Phenobarbital 97.2mg Tablets
WARNING: The use of this drug along with opioid drugs may lead to severe side effects. This includes feeling very sleepy, slow or trouble breathing, passing out, and death. Opioid drugs include drugs like codeine, oxycodone, and morphine. Opioid drugs are used to treat pain and some are used to treat cough. If you have questions, talk with the doctor.If you are taking this drug with an opioid drug, get medical help right away if you feel very sleepy or dizzy; if you have slow, shallow, or trouble breathing; or if you pass out. Caregivers or others need to get medical help right away if the patient does not respond, does not answer or react like normal, or will not wake up. Using this drug for reasons that are not approved may increase the risk for drug use disorder. Misuse or abuse of this drug can lead to overdose or death, especially if used with certain other drugs, alcohol, or street drugs. Get medical help right away if you have changes in mood or behavior, suicidal thoughts or actions, seizures, or trouble breathing. @ COMMON USES: It is used to help control certain kinds of seizures.It is used to treat sleep problems.It may be given to you for other reasons. Talk with the doctor.
Drug Class
Anticonvulsant; Sedative-Hypnotic
Pharmacologic Class
Barbiturate; GABA-A Receptor Modulator
Pregnancy Category
Category D
FDA Approved
Jan 1970
DEA Schedule
Schedule IV
Overview
What is this medicine?
Phenobarbital is a medication used to control certain types of seizures (epilepsy) and to help with anxiety or trouble sleeping (sedation). It works by calming down overactive brain activity. It's a type of drug called a barbiturate.
How to Use This Medicine
Taking Your Medication
To use this medication correctly, follow your doctor's instructions and read all the information provided. You can take this medication with or without food. If it causes stomach upset, taking it with food may help.
Storing and Disposing of Your Medication
Keep your medication at room temperature, away from light and moisture. Store it in a dry place, avoiding the bathroom. Make sure to keep the lid tightly closed. To prevent accidental ingestion, store your medication in a secure location where children and pets cannot access it. Consider using a locked box or area to keep your medication safe. Keep all medications out of reach of pets.
What to Do If You Miss a Dose
If you miss a dose, take it as soon as you remember. However, if it's close to the time for your next scheduled dose, skip the missed dose and resume your regular dosing schedule. Do not take two doses at the same time or take extra doses to make up for a missed one.
To use this medication correctly, follow your doctor's instructions and read all the information provided. You can take this medication with or without food. If it causes stomach upset, taking it with food may help.
Storing and Disposing of Your Medication
Keep your medication at room temperature, away from light and moisture. Store it in a dry place, avoiding the bathroom. Make sure to keep the lid tightly closed. To prevent accidental ingestion, store your medication in a secure location where children and pets cannot access it. Consider using a locked box or area to keep your medication safe. Keep all medications out of reach of pets.
What to Do If You Miss a Dose
If you miss a dose, take it as soon as you remember. However, if it's close to the time for your next scheduled dose, skip the missed dose and resume your regular dosing schedule. Do not take two doses at the same time or take extra doses to make up for a missed one.
Lifestyle & Tips
- Take phenobarbital exactly as prescribed by your doctor. Do not stop taking it suddenly, as this can cause serious withdrawal symptoms or seizures.
- Avoid alcohol and other medications that cause drowsiness (e.g., cold/allergy medicines, pain relievers, sleeping pills) while taking phenobarbital, as this can increase sedation and breathing problems.
- Be cautious when driving or operating machinery until you know how phenobarbital affects you, as it can cause drowsiness, dizziness, and impaired coordination.
- If you are taking phenobarbital for seizures, carry identification stating your condition and medication.
- Women of childbearing potential should discuss contraception with their doctor, as phenobarbital can reduce the effectiveness of oral contraceptives. Use alternative or additional birth control methods.
- Maintain good oral hygiene, as long-term use can sometimes lead to gum overgrowth.
Available Forms & Alternatives
Available Strengths:
- Phenobarbital Sod 65mg/ml Inj, 1ml
- Phenobarbital 97.2mg Tablets
- Phenobarbital 64.8mg Tablets
- Phenobarbital 32.4mg Tablets
- Phenobarbital 16.2mg Tablets
- Phenobarb 130mg/ml Inj, 1ml
- Phenobarbital 100mg Tablets
- Phenobarbital 60mg Tablets
- Phenobarbital 60mg Tablets
- Phenobarbital 15mg Tablets
- Phenobarbital 16.2mg Tablets
- Phenobarbital 32.4mg Tablets
- Phenobarbital 64.8mg Tablets
- Phenobarbital 20mg/5ml Solution
- Phenobarbital 30mg Tablets
- Phenobarbital 97.2mg Tablets
- Phenobarbital 15mg Tablets
Dosing & Administration
Adult Dosing
Standard Dose:
Epilepsy: 60-200 mg/day orally, usually at bedtime. Sedation: 30-120 mg/day orally in 2-3 divided doses.
Dose Range:
30 - 200 mg
Condition-Specific Dosing:
epilepsy:
60-200 mg/day orally, once daily or in divided doses.
sedation:
30-120 mg/day orally in 2-3 divided doses.
Pediatric Dosing
Neonatal:
Loading dose: 15-20 mg/kg IV over 10-15 min. Maintenance: 3-4 mg/kg/day IV/PO in 1-2 divided doses (adjust based on levels).
Infant:
Loading dose: 15-20 mg/kg IV over 10-15 min. Maintenance: 3-5 mg/kg/day PO/IV in 1-2 divided doses.
Child:
Loading dose: 15-20 mg/kg IV over 10-15 min. Maintenance: 3-6 mg/kg/day PO/IV in 1-2 divided doses.
Adolescent:
Loading dose: 15-20 mg/kg IV over 10-15 min. Maintenance: 1-3 mg/kg/day PO/IV in 1-2 divided doses (max 200 mg/day).
Dose Adjustments
Renal Impairment:
Mild:
No specific adjustment, monitor for increased sedation.
Moderate:
Consider dose reduction by 25-50%, monitor serum levels and clinical response.
Severe:
Significant dose reduction (e.g., 50-75%), monitor serum levels closely. Avoid if possible.
Dialysis:
Hemodialysis removes phenobarbital. Supplemental dose may be needed post-dialysis. Peritoneal dialysis removes it slowly.
Hepatic Impairment:
Mild:
Use with caution, monitor LFTs and clinical response.
Moderate:
Dose reduction (e.g., 25-50%) recommended, monitor serum levels and LFTs closely.
Severe:
Contraindicated or significant dose reduction (e.g., 50-75%) with extreme caution and close monitoring of serum levels and LFTs.
Pharmacology
Mechanism of Action
Phenobarbital is a long-acting barbiturate that produces non-selective central nervous system (CNS) depression. It binds to a distinct allosteric site on the GABA-A receptor complex, enhancing the inhibitory effects of GABA by increasing the duration of chloride channel opening. This leads to hyperpolarization of the neuronal membrane, decreasing neuronal excitability and seizure propagation. At higher concentrations, it may also directly activate GABA-A receptors and inhibit excitatory glutamate receptors.
Pharmacokinetics
Absorption:
Bioavailability:
80-100%
Tmax:
2-18 hours (oral)
FoodEffect:
Food may slightly delay absorption but does not significantly affect bioavailability.
Distribution:
Vd:
0.5-1 L/kg
ProteinBinding:
20-45%
CnssPenetration:
Yes
Elimination:
HalfLife:
53-118 hours (adults), 40-70 hours (children), 100-200 hours (neonates)
Clearance:
0.003-0.007 L/kg/hr
ExcretionRoute:
Renal (25-50% unchanged, remainder as metabolites)
Unchanged:
25-50%
Pharmacodynamics
OnsetOfAction:
Oral: 30-60 minutes; IV: <5 minutes
PeakEffect:
Oral: 8-12 hours; IV: 30 minutes
DurationOfAction:
6-10 hours (sedation), up to 2-3 days (anticonvulsant effect due to long half-life)
Safety & Warnings
Side Effects
Urgent Side Effects: Seek Medical Help Right Away
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor or seek immediate medical attention:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin (with or without fever)
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Confusion
Changes in balance
Muscle spasms
Bad dreams
Restlessness
Hallucinations (seeing or hearing things that are not there)
Shortness of breath
Slow heartbeat
Feeling extremely tired or weak
Severe dizziness or fainting
Severe Skin Reaction: Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis
This rare but serious condition can cause severe health problems and may be life-threatening. Seek medical help immediately if you experience:
Red, swollen, blistered, or peeling skin (with or without fever)
Red or irritated eyes
Sores in your mouth, throat, nose, or eyes
Severe and Potentially Life-Threatening Side Effects
Some people taking medications like this one for seizures have experienced severe and potentially deadly side effects. Contact your doctor right away if you notice:
Swollen glands
Fever
Rash
Painful sores in the mouth or around the eyes
Chest pain
Signs of kidney problems, such as:
+ Unable to pass urine
+ Changes in the amount of urine passed
Signs of liver problems, such as:
+ Dark urine
+ Tiredness
+ Decreased appetite
+ Upset stomach or stomach pain
+ Light-colored stools
+ Vomiting
+ Yellow skin or eyes
Other Possible Side Effects
Most people experience no side effects or only mild side effects while taking this medication. However, if you notice any of the following side effects or any other unusual symptoms, contact your doctor or seek medical help:
Dizziness or drowsiness
Headache
Upset stomach or vomiting
Constipation
Feeling nervous or excitable
* Trouble sleeping
Reporting Side Effects
If you have questions or concerns about side effects, contact your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor or seek immediate medical attention:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin (with or without fever)
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Confusion
Changes in balance
Muscle spasms
Bad dreams
Restlessness
Hallucinations (seeing or hearing things that are not there)
Shortness of breath
Slow heartbeat
Feeling extremely tired or weak
Severe dizziness or fainting
Severe Skin Reaction: Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis
This rare but serious condition can cause severe health problems and may be life-threatening. Seek medical help immediately if you experience:
Red, swollen, blistered, or peeling skin (with or without fever)
Red or irritated eyes
Sores in your mouth, throat, nose, or eyes
Severe and Potentially Life-Threatening Side Effects
Some people taking medications like this one for seizures have experienced severe and potentially deadly side effects. Contact your doctor right away if you notice:
Swollen glands
Fever
Rash
Painful sores in the mouth or around the eyes
Chest pain
Signs of kidney problems, such as:
+ Unable to pass urine
+ Changes in the amount of urine passed
Signs of liver problems, such as:
+ Dark urine
+ Tiredness
+ Decreased appetite
+ Upset stomach or stomach pain
+ Light-colored stools
+ Vomiting
+ Yellow skin or eyes
Other Possible Side Effects
Most people experience no side effects or only mild side effects while taking this medication. However, if you notice any of the following side effects or any other unusual symptoms, contact your doctor or seek medical help:
Dizziness or drowsiness
Headache
Upset stomach or vomiting
Constipation
Feeling nervous or excitable
* Trouble sleeping
Reporting Side Effects
If you have questions or concerns about side effects, contact your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Seek Immediate Medical Attention If You Experience:
- Severe skin rash, blistering, or peeling (can be signs of Stevens-Johnson syndrome or toxic epidermal necrolysis)
- Fever, swollen glands, or sore throat (may indicate a serious reaction or blood problem)
- Unusual bleeding or bruising
- Yellowing of the skin or eyes (jaundice)
- Dark urine or pale stools
- Severe drowsiness, confusion, or difficulty breathing
- Unusual excitement, hyperactivity, or irritability (especially in children)
- Increased seizure frequency or new types of seizures
Before Using This Medicine
Before Taking This Medication: Important Information to Share with Your Doctor
It is essential to inform your doctor about the following conditions to ensure safe treatment:
Any allergies you have, including allergies to this medication, its components, or other substances. Describe the allergic reaction you experienced, including the symptoms that occurred.
Existing health conditions, such as:
+ Liver disease
+ Breathing problems, including shortness of breath
+ A history of porphyria
+ Heart problems, including:
- Heart failure
- Unstable angina (a specific type of chest pain)
- Abnormal heartbeat (e.g., long QT interval on an electrocardiogram (ECG))
+ Kidney disease
+ Low thyroid function (hypothyroidism)
+ A very narrow heart valve (aortic stenosis)
Recent heart attack
Use of medications that can cause abnormal heart rhythms (prolonged QT interval). Many drugs can cause this condition, so consult your doctor or pharmacist if you are unsure.
To ensure your safety, it is crucial to provide your doctor and pharmacist with a comprehensive list of:
All prescription and over-the-counter (OTC) medications you are taking
Natural products and vitamins you are using
* Existing health problems
This information will help your doctor determine whether it is safe to take this medication with your other medications and health conditions. Never start, stop, or change the dose of any medication without consulting your doctor.
It is essential to inform your doctor about the following conditions to ensure safe treatment:
Any allergies you have, including allergies to this medication, its components, or other substances. Describe the allergic reaction you experienced, including the symptoms that occurred.
Existing health conditions, such as:
+ Liver disease
+ Breathing problems, including shortness of breath
+ A history of porphyria
+ Heart problems, including:
- Heart failure
- Unstable angina (a specific type of chest pain)
- Abnormal heartbeat (e.g., long QT interval on an electrocardiogram (ECG))
+ Kidney disease
+ Low thyroid function (hypothyroidism)
+ A very narrow heart valve (aortic stenosis)
Recent heart attack
Use of medications that can cause abnormal heart rhythms (prolonged QT interval). Many drugs can cause this condition, so consult your doctor or pharmacist if you are unsure.
To ensure your safety, it is crucial to provide your doctor and pharmacist with a comprehensive list of:
All prescription and over-the-counter (OTC) medications you are taking
Natural products and vitamins you are using
* Existing health problems
This information will help your doctor determine whether it is safe to take this medication with your other medications and health conditions. Never start, stop, or change the dose of any medication without consulting your doctor.
Precautions & Cautions
Important Warnings and Cautions
When taking this medication, it is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, about your treatment.
Risk of Dependence and Withdrawal
The longer you take this medication and the higher the dose, the greater the risk of dependence and withdrawal. Before reducing the dose or stopping the medication, consult your doctor and follow their instructions carefully. Abruptly lowering the dose or stopping the medication can lead to withdrawal, which can be life-threatening. Seek immediate medical attention if you experience any adverse effects.
Tolerance and Dosage
If you have been taking this medication for an extended period or at high doses, you may develop tolerance, requiring higher doses to achieve the same effect. If you notice the medication is no longer working as well, contact your doctor. Do not take more than the prescribed dose.
Monitoring and Precautions
If you are taking this medication long-term, your doctor may recommend regular blood tests to monitor your condition. Discuss this with your doctor. Until you know how the medication affects you, avoid driving and other activities that require alertness. Additionally, refrain from consuming alcohol while taking this medication.
Interactions with Other Substances
Before using marijuana, cannabis, or prescription or over-the-counter medications that may cause drowsiness, consult your doctor. These substances can interact with this medication and increase the risk of adverse effects.
Suicidal Thoughts and Actions
Like other medications used to treat seizures, this medication may rarely increase the risk of suicidal thoughts or actions, particularly in individuals with a history of suicidal behavior. If you experience new or worsening symptoms such as depression, anxiety, restlessness, or mood changes, contact your doctor immediately. If you have suicidal thoughts or actions, seek help right away.
Special Considerations
If you are 65 or older, use this medication with caution, as you may be more susceptible to side effects. Children should also use this medication with caution, as the risk of certain side effects may be higher.
Birth Control and Pregnancy
Birth control pills and other hormone-based contraceptives may be less effective while taking this medication. Use two forms of birth control to prevent pregnancy. If you become pregnant or are planning to become pregnant, inform your doctor, as this medication may harm the unborn baby. If you take this medication during the third trimester of pregnancy, your newborn may experience side effects or withdrawal.
Breastfeeding
If you are breastfeeding, consult your doctor to discuss the potential risks to your baby.
Seizure Management
If your seizures change or worsen after starting this medication, consult your doctor to adjust your treatment plan.
When taking this medication, it is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, about your treatment.
Risk of Dependence and Withdrawal
The longer you take this medication and the higher the dose, the greater the risk of dependence and withdrawal. Before reducing the dose or stopping the medication, consult your doctor and follow their instructions carefully. Abruptly lowering the dose or stopping the medication can lead to withdrawal, which can be life-threatening. Seek immediate medical attention if you experience any adverse effects.
Tolerance and Dosage
If you have been taking this medication for an extended period or at high doses, you may develop tolerance, requiring higher doses to achieve the same effect. If you notice the medication is no longer working as well, contact your doctor. Do not take more than the prescribed dose.
Monitoring and Precautions
If you are taking this medication long-term, your doctor may recommend regular blood tests to monitor your condition. Discuss this with your doctor. Until you know how the medication affects you, avoid driving and other activities that require alertness. Additionally, refrain from consuming alcohol while taking this medication.
Interactions with Other Substances
Before using marijuana, cannabis, or prescription or over-the-counter medications that may cause drowsiness, consult your doctor. These substances can interact with this medication and increase the risk of adverse effects.
Suicidal Thoughts and Actions
Like other medications used to treat seizures, this medication may rarely increase the risk of suicidal thoughts or actions, particularly in individuals with a history of suicidal behavior. If you experience new or worsening symptoms such as depression, anxiety, restlessness, or mood changes, contact your doctor immediately. If you have suicidal thoughts or actions, seek help right away.
Special Considerations
If you are 65 or older, use this medication with caution, as you may be more susceptible to side effects. Children should also use this medication with caution, as the risk of certain side effects may be higher.
Birth Control and Pregnancy
Birth control pills and other hormone-based contraceptives may be less effective while taking this medication. Use two forms of birth control to prevent pregnancy. If you become pregnant or are planning to become pregnant, inform your doctor, as this medication may harm the unborn baby. If you take this medication during the third trimester of pregnancy, your newborn may experience side effects or withdrawal.
Breastfeeding
If you are breastfeeding, consult your doctor to discuss the potential risks to your baby.
Seizure Management
If your seizures change or worsen after starting this medication, consult your doctor to adjust your treatment plan.
Overdose Information
Overdose Symptoms:
- Severe drowsiness or coma
- Slow, shallow, or stopped breathing
- Slow heartbeat
- Low blood pressure
- Cold, clammy skin
- Pinpoint pupils
- Lack of reflexes
- Shock
What to Do:
Seek immediate emergency medical attention. Call 911 or your local poison control center (1-800-222-1222). Overdose can be fatal.
Drug Interactions
Contraindicated Interactions
- Porphyria (acute intermittent porphyria)
- Severe respiratory depression
- Severe hepatic impairment
Major Interactions
- Other CNS depressants (e.g., opioids, benzodiazepines, alcohol, tricyclic antidepressants) - increased sedation and respiratory depression
- Valproic acid - increased phenobarbital levels, decreased valproic acid levels
- Warfarin - decreased anticoagulant effect (CYP induction)
- Oral contraceptives - decreased contraceptive efficacy (CYP induction)
- Corticosteroids - decreased corticosteroid effect (CYP induction)
- Doxycycline - decreased doxycycline levels (CYP induction)
- Griseofulvin - decreased griseofulvin levels (CYP induction)
- Lamotrigine - decreased lamotrigine levels (CYP induction)
- Tiagabine - decreased tiagabine levels (CYP induction)
- Felodipine, Nimodipine, Nisoldipine - decreased calcium channel blocker levels (CYP induction)
- Ritonavir, Saquinavir - decreased antiretroviral levels (CYP induction)
Moderate Interactions
- Acetaminophen - increased risk of hepatotoxicity with chronic phenobarbital use
- Carbamazepine - decreased carbamazepine levels, increased phenobarbital levels
- Phenytoin - variable effects on phenytoin levels (increase or decrease)
- Topiramate - decreased topiramate levels
- Zidovudine - decreased zidovudine levels
- Digoxin - decreased digoxin levels
- Quinidine - decreased quinidine levels
Minor Interactions
- Folic acid - may decrease folic acid levels
- Vitamin D - may decrease vitamin D levels
Monitoring
Baseline Monitoring
Complete Blood Count (CBC)
Rationale: To establish baseline and monitor for blood dyscrasias (e.g., megaloblastic anemia, thrombocytopenia, leukopenia).
Timing: Prior to initiation
Liver Function Tests (LFTs)
Rationale: To establish baseline and monitor for hepatic dysfunction.
Timing: Prior to initiation
Renal Function Tests (BUN, Creatinine)
Rationale: To establish baseline and guide dosing in renal impairment.
Timing: Prior to initiation
Serum Phenobarbital Levels
Rationale: To establish baseline and guide initial dosing, especially in complex cases or when rapid therapeutic levels are desired.
Timing: Prior to initiation (optional, but useful)
Routine Monitoring
Serum Phenobarbital Levels
Frequency: Weekly during initial titration, then every 1-3 months until stable, then every 6-12 months or as clinically indicated.
Target: 15-40 mcg/mL (therapeutic range for epilepsy)
Action Threshold: Levels outside therapeutic range, signs of toxicity (e.g., excessive sedation, nystagmus, ataxia) or inadequate seizure control.
Liver Function Tests (LFTs)
Frequency: Every 6-12 months, or more frequently if clinically indicated or with signs of hepatic dysfunction.
Target: Within normal limits
Action Threshold: Significant elevation of liver enzymes (e.g., >3x ULN), signs of liver injury.
Complete Blood Count (CBC)
Frequency: Every 6-12 months, or more frequently if clinically indicated or with signs of hematologic abnormalities.
Target: Within normal limits
Action Threshold: Significant decrease in cell counts (e.g., anemia, leukopenia, thrombocytopenia).
Clinical Assessment (seizure control, sedation, cognitive function, mood)
Frequency: At every visit
Target: Optimal seizure control with minimal side effects
Action Threshold: Increased seizure frequency, excessive sedation, cognitive impairment, mood changes, or other adverse effects.
Symptom Monitoring
- Excessive sedation or drowsiness
- Dizziness
- Ataxia (unsteadiness)
- Nystagmus (involuntary eye movements)
- Cognitive impairment (memory, concentration difficulties)
- Mood changes (irritability, depression, hyperactivity in children)
- Skin rash (Stevens-Johnson syndrome, toxic epidermal necrolysis)
- Fever, sore throat, unusual bruising or bleeding (signs of blood dyscrasias)
- Yellowing of skin or eyes, dark urine, abdominal pain (signs of liver dysfunction)
- Respiratory depression (especially with overdose or co-administration of other CNS depressants)
Special Patient Groups
Pregnancy
Phenobarbital is classified as Pregnancy Category D. It is associated with an increased risk of congenital malformations (e.g., cardiac defects, cleft lip/palate, neural tube defects) and a neonatal withdrawal syndrome (irritability, hypertonia, tremors, feeding difficulties) if used during pregnancy. Use only if the potential benefit outweighs the potential risk to the fetus, and consider folic acid supplementation.
Trimester-Specific Risks:
First Trimester:
Increased risk of major congenital malformations (e.g., cardiac, oral clefts, neural tube defects).
Second Trimester:
Continued risk of fetal exposure and potential for developmental effects.
Third Trimester:
Risk of neonatal withdrawal syndrome (irritability, hypertonia, tremors, feeding difficulties) and hemorrhagic disease of the newborn (due to vitamin K deficiency).
Lactation
Phenobarbital is excreted into breast milk (Lactation Risk Category L3 - Moderately Safe). It can cause sedation, poor feeding, and weight gain in breastfed infants. Monitor infants for drowsiness, poor suckling, and developmental milestones. Consider therapeutic drug monitoring in the infant if concerns arise. Breastfeeding may be acceptable with careful monitoring, especially for older infants.
Infant Risk:
Moderate risk of sedation, poor feeding, and withdrawal symptoms upon discontinuation of breastfeeding. Monitor for lethargy, poor weight gain, and respiratory depression.
Pediatric Use
Children, especially younger ones, may experience paradoxical hyperactivity or irritability. Neonates and infants have significantly longer half-lives, requiring careful dosing and monitoring. Long-term use can affect bone mineral density and vitamin D levels. Close monitoring of serum levels is crucial due to age-dependent pharmacokinetic variability.
Geriatric Use
Elderly patients are more susceptible to the CNS depressant effects (sedation, dizziness, ataxia) and may have impaired hepatic or renal function, requiring lower doses and careful titration. Increased risk of falls and cognitive impairment. Start with lower doses and titrate slowly.
Clinical Information
Clinical Pearls
- Phenobarbital has a very long half-life, meaning it takes several days to reach steady-state levels and for effects to wear off after discontinuation. This also means missed doses are less critical than with shorter-acting AEDs.
- Due to its enzyme-inducing properties, phenobarbital can significantly reduce the effectiveness of many other medications, including oral contraceptives, warfarin, and certain antiretrovirals. Always review concomitant medications.
- Abrupt discontinuation can precipitate severe withdrawal symptoms, including status epilepticus. Taper slowly over weeks to months.
- Therapeutic drug monitoring (TDM) is essential for phenobarbital due to its narrow therapeutic index and variable pharmacokinetics.
- While effective, its side effect profile (sedation, cognitive impairment, behavioral changes) and drug interaction potential often make it a second or third-line agent for epilepsy, especially in adults. It remains a first-line option for neonatal seizures.
- Patients should be advised to carry medical identification if taking phenobarbital for epilepsy.
Alternative Therapies
- For Epilepsy: Levetiracetam, Valproic acid, Carbamazepine, Phenytoin, Lamotrigine, Topiramate, Oxcarbazepine, Zonisamide, Gabapentin, Pregabalin.
- For Sedation/Anxiety: Benzodiazepines (e.g., Lorazepam, Diazepam), Buspirone, Antidepressants (for anxiety), Z-drugs (for insomnia).
Cost & Coverage
Average Cost:
$10 - $50 per 30 tablets (97.2mg)
Generic Available:
Yes
Insurance Coverage:
Tier 1 or Tier 2 (Generic)
General Drug Facts
If your symptoms or health issues persist or worsen, it's essential to contact your doctor for further guidance. To ensure your safety, never share your medication with others or take someone else's medication. Some medications may come with an additional patient information leaflet, so be sure to check with your pharmacist for more information. If you have any questions or concerns about your medication, don't hesitate to reach out to your doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call your local poison control center or seek emergency medical attention. When seeking help, be prepared to provide details about the medication taken, the amount, and the time it happened.