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Phenobarbital Unit Converter
Phenobarbital is a barbiturate anticonvulsant used to treat various types of seizures (especially in children) and status epilepticus. Due to its narrow therapeutic index and potential for toxicity, therapeutic drug monitoring (TDM) is essential.
This converter facilitates switching between the standard mass units (µg/mL, mg/L) used in most clinical laboratories and the SI molar units (µmol/L) used in international research and European settings.
Mass Units
StandardMicrograms per milliliter (Numerically equivalent to mg/L).
SI / Molar Units
Clinical Context
Therapeutic Range (Trough): Generally 15 – 40 µg/mL (65 – 172 µmol/L).
Levels are typically monitored immediately prior to the next dose (trough level).
Toxic Levels:
• > 40 µg/mL: Potential for sedation, nystagmus, and ataxia.
• > 60-80 µg/mL: Serious toxicity (coma, respiratory depression).
Conversion Logic:
Molecular Weight of Phenobarbital: 232.24 g/mol.
1 µg/mL ≈ 4.306 µmol/L.
1 µmol/L ≈ 0.232 µg/mL.
Clinical References
How to Use This Converter
Follow these steps to normalize Phenobarbital levels.
Enter Values
Input your laboratory results into the corresponding unit field (e.g., µg/mL).
Automatic Conversion
The calculator converts between mass units and the SI molar unit (µmol/L).
Reset
Use the Clear button to reset all fields.
Frequently Asked Questions
Trough levels are typically drawn just before the morning dose. Phenobarbital has a long half-life, so steady state may take 2-3 weeks to achieve.
Yes, it is a barbiturate and can be habit-forming. Abrupt discontinuation can cause severe withdrawal seizures.