Omeprazole diazepam

Substrates for this enzyme include (R)-mephobarbital, moclobemide, proguanil, diazepam, omeprazole, and imipramine, which do not show obvious structural or... 

Zomorodi K, Houston JB. Diazepam-omeprazole inhibition interaction an in vitro investigation using human liver microsomes. Br J Clin Pharmacol 1996 42(2) 157-62. 

Simultaneous acetaminophen, amoxicillin, aspirin, caffeine, cimetidine, codeine, diazepam, omeprazole, ranitidine, theophylline Interfering imipramine... 

Cytochrome P450 2C19, also termed S-mephenytoin hydroxylase, is a mixed-function oxidase localized in the endoplasmic reticulum which is responsible for the biotransformation of S-mephenytoin, some barbiturates, almost all proton pump inhibitors such as omeprazole, diazepam and others. 

Cytochrome P450 2C19 Deficient activity in about 3% of Caucasian populations and in about 20% of Asian populations. Prolonged action of several CYP2C19 inactivated drugs like omeprazole or diazepam in the poor metabolizers. 

While generally not of major concern, omeprazole may inhibit the metabolism of warfarin, diazepam, and phenytoin lansoprazole may decrease theophylline concentrations. Drug interactions with omeprazole are of particular concern in patients who are considered slow metabolizers, as are approximately 3% of the Caucasian population. Unfortunately, it is unclear which patients have the polymorphic gene variation that makes them slow metabolizers.17 The metabolism of esomeprazole may also be altered in patients with this polymorphic gene variation. Patients on potentially interacting drugs should be monitored for development of drug-related problems. 

Diazepam (Valium, Diastat) [C-IVj [Anxiolytic, Skeletal Muscle Relaxant, Anticonvulsant, Sedative/Hypnotic/ Benzodiazepine] Uses Anxiety, EtOH withdrawal, muscle spasm, status epilepticus, panic disorders, amnesia, preprocedure sedation Action Benzodiazepine Dose Adults. Status epilepticus 5-10 mg IV/IM Anxiety 2-5 mg IM/IV Preprocedure 5-10 mg IV just prior to procedure Peds. Status epilepticus 0.5-2 mg IV/IM Sedation 0.2-0.5 mg/kg IV (onset w/in 5IV and 30 min IM duration about 1 h IV and IM) Caution [D, / -] Contra Coma, CNS depression, resp d es-sion, NAG, severe uncontrolled pain, PRG Disp Tabs 2, 5, 10 mg soln 1, 5 mg/mL inj 5 mg/mL rectal gel 2.5, 5, 10, 20 mg/mL SE Sedation, amnesia, bradycardia, i BP, rash, X resp rate Interactions T Effects W/ antihistamines, azole antifungals, BBs, CNS depressants, cimetidine, ciprofloxin, disulfiram, INH, OCP, omeprazole, phenytoin, valproic acid, verapamil, EtOH, kava kava, valman T effects OF digoxin, diuretics X effects w/ barbiturates, carbamazepine. 

Substrates CYP2C19 Diazepam, lansoprazole, omeprazole, phenytoin. 

Omeprazole can inhibit the metabolism of drugs metabolised mainly by the cytochrome P-450 enzyme subfamily 2C (diazepam, phenytoin), but not of those metabolished by subfamilies lA (caffeine, theophylline), 2D (metoprolol, propranolol), and 3A (ciclosporin, lidocaine (lignocaine), quinidine). Since relatively few drugs are metabolised mainly by 2C compared with 2D and 3A, the potential for omeprazole to interfere with the metabolism of other drugs appears to be limited, but the half lives of diazepam and phenytoin are prolonged as much as by cimetidine. 

C19 Diazepam, S-mephenytoin, naproxen, nirvanol, omeprazole, propranolol Barbiturates, rifampin /3-benzylnirvanol, N3- benzylphenobarbital, fluconazole... 

A2 Tertiary amine TCAs, duloxetine, theophylline, phenacetin, TCAs (demethylation), clozapine, diazepam, caffeine Fluvoxamine, fluoxetine, moclobemide, ramelteon Tobacco, omeprazole... 

C19 TCAs, citalopram (partly), warfarin, tolbutamide, phenytoin, diazepam Fluoxetine, fluvoxamine, sertraline, imipramine, ketoconozole, omeprazole Rifampin... 

C19. V-Mcphenyloin, diazepam, phenytoin, omeprazole, indomethacin, impramine, propanolol, proguanil [S-Mephentoin (4 -OH)]... 

Sultana et al. [88] developed a reversed-phase HPLC method for the simultaneous determination of omeprazole in Risek capsules. Omeprazole and the internal standard, diazepam, were separated by Shim-pack CLC-ODS (0.4 x 25 cm, 5 m) column. The mobile phase was methanol-water (80 20), pumped isocratically at ambient temperature. Analysis was run at a flow-rate of 1 ml/min at a detection wavelength of 302 nm. The method was specific and sensitive with a detection limit of 3.5 ng/ml at a signal-to-noise ratio of 4 1. The limit of quantification was set at 6.25 ng/ml. The calibration curve was linear over a concentration range of 6.25—1280 ng/ml. Precision and accuracy, demonstrated by within-day, between-day assay, and interoperator assays were lower than 10%. 

Substrates other than mephenytoin which have caused clinical disturbances in people with deficient CYP2C19 alleles include omeprazol (41), proguanil (42), and citalopram (43). Additional substrates listed (8) include clomipramine, imipramine, diazepam, and propanolol. 

The metabolic activity of CYP2C19 has most frequently been probed, both in vivo and in vitro, using (5)-mephenytoin hydroxylation or mephenytoin SIR ratios. However, other substrates for this enzyme, including diazepam and imipramine, have been identified that have the potential to be used as probes (90,91). However, the most widely used identified CYP2C19 substrate is omeprazole (92). 

Andersson T, Cederberg C, Edvardsson G, et al. Effect of omeprazole treatment on diazepam plasma levels in slow versus normal rapid metabolizers of omeprazole. Clin Pharmacol Ther 1990 47 79-85. 

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