Less Common Side Effects

  • Nausea
  • Vomiting
  • Constipation
  • Headache
  • Slowed heart rate
  • Fainting
  • Confusion

Phenobarbital serious side effects

Contact your healthcare provider immediately if you experience any of the following.

  • Dangerously slow breathing: shortness of breath, bluish-colored lips, fingers, or toes
  • Serious allergic and skin reactions: sore throat, fever, fatigue, rash, hives, painful blisters, skin reddening, skin peeling
When do Phenobarbital possible side effects begin and end?
Time passed since treatment started:
H
D
W
M
Risk of sleepiness
Risk of dizziness
Risk of confusion
If a line continues to the right, you'll likely keep experiencing this side effect once it starts.

Source: DailyMed

The following Phenobarbital side effects have also been reported

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

Rare

Confusion (especially in the elderly)

dizziness, lightheadedness that continues, or fainting

eye pain

skin rash or hives

Incidence not known

Cough

difficulty with swallowing

fast irregular, pounding, or racing heartbeat or pulse

fever

hives or welts

hoarseness

irritation

itching skin

joint pain, stiffness, or swelling

puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue

redness of the skin

shortness of breath

skin rash

tightness in the chest

trouble with breathing

wheezing

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

Constipation

decreased sweating

dryness of the mouth, nose, throat, or skin

Less common or rare

Bloated feeling

blurred vision

difficult urination

difficulty with swallowing

drowsiness

false sense of well-being

headache

increased sensitivity of eyes to light

loss of memory

nausea or vomiting

redness or other signs of irritation at the place of injection

trouble with sleeping

unusual tiredness or weakness

Incidence not known

Decreased interest in sexual intercourse

inability to have or keep an erection

loss in sexual ability, desire, drive, or performance

loss of taste

For patients using scopolamine:

After you stop using scopolamine, your body may need time to adjust. The length of time this takes depends on the amount of scopolamine you were using and how long you used it. During this period of time check with your doctor if you notice any of the following side effects:

Anxiety

irritability

nightmares

pupil of one eye is larger (patch only)

sensitivity of eyes to light (patch only)

trouble in sleeping

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

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pros-and-cons-icon

Pros and cons of Phenobarbital

Pros

  • Works to control seizures and as also as a sedative
  • Dose can be adjusted based on your response
  • Available in lower-cost, generic forms
  • Available as a tablet and liquid

Cons

  • Can lead to withdrawal effects if stopped too suddenly
  • Requires regular blood tests to check appropriate levels to determine the right dose
  • Carries a risk of dependence
  • Not safe during pregnancy
pharmacist-tips-icon

Pharmacist tips for Phenobarbital

pharmacist
  • You can take phenobarbital with or without food, but if it upsets your stomach, try taking it with food to help.
  • Make sure to mark your appointments in your calendar to see your provider and get any blood tests done while taking phenobarbital. Your provider will likely order different tests to make sure the medication is working well for you and you're not having side effects.
  • Phenobarbital can make you sleepy and dizzy. Don't drink alcohol, drive, or do anything that requires concentration until you know how this medication affects you.
  • Phenobarbital can interact with some commonly prescribed medications. Some medications that interact with include phenytoin (Dilantin), doxycycline, and warfarin (Coumadin). Make sure to tell your provider and pharmacist about all of the medications you're taking before starting phenobarbital.
  • Phenobarbital can cause hormonal birth control to not work as well, which can lead to unwanted pregnancies. Talk to your provider about which methods of birth control would be the best option and if you need to use a back-up method of protection while taking phenobarbital.
  • Don't change your dose or stop taking phenobarbital without talking to your provider first. Doing so can cause withdrawal symptoms like seizures, anxiety, and sleeping problems. Follow your provider's instructions to lower your dose slowly over a period of time to stop the medication completely.

Phenobarbital oral liquid

  • Make sure to use an oral syringe or medication dosing cup to measure out your phenobarbital liquid dose. Don't use household spoons because they aren't accurate and might cause you to take the wrong dose. Be sure to shake the bottle well before measuring the dose.
  • Store phenobarbital liquid at room temperature in the original bottle it came in from the pharmacy.
faq-icon

Common questions about Phenobarbital

Yes, phenobarbital is a schedule IV controlled substance. This is because it can be habit-forming with a risk of dependence. Dependence is when you rely on a medication to function normally and experience withdrawal symptoms (e.g., depression, weakness, vision changes) if you stop taking it suddenly. To help lower the risk for dependence, only take phenobarbital as prescribed by your provider. Follow your provider's instructions to slowly lower the dose before completely stopping the medication.

In adults, it takes on average about 16 days for most of phenobarbital to leave your body after a single dose. In children, it takes on average about 23 days. This time frame is estimated based on the half-life of phenobarbital. It can differ from person to person depending on other factors, such as your age and whether you have kidney or liver problems. If you're having side effects from phenobarbital, they might last up until the time it takes for the medication to clear out of your system.

If you miss a dose of phenobarbital, it puts you at higher risk for seizures. Try to set a reminder of when to take your doses throughout the day. If you forget to take your dose, take it as soon as you remember. But if it's almost time for your next dose, skip the missed dose and continue with your usual dosing schedule. Never double up to make up for missed doses, since this can lead to serious side effects.

No, phenobarbital isn't a narcotic because it's not an opioid pain medication. Phenobarbital is considered a barbiturate.

Yes, one of the most common side effects of phenobarbital is sleepiness. In fact, phenobarbital is used as a sedative to put people to sleep for surgeries or procedures. Before driving or performing activities where you need to be alert, wait and see how this medication affects you.

In general, phenobarbital starts to work within 1 hour and it typically lasts for 10 to 12 hours. But it can vary depending on your condition.

It's recommended that you avoid drinking alcohol while taking phenobarbital. Both alcohol and phenobarbital can make you feel sleepy and dizzy. So mixing alcohol with phenobarbital might make these effects worse. Also, alcohol can potentially make your seizures come back.

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Phenobarbital dosage

The average cost for 60 tablets of 64.8mg of Phenobarbital is $13.12 with a free GoodRx coupon. This is 71.10% off the average retail price of $45.40.
ml of elixirMl of elixir
DosageQuantityPrice as low asPrice per unit
20mg/5ml120 ml$12.20$0.10
tabletTablet
DosageQuantityPrice as low asPrice per unit
16.2mg60 tablets$8.75$0.15
32.4mg60 tablets$14.19$0.24
64.8mg60 tablets$13.12$0.22
97.2mg60 tablets$15.62$0.26
60mg60 tablets$10.24$0.17
100mg60 tablets$12.79$0.21
15mg60 tablets$8.12$0.14
30mg60 tablets$8.75$0.15

Typical dosage for Phenobarbital

The dose depends on your age, weight, and condition being treated. In general:

Sedation

  • Adults: The typical dose is 30 mg to 120 mg by mouth per day, split up into 2 or 3 doses throughout the day. If used before a procedure, your provider might give you 100 mg to 200 mg by mouth once.

Seizures

  • Adults: The typical dose is 60 mg to 200 mg by mouth per day.
  • Children: The typical dose is 3 mg/kg to 6 mg/kg of body weight by mouth per day.

For seizures, your provider will adjust your dose based on blood levels of the medication. Your dose might differ if you're an older adult or have kidney or liver problems.

interactions-icon

Interactions between Phenobarbital and other drugs

Phenobarbital may interact with certain medications or supplements. Always let your doctor and pharmacist know about any other medications or supplements (including prescribed and over-the-counter medications, vitamins, and dietary or herbal supplements) that you are currently taking. The list below does not include all possible drug interactions with Phenobarbital. Please note that only the generic name of each medication is listed below.

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking any of these medicines, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using medicines in this class with any of the following medicines is not recommended. Your doctor may decide not to treat you with a medication in this class or change some of the other medicines you take.

Using medicines in this class with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

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How much does Phenobarbital cost?

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contraindications-icon

Phenobarbital contraindications

Contraindications are specific health conditions or situations in which a person should not take a medication due to safety concerns. If you have any of the following conditions or if any of the following apply to you, let your healthcare provider know because Phenobarbital will not be safe for you to take.

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What are alternatives to Phenobarbital?

There are a number of medications that your doctor can prescribe in place of Phenobarbital. Compare a few possible alternatives below.
Phenobarbital
Used for:
$8.12Lowest GoodRx priceView prices
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$15.57Lowest GoodRx priceView prices
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$13.93Lowest GoodRx priceView prices
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Phenobarbital images

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References

Best studies we found

Benzoni, T., et al. (2023). Procedural Sedation. StatPearls.

Centers for Disease Control and Prevention. (2020). Types of Seizures.

Drugs and Lactation Database (LactMed). (2023). Phenobarbital. National Institute of Child Health and Human Development.

GoodRx Health has strict sourcing policies and relies on primary sources such as medical organizations, governmental agencies, academic institutions, and peer-reviewed scientific journals. Learn more about how we ensure our content is accurate, thorough, and unbiased by reading our editorial guidelines.

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