For patients taking estrogens for other indications, like hormone replacement, monitor the patient for signs and symptoms of reduced therapeutic efficacy or need for dosage adjustment. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. For hormonal contraceptives, this interaction could result in unintended pregnancy or breakthrough bleeding. Coadministration may increase the risk of CNS depressant-related side effects. If therapy with barbiturates is initiated or discontinued during treatment with ropinirole, adjustment of ropinirole dose may be required. Consult IV compatibility resources. (Minor) Chronic therapy with barbiturates can increase the metabolism and decrease the effectiveness of acetaminophen. Coadministration with another strong CYP3A4 inducer significantly decreased ivacaftor exposure by approximately 9-fold. Educate patients about the risks and symptoms of respiratory depression and sedation. In addition, phenobarbital toxicity has been reported to have occurred in a patient on chronic phenobarbital treatment after diclofenac initiation. Close monitoring of drug concentrations and/or therapeutic and adverse effects is required. (Minor) Chronic therapy with barbiturates can increase the metabolism and decrease the effectiveness of acetaminophen. In addition, the exposure of sirolimus may be altered via P-glycoprotein (P-gp) transport. Monitor for reduced efficacy of tramadol and signs of opioid withdrawal. Bupropion; Naltrexone: (Moderate) Bupropion may interact with drugs that induce hepatic microsomal isoenzyme function via CYP2B6 such as the barbiturates. Barbiturates such as phenobarbital and primidone may decrease the systemic exposure of sirolimus. Barbiturates are no longer considered an acceptable treatment for insomnia due to a significant adverse effect profile, narrow therapeutic index, tolerance and dependence, and availability of safer alternatives. An enhanced CNS depressant effect may occur when carbetapentane is combined with other CNS depressants including barbiturates. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. When these drugs are coadministered, there is a potential for treatment failure and/or the development of rilpivirine or NNRTI resistance. Due to immature hepatic and renal function (particularly in the first few weeks of life), neonates (especially premature neonates) must be carefully monitored via serum concentrations and clinical status during phenobarbital therapy. Concurrent use of cariprazine with CYP3A4 inducers, such as primidone or barbiturates, has not been evaluated and is not recommended because the net effect on active drug and metabolites is unclear. Conjugated Estrogens; Bazedoxifene: (Moderate) Barbiturates can accelerate the hepatic clearance of estrogens. It is recommended to avoid this combination when dihydrocodeine is being used for cough. Limit the use of opioid pain medications with a barbiturate to only patients for whom alternative treatment options are inadequate. Drospirenone; Estradiol: (Moderate) Barbiturates can accelerate the hepatic clearance of estrogens. Slow Intravenous (IV) injection administration:IV injection should only be used in emergency situations or when other routes are not feasible; intravenous administration is for hospitalized patients only.Aqueous dilutions of phenobarbital are not generally stable. (Minor) Chronic therapy with barbiturates can increase the metabolism and decrease the effectiveness of acetaminophen. Monitor patients closely for signs and symptoms of methemoglobinemia if coadministration is necessary. Phenobarbital induces the CYP3A4 metabolism of elvitegravir. Consider alternative agents with less potential for interaction. Coadministration with another strong CYP3A4 inducer decreased tadalafil exposure by 88%. (Major) Concurrent use of ritonavir with phenobarbital or other barbiturates should be done cautiously. Barbiturates induce CYP3A4; meperidine is a CYP3A4 substrate. Educate patients about the risks and symptoms of respiratory depression and sedation. Coadministration of phenobarbital with everolimus (Zortress) is not recommended without close monitoring of everolimus whole blood trough concentrations. Phenobarbital is recommended for neonatal abstinence syndrome in nonopiate- or polydrug-exposed infants. Barbiturates induce CYP3A4, an isoenzyme partially responsible for the metabolism of dihydrocodeine. Abacavir; Dolutegravir; Lamivudine: (Major) Avoid concurrent use of dolutegravir with phenobarbital, as coadministration may result in decreased dolutegravir plasma concentrations. Taking these drugs together may decrease sofosbuvir plasma concentrations, potentially resulting in loss of antiviral efficacy. For patients taking estrogens for other indications, like hormone replacement, monitor the patient for signs and symptoms of reduced therapeutic efficacy or need for dosage adjustment. (Major) Closely monitor for decreased phenobarbital efficacy during coadministration; clinical monitoring of phenobarbital concentrations with dosage titration if necessary is also warranted. Monitor for reduced efficacy of hydrocodone and signs of opioid withdrawal. Educate patients about the risks and symptoms of respiratory depression and sedation. Consider using an alternative agent in place of phenobarbital. Discontinuation of a barbiturate may increase the risk of increased opioid-related adverse reactions, such as fatal respiratory depression. (Minor) It is possible that a decrease in exposure of pioglitazone will occur when coadministered with drugs that induce CYP2C8 including phenobarbital. Brompheniramine: (Moderate) Additive CNS depression may occur if barbiturates are co-used with sedating antihistamines, such as brompheniramine. Ticagrelor is a substrate of CYP3A4/5 and concomitant use with phenobarbital substantially decreases ticagrelor exposure which may decrease the efficacy of ticagrelor. Triprolidine: (Moderate) Additive CNS depression may occur if barbiturates are used concomitantly with triprolidine. Barbiturates may cause additive sedation or other CNS depressive effects when used concurrently with topiramate. Hydrochlorothiazide, HCTZ; Irbesartan: (Moderate) Barbiturates may potentiate orthostatic hypotension when used concurrently with thiazide diuretics. For hormonal contraceptives, this interaction could result in unintended pregnancy or breakthrough bleeding. It is recommended to avoid this combination when hydrocodone is being used for cough. Reduce the initial oxymorphone dosage by 1/3 to 1/2. Studies indicate there is a loss of effectiveness of barbiturates for sleep induction and sleep maintenance after 2 weeks. Hydrochlorothiazide, HCTZ: (Moderate) Barbiturates may potentiate orthostatic hypotension when used concurrently with thiazide diuretics. The elimination half-life of phenobarbital can be extremely prolonged in neonates. When the potent CYP3A4 inducer is discontinued, the quetiapine dose should be reduced to the original dose within 1 to 2 weeks. Thalidomide: (Major) The use of barbiturate anxiolytics, sedatives, or hypnotics with thalidomide may cause an additive sedative effect and should be avoided. Dexamethasone: (Moderate) Coadministration may result in decreased exposure to dexamethasone. Limit the use of opioid pain medications with a barbiturate to only patients for whom alternative treatment options are inadequate. Monitor for additive CNS and respiratory effects, and warn about the potential effects to driving and other activities. When using Risperdal Consta, the patient will require close monitoring for 4 to 8 weeks when starting an inducer. In addition, barbiturates are CYP3A4 inducers and may decrease plasma quinine concentrations. Avoid abrupt discontinuation of phenobarbital after prolonged use to limit drug withdrawal. Lapatinib: (Major) Avoid coadministration of lapatinib with phenobarbital due to decreased plasma concentrations of lapatinib. Avanafil: (Minor) Avanafil is a substrate of and primarily metabolized by CYP3A4. Pregnancy has been reported during therapy with both estrogen- and/or progestin-based oral contraceptives in patients receiving barbiturates (e.g., phenobarbital). Barbiturates induce CYP3A4. Limit the use of opioid pain medications with a barbiturate to only patients for whom alternative treatment options are inadequate. Phenobarbital is available in generic form. In adults receiving 662 mg, 882 mg, or 1,064 mg of Aristada and receiving a strong CYP3A4 inducer, no dosage adjustment is necessary; however, the 441 mg dose should be increased to 662 mg if the CYP inducer is added for more than 2 weeks. It is recommended to avoid this combination when hydrocodone is being used for cough. Barbiturates induce CYP3A4; hydrocodone is a CYP3A4 substrate. Phenobarbital requires a prescription from your veterinarian and is classified as a schedule IV controlled substance. Phenobarbital may cause blurred vision, drowsiness, dizziness, or mental status changes, especially with initial use. Amitriptyline; Chlordiazepoxide: (Moderate) Additive CNS and/or respiratory depression may occur. Vilazodone is primarily metabolized by CYP3A4 and phenobarbital is a strong CYP3A4 inducer. Abiraterone: (Major) Avoid coadministration of abiraterone with phenobarbital if possible due to decreased plasma concentrations of abiraterone. Do not use commercially available phenobarbital sodium injection subcutaneously.Inject subcutaneously taking care not to inject intradermally. Fedratinib: (Major) Avoid coadministration of fedratinib with phenobarbital as concurrent use may decrease fedratinib exposure which may result in decreased therapeutic response. Barbiturates induce CYP2C19 and rabeprazole is a CYP2C19 substrate. Observe patients for evidence of reduced donepezil efficacy if these agents are prescribed concurrently. Anticonvulsant serum concentrations should be monitored closely if these agents are added; the patient should be observed for changes in the clinical efficacy of the antiretroviral or anticonvulsant regimen. If methemoglobinemia occurs or is suspected, discontinue penicillin G procaine and any other oxidizing agents. Barbiturates should be used cautiously in patients with renal impairment. Triamcinolone: (Moderate) Coadministration may result in decreased exposure to triamcinolone. Discontinuation of a barbiturate may increase the risk of increased opioid-related adverse reactions, such as fatal respiratory depression. Hundreds risk jail to import illegal drug The hypnotic effects of barbiturates can be reduced by caffeine administration. Avoid using a strong inducer of CYP3A4 and/or P-gp if possible during the 1-month injectable dosing interval of Invega Sustenna or the 3-month injectable dosing interval of Invega Trinza. Barbiturates readily cross the placental barrier and are distributed throughout fetal tissues with highest concentrations in the placenta, fetal liver, and brain. Consider other antihyperglycemic therapy in patients who require additional glycemic control. Doravirine is a CYP3A4 substrate; phenobarbital is a strong CYP3A4 inducer. Coadministration of oxcarbazepine (600 to 1,800 mg/day) with phenobarbital (100 to 150 mg/day) decreased the plasma concentration of MHD by 25% and increased the plasma concentration of phenobarbital by 14%. Strong CYP3A4 inducers, such as phenobarbital, significantly decrease plasma naldemedine concentrations and may decrease the efficacy of naldemedine treatment. Coadministration may result in decreased rilpivirine serum concentrations, which could cause impaired virologic response to rilpivirine. In rare cases, this has caused anticonvulsant-induced rickets and osteomalacia. It may be used to help you sleep or may be used to help control seizures. Monitor for signs of opioid withdrawal. Phenobarbital induces the CYP3A4 metabolism of elvitegravir. Cyclosporine: (Major) Phenobarbital may induce cyclosporine metabolism, thereby increasing the clearance of cyclosporine. Additionally, barbiturates may increase the metabolism of estazolam. Additionally, barbiturates may increase the metabolism of N-desmethyldiazepam, the active metabolite of clorazepate. This means it is still under development and may contain inaccuracies. Discontinuation of a barbiturate may increase the risk of opioid-related adverse reactions, such as fatal respiratory depression. Phenobarbital Tablets (15 mg, 30 mg, 60 mg, 100 mg) Drug Information. Barbiturates induce CYP3A4; hydrocodone is a CYP3A4 substrate. For patients taking estrogens for other indications, like hormone replacement, monitor the patient for signs and symptoms of reduced therapeutic efficacy or need for dosage adjustment. Phenobarbital sodium injection is incompatible with many other injectable medications.Adult patients: The maximum rate of slow IV injection for adults is 60 mg/minute in less-acute situations and a maximum of 75—100 mg/min for status epilepticus, but hypotension or the need for assisted ventilation may occur when the drug is administered at these rates. Monitor for decreased response to triamcinolone during concurrent use. Coadministration may result in decreased zanubrutinib exposure and reduced efficacy. An enhanced effect of the displaced drug may occur. Increased doses of anticonvulsants may be required due metabolism induction by ritonavir. Phenobarbital is only available generically (without a brand name). The clinical significance of this interaction has not been established, but dosage adjustments of fenoprofen may be necessary with concurrent administration of phenobarbital or following initiation or withdrawal of the drug. Additionally, concomitant use of hydrocodone with a barbiturate can decrease hydrocodone concentrations; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence. Patients receiving phenobarbital in combination with pioglitazone should be monitored for changes in glycemic control; dosage adjustments may be necessary. (Moderate) Due to high protein binding, salicylates could be displaced from binding sites, or could displace other highly protein-bound drugs such as barbiturates. Abiraterone is a CYP3A4 substrate and phenobarbital is a strong CYP3A4 inducer. For hormonal contraceptives, this interaction could result in unintended pregnancy or breakthrough bleeding. Repeated use of phenobarbital during the third trimester can cause physical dependence in the neonate. The primary analysis consisted of 199 placebo-controlled clinical studies with a total of 27,863 patients in drug treatment groups and 16,029 patients in placebo groups (>= 5 years of age). It is not clear if these pharmacokinetic interactions affect the therapeutic efficacy of albendazole in the treatment of neurocysticercosis. Acetazolamide can also increase the rate of excretion of weakly acidic drugs, such as barbiturates. Pregnancy has been reported during therapy with both estrogen- and/or progestin-based oral contraceptives in patients receiving barbiturates (e.g., phenobarbital). It is recommended to avoid this combination when codeine is being used for cough. Because the dose of the sufentanil sublingual tablets cannot be titrated, consider an alternate opiate if barbiturates must be administered. Intravenous administration of phenobarbital sodium should generally be reserved for emergency settings; close supervision is necessary in a monitored unit. Barbiturates induce CYP3A4. If a breast-feeding infant experiences an adverse effect related to a maternally administered drug, healthcare providers are encouraged to report the adverse effect to the FDA. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Dolutegravir; Rilpivirine: (Severe) Concurrent use of phenobarbital and rilpivirine is contraindicated. In a drug interaction study, coadministration with another strong CYP3A4 inducer decreased nilotinib exposure by approximately 80%. Cobimetinib is a CYP3A substrate in vitro; phenobarbital is a strong inducer of CYP3A. Barbiturates induce CYP3A4; hydrocodone is a CYP3A4 substrate. In drug interaction studies, administration of a dual P-gp and CYP3A4 inducer with nintedanib decreased the AUC of nintedanib by 50%. The clinical effect of this interaction on the efficacy of donepezil has not been determined. If treatment with phenobarbital cannot be avoided during breast-feeding, the nursing infant should be monitored for sedation, respiratory depression, apnea, and other signs of CNS depression. Avoid coadministration of atazanavir with phenobarbital unless atazanavir is boosted with ritonavir. During acute overdoses, barbiturates can enhance the formation of toxic acetaminophen metabolites. Acetaminophen; Dextromethorphan; Doxylamine: (Moderate) Because doxylamine can cause pronounced sedation, an enhanced CNS depressant effect may occur when it is combined with other CNS depressants including anxiolytics, sedatives, and hypnotics, such as barbiturates. It is recommended to avoid this combination when hydrocodone is being used for cough. Cannabidiol is metabolized by CYP3A4; in vitro data predicts inhibition of CYP2C9 by cannabidiol. For patients regularly taking a barbiturate, an alternative or back-up method of contraception may be advisable to ensure contraceptive reliability during the use of the barbiturate, and for 1 month following the discontinuation of barbiturate use. PDR.net is to be used only as a reference aid. These decreases in exposure to rivaroxaban may decrease efficacy. Fetal blood levels approach maternal blood levels following parenteral administration. Barbiturates are CYP2C9, CYP2C19, and CYP3A4 inducers. An enhanced CNS depressant effect may occur when carbetapentane is combined with other CNS depressants including barbiturates. Monitor for additive CNS and respiratory effects, and warn about the potential effects to driving and other activities.