Phenobarb® for Seizure Management and Sedation Support

What Phenobarb® Is and How It Works

Phenobarb® contains phenobarbital, a long-acting barbiturate used for seizure control and short-term sedation when prescribed. It is available as phenobarb tablet strengths such as 15 mg, 30 mg, 60 mg, and Phenobarb 64.8 mg, and as phenobarb syrup for flexible dosing. You can place a phenobarb online order at Canadian prices, even without insurance. YouDrugstore is a licensed Canadian pharmacy headquartered in Manitoba; prescriptions are reviewed by licensed pharmacists before dispensing, and we offer brand and generic options at Canadian prices with online ordering and live chat during office hours.

Phenobarbital enhances the effect of gamma-aminobutyric acid (GABA), an inhibitory neurotransmitter. By increasing the duration of chloride channel opening at the GABA-A receptor, it reduces neuronal excitability. This helps prevent seizure propagation and produces dose-dependent sedation.

Because of its long half-life (about 2–6 days), dosing is often once daily, commonly at bedtime. Steady-state blood levels may take 1–2 weeks or longer to reach. Discontinuation is usually gradual to limit withdrawal and seizure risk.

Dosage and Usage

• Follow your prescriber’s directions. Doses are individualized based on age, weight, seizure type, response, and serum levels.
• Common oral strengths include phenobarb 15mg, phenobarb 30 mg, phenobarb 60 mg, and Phenobarb 64.8 mg tablets. Liquid phenobarb syrup can help fine-tune pediatric doses.
• Swallow tablets with water. If using liquid, measure with an oral syringe or dosing spoon for accuracy.
• Take the dose at the same time each day. Bedtime dosing may reduce daytime drowsiness.
• If you miss a dose, take it when remembered unless it is close to the next dose. Do not double doses.
• Do not stop suddenly. Dose reductions are typically gradual to avoid withdrawal and rebound seizures.
• Avoid alcohol and limit other sedatives unless directed. Phenobarbital can add to CNS depression.
• Phenobarbital induces liver enzymes and can reduce the effect of hormonal contraceptives and other medicines. Ask your clinician or pharmacist about interactions.

• Store tablets and syrup at 15–25 °C (59–77 °F), dry, away from light.
• Keep in original, child-resistant packaging. Do not use after the labeled expiry date.
• For travel, keep medicine in your carry-on with the prescription label. Bring enough for delays.
• Do not freeze liquid. If the syrup changes color, odor, or forms crystals, contact your pharmacist.
• Separate from moisture sources in bathrooms. Use a weekly reminder to avoid missed doses.

Benefits and Savings

Phenobarb® is a long-established option for generalized tonic–clonic and focal seizures and for procedural sedation when indicated. The long half-life supports once-daily dosing. Multiple tablet strengths and a liquid formulation provide dosing flexibility across age groups. Many patients and clinicians value its predictable pharmacokinetics and the option to monitor serum levels.

Ordering through YouDrugstore can offer 60–80% savings versus typical US prices, which helps if you need phenobarb without insurance. Multi-month supplies and occasional bulk promotions may reduce your per-month phenobarb cost. You can turn on simple reorder reminders so you do not run out.

We work with licensed, vetted international partner pharmacies to source authentic brand medications alongside generics, giving you choice and value across a broad selection.

For current offers, see our phenobarb coupon page.

Side Effects and Safety

• Drowsiness, dizziness, and slowed reaction time
• Headache, nausea, vomiting, or constipation
• Ataxia (unsteadiness) or impaired coordination
• Depressed mood, irritability, or confusion
• Rash or photosensitivity
• Reduced libido or sexual dysfunction
• Vitamin D or folate depletion with long-term use

Serious effects can include respiratory depression, severe rash (Stevens–Johnson syndrome), liver problems, low blood counts, dependence, and withdrawal seizures if stopped abruptly. Phenobarbital is a strong enzyme inducer and interacts with many medicines, including opioids, benzodiazepines, oral contraceptives, warfarin, some antibiotics, and antifungals. Avoid alcohol. Those with severe respiratory disease, significant liver impairment, or a history of porphyria may not be candidates. For a broader look at interaction risks, see Drug Interactions The Top Interactions That Should Be On Your Radar.

Onset Time

Calming or sedative effects can appear within hours of a dose. For seizure prevention, consistent benefit often emerges as drug levels approach steady state, usually within 1–2 weeks. Doses may be adjusted based on clinical response and, when ordered, serum phenobarbital concentrations. Some individuals need several weeks to find a stable, effective dose.

Compare With Alternatives

Levetiracetam is a common first-line alternative for many seizure types. It has minimal drug–drug interactions and generally less sedation, but mood or irritability changes can occur. Dosing is usually twice daily, and therapeutic drug monitoring is not routine.

Lamotrigine is another option for focal and generalized seizures. Titration is slow to reduce rash risk, but it tends to be weight-neutral and less sedating than barbiturates. Drug interactions exist, particularly with valproate and enzyme inducers.

Valproate is effective for multiple generalized seizure types. It carries pregnancy-related risks and can affect weight and liver enzymes. It may be combined with other antiseizure drugs when monotherapy is insufficient.

You may also encounter combination products for gastrointestinal spasm that include belladonna alkaloids with phenobarbital (often referenced as phenobarb hyoscy atropine scop or bella phenobarb). These are different prescriptions and are not interchangeable with antiseizure phenobarbital therapy.

For educational context on seizure conditions, read Epilepsy When The Brain Goes Crazy But The Person With The Brain Isnt.

Combination Therapy

• With levetiracetam: Often well tolerated. Phenobarbital may increase sedation; adjust doses if needed.
• With lamotrigine: Enzyme induction by phenobarbital can lower lamotrigine levels; titration changes may be required.
• With valproate: Monitor for CNS effects and liver enzymes; dose adjustments may reduce side effects.
• With phenytoin or carbamazepine: Complex interactions are possible; levels and clinical response should guide dosing.
• Avoid combining with other sedatives or alcohol unless specifically directed, to limit respiratory depression.

Patient Suitability and Cost-Saving Tips

Phenobarb® may suit adults and children who need reliable seizure control, including generalized tonic–clonic or focal seizures. Those with severe breathing problems, significant liver disease, a history of porphyria, concurrent heavy alcohol use, or past barbiturate misuse may not be appropriate candidates. Use caution in older adults because of fall risk and cognitive effects. Pregnancy planning warrants a clinician discussion about risks and alternatives.

Because phenobarbital induces liver enzymes, it can reduce the effectiveness of hormonal contraceptives. Barrier or nonhormonal backup is often recommended. Review all prescription and over-the-counter medicines, vitamins, and herbal supplements for interactions.

To manage phenobarb price, consider a multi-month supply once your dose is stable. Bulk promotions can lower the average monthly phenobarb cost, and you can set gentle reminders to reorder before you run out. These steps may be helpful if you need phenobarb no insurance.

Phenobarb 30, phenobarb 60, and Phenobarb 64.8 mg tablets, as well as phenobarb 30 mg scored options and liquid forms, allow your prescriber to match dosing needs closely. In some regions, you may see names such as epilan c phenobarbitone; naming varies by market, but the active ingredient is phenobarbital.

Authoritative Sources

Health Canada Drug Product Database (search “phenobarbital”)

FDA Drug Database (phenobarbital labeling and approvals)

FDA Medication Guides for Patients

Order Phenobarb® from YouDrugstore.com: add to cart, upload your prescription, and we ship with prompt, express, cold-chain handling.

This material is educational and not a substitute for professional medical advice, diagnosis, or treatment. Always follow your prescriber’s instructions.