phenobarbital vs voriconazole
Side-by-side comparison of phenobarbital and voriconazole. Data from FDA drug databases (Orange Book, NDC Directory, recalls, shortages) covering 20,000+ approved drugs, plus CMS pricing; see our methodology.
major Known Drug Interaction
Carbamazepine (CYP450 Induction) Not Studied In Vivo or In Vitro , but Likely to Result in Significant Reduction Contraindicated Long Acting Barbiturates (e.g., phenobarbital, mephobarbital) (CYP450 Induction) Not Studied In Vivo or In Vitro , but Likely to Result in Significant Reduction Contraindicated Phenytoin (CYP450 Induction) Significantly Reduced Increase voriconazole maintenance dose from 4 mg/kg to 5 mg/kg IV every 12 hours or from 200 mg to 400 mg orally every 12 hours (100 mg to 200 mg orally every 12 hours in patients weighing less than 40 kg).
Recommendation: This combination is contraindicated and should be avoided. Talk to your doctor about using a different medication that does not interfere with your treatment.
Luminal
Vfend
Phenobarbital is a medicine that can help control seizures and calm you down. It belongs to a class of drugs called barbiturates.
Voriconazole (Vfend) is an antifungal medicine. It is used to treat serious fungal infections in adults and children 2 years and older.
This medicine is used to treat generalized and partial seizures. Seizures are caused by unusual electrical activity in the brain. Phenobarbital helps to reduce this activity and prevent seizures.
This medicine treats several types of fungal infections. It is used for invasive aspergillosis, a lung infection. It also treats candidemia (a blood infection) and other Candida infections in the skin, abdomen, kidney, bladder, and wounds. Voriconazole can also treat esophageal candidiasis (a throat infection) and serious infections caused by Scedosporium and Fusarium fungi.
Phenobarbital works by slowing down the activity of your brain and nervous system. It increases the effects of a natural chemical in the body called GABA. This helps to reduce seizures and promote relaxation.
Voriconazole belongs to a class of drugs called azole antifungals. It works by stopping the growth of fungi. It does this by interfering with the production of the fungal cell membrane.
- • Drowsiness
- • Sedation
- • Lethargy
- • Vertigo
- • Visual disturbances
- • Fever
- • Nausea
- • Rash
- • Vomiting
- Seizure 1,534
- Medicine interacting with another medicine 635
- Poisoning from different things 621
- Prolonged seizure 482
- Not responding to multiple medicines 442
- The medicine is interacting with another medicine 2,315
- Death 1,460
- Fever 1,411
- Lung infection 1,322
- The condition is getting worse 1,093
You should not take this medicine if you are allergic to barbiturates. Also, do not take it if you have a history of porphyria, severe liver problems, or breathing problems.
Voriconazole can cause serious liver problems. Your doctor will check your liver function with blood tests before and during treatment. This medicine can also cause heart rhythm problems. Make sure your potassium, magnesium, and calcium levels are normal before starting. Voriconazole can also cause severe skin reactions and make you sensitive to sunlight. Avoid sunlight and wear protective clothing. This medicine can harm an unborn baby, so women who can get pregnant should use effective birth control.
Tell your doctor if you are pregnant or plan to become pregnant. Phenobarbital can harm an unborn baby. Talk to your doctor about the risks and benefits of taking this medicine while breastfeeding.
Voriconazole can cause harm to an unborn baby. If you are pregnant or could become pregnant, talk to your doctor. It is not known if voriconazole passes into breast milk. Talk to your doctor about the risks and benefits of breastfeeding while taking this medicine.
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How to Read This phenobarbital vs voriconazole Comparison
phenobarbital is classified in the Anticonvulsant (Barbiturate) drug class, while voriconazole sits within the Azole Antifungal class. Drugs from different classes work through distinct mechanisms, so a head-to-head comparison illustrates trade-offs rather than equivalence. Both drugs are prescription-only, so a licensed provider must authorize use.
Adverse event totals above are pulled from the FDA's Adverse Event Reporting System (FAERS). For these top-ranked reactions alone, phenobarbital has 3,714 submissions while voriconazole has 7,601. Those figures reflect cumulative reporting volume, not per-patient risk, so older, widely dispensed drugs typically look worse on count alone. These two drugs have a known major interaction flagged in FDA labeling, attributed to phenobarbital causes the body to process voriconazole much faster than normal, which significantly lowers the amount of medicine in your system. this makes the treatment much less likely to fight off an infection.. Serious warnings, pregnancy guidance, and contraindications can differ even when indications overlap.
A table cannot substitute for clinical judgment. Effectiveness, tolerability, drug-drug interactions with your other medications, kidney and liver function, pregnancy status, insurance formulary, and price all feed into a decision that only a licensed prescriber can make responsibly. Data here is sourced from FDA Structured Product Labels (SPL) and FAERS, both of which update as manufacturers and clinicians submit new information. This page is for educational purposes only, is not medical advice, and should not be used to self-switch between phenobarbital and voriconazole - always consult your physician or pharmacist first.
Important: This comparison is for informational purposes only. Drug effects vary between individuals. Always consult your doctor or pharmacist for personalized medical advice.