Phenobarbital Sodium has 24 known drug interactions based on U.S. FDA drug labeling data. Of these, 1 are contraindicated combinations that should be avoided entirely. 14 are classified as major interactions requiring close medical supervision. Notable interactions include combinations with Drugs That Prolong The Qt Interval, Acenocoumarol, Alcohol. Patients taking Phenobarbital Sodium should inform their healthcare provider of all current medications — including over-the-counter drugs and supplements — to avoid potentially harmful combinations. Data sourced from OpenFDA and the NIH National Library of Medicine.
- Total
- 24
- Contraindicated
- 1
- Major
- 14
- Moderate
- 9
Contraindicated (1)
- Phenobarbital Sodium + Drugs That Prolong The Qt Interval— Avoid concomitant use with phenobarbital.
Major (14)
- Phenobarbital Sodium + Acenocoumarol— Barbiturates induce hepatic microsomal enzymes resulting in increased metabolism and decreased anticoagulant response of…
- Phenobarbital Sodium + Alcohol— Concomitant use of alcohol with phenobarbital may produce additive central nervous system depressant effects.
- Phenobarbital Sodium + Antihistamines— Concomitant use of antihistamines with barbiturates may produce additive central nervous system depressant effects.
- Phenobarbital Sodium + Corticosteroids— Barbiturates enhance the metabolism of exogenous corticosteroids, requiring dosage adjustments when barbiturates are add…
- Phenobarbital Sodium + Dicumarol— Phenobarbital lowers plasma levels of dicumarol and decreases anticoagulant activity. Barbiturates induce hepatic micros…
- Phenobarbital Sodium + Doxycycline— Phenobarbital shortens the half-life of doxycycline for up to 2 weeks after discontinuation; clinical response should be…
- Phenobarbital Sodium + Estradiol— Phenobarbital may decrease the effect of estradiol by increasing its metabolism through enzyme induction.
- Phenobarbital Sodium + Estrone— Phenobarbital may decrease the effect of estrone through induction of hepatic microsomal enzymes.
- Phenobarbital Sodium + Monoamine Oxidase Inhibitors (Maois)— MAOIs prolong effects of barbiturates. Barbiturate metabolism is inhibited, requiring careful monitoring.
- Phenobarbital Sodium + Phenprocoumon— Barbiturates induce hepatic microsomal enzymes resulting in increased metabolism and decreased anticoagulant response of…
- Phenobarbital Sodium + Progesterone— Phenobarbital may decrease the effect of progesterone through induction of hepatic microsomal enzymes.
- Phenobarbital Sodium + Sedatives— Concomitant use of other sedatives with barbiturates may produce additive central nervous system depressant effects.
- Phenobarbital Sodium + Tranquilizers— Concomitant use of tranquilizers with barbiturates may produce additive central nervous system depressant effects.
- Phenobarbital Sodium + Warfarin— Barbiturates induce hepatic microsomal enzymes resulting in increased metabolism and decreased anticoagulant response of…
Moderate (9)
- Phenobarbital Sodium + Cns Depressants— Increased risk of sedation and respiratory depression with concomitant use. Closely monitor for adverse effects.
- Phenobarbital Sodium + Cyp3a Inducers— Inducers may decrease phenobarbital exposure, reducing efficacy and increasing risk of breakthrough seizures. Closely mo…
- Phenobarbital Sodium + Cyp3a4, 2b6, 2c, Ugt Substrates— Phenobarbital induces these enzymes, decreasing substrate exposure and potentially reducing efficacy. Monitor and consid…
- Phenobarbital Sodium + Griseofulvin— Phenobarbital appears to interfere with absorption of orally administered griseofulvin, decreasing its blood level. Conc…
- Phenobarbital Sodium + Mao Inhibitors— Inhibitors may increase phenobarbital exposure, increasing risk of adverse reactions. Closely monitor and consider dosag…
- Phenobarbital Sodium + Maois— MAOIs prolong the effects of barbiturates by inhibiting barbiturate metabolism.
- Phenobarbital Sodium + Phenytoin— The effect of barbiturates on phenytoin metabolism is variable and unpredictable. Blood levels of both drugs should be m…
- Phenobarbital Sodium + Valproate Sodium— Sodium valproate appears to decrease barbiturate metabolism. Barbiturate blood levels should be monitored and dosage adj…
- Phenobarbital Sodium + Valproic Acid— Valproic acid appears to decrease barbiturate metabolism. Barbiturate blood levels should be monitored and dosage adjust…