Triazolam ketoconazole

Triazolam is distributed quickly because of its high lipophilicity, and thus it has a short duration of effect. Erythromycin, nefazodone, fluvoxamine, and ketoconazole reduce the clearance of triazolam and increase plasma concentrations. 

Concurrent use with ketoconazole, itraconazole, and nefazodone, medications that significantly impair the oxidative metabolism of triazolam mediated by cytochrome P-450 3A (CYP3A). 

Hypersensitivity to ketoconazole. Do not use ketoconazole for the treatment of fungal meningitis because it penetrates poorly into the CSF. Concomitant administration of ketoconazole with oral triazolam is contraindicated. 

Drugs that might be affected by lopinavir/ritonavir include ergot derivatives, oral contraceptives, antiarrhythmics, HMG-CoA reductase inhibitors, HIV protease inhibitors, atovaquone, calcium channel blockers, ketoconazole, itraconazole, pimozide, cisapride, clarithromycin, disulfiram, metronidazole, immunosuppressants, midazolam, triazolam, narcotic analgesics, rifabutin and rifabutin metabolite, sildenafil, warfarin, bupropion, clozapine, desipramine, piroxicam, quinidine, theophylline, and zolpidem. 

Aprepitant (Emend) [Centrally Acting Antiemetic] Uses Pre-vents N/V assoc w/ emetogenic CA chemo (eg, cisplatin) (use in combo w/ other antiemetics) Action Substance P/neurokinin l(NKi) receptor antagonist Dose 125 mg PO day 1, 1 h before chemo, then 80 mg PO qAM days 2 3 Caution [B, /-] Contra Use w/ pimozide, Disp Caps SE Fatigue, asthenia, hiccups Interactions T Effects W/ clarithromycin, diltiazem, itraconazole, ketoconazole, nefazodone, nelfinavir, ritonavir, troleandomycin T effects OF alprazolam, astem-izole, cisapride, dexamethasone, methylprednisolone, midazolam, pimozide, terfe-nadine, triazolam, chemo agents, eg, docetaxel, etoposide, ifosfamide, imatinib, irinotecan, paclitaxel, vinblastine, vincristine, vinorelbine i effects W/ paroxetine,... 

Like fluoxetine, erythromycin and other macrolides inhibit the CYP-3A isoenzyme and increase the levels and effects of the triazolobenzodiazepines (Shader and Greenblatt, 1995 Chouinard et ah, 1999). Midazolam should be avoided or the dosage dropped by 50% in patients receiving erythromycin (Olkkola et ah, 1993). Ketoconazole and itraconazole may also interact with triazolam and midazolam, and combinations of these drugs should be avoided (Varhe et ah, 1994 Chouinard et ah, 1999). 

Varhe, A., Olkkolam, K.T., and Neuvonen, P.J. (1994) Pharmacokinetics and drug disposion oral triazolam is potentially hazardous to patients receiving systemic antimycotics ketoconazole or itraconazole. Clin Pharmacol Ther 56 601—607. 

BZD hypnotics such as midazolam and triazolam are primarily metabolized via the P450 3A3/4 microenzyme system. Other BZDs often used as hypnotics, such as diazepam, can also be metabolized by CYP 33/4 and CYP 2C19. Any drugs that act as inhibitors or inducers of these isoenzymes could increase or decrease BZD levels, respectively (350). Thus, ketoconazole, macrolide antibiotics (e.g., erythromycin), SSRIs (e.g., fluoxetine-norfluoxetine and fluvoxamine), and other antidepressants (especially nefazodone) may decrease clearance and increase BZD levels to potentially toxic ranges. Conversely, rifampacin, CBZ, and dexamethasone may increase clearance and decrease BZD levels to potentially subtherapeutic ranges. 

T effects OF amiodarone, astemizole, atorvastadn, barbiturates, bepridil, bupropion, cerivastatin, cisapride, clorazepate, clozapine, clarithromycin, desipramine, diazepam, encainide, ergot alkaloids, estazolam, flecainide, flurazepam, indinavir, ketoconazole, lovastatin, meperidine, midazolam, nelfinavir, phenytoin, pimozide, piroxicam, propafenone, propoxyphene, quinidine, rifabutin, saquinavir, sildenafil, simvastatin, SSRIs, TCAs, terfenadine, triazolam, troleandomycin, zolpidem X effects W/ barbiturates, carbamazepine, phenytoin, rifabutin, rifampin, St. John s wort, tobacco X effects OF didanosine, hypnotics, methadone, OCPs, sedatives, theophylline, warfarin EMS T Effects of amiodarone, diazepam, midazolam and BBs, may need X- doses concurrent use of Viagra-type drugs can lead to hypotension X- effects of warfarin concurrent EtOH use can T adverse effects T glucose ODs May cause an extension of adverse SEs symptomatic and supportive Rivasrigmine (Exelon) [Cholinesterase Inhibitor/Anri ... 

The intrinsic kinetic properties of the victim drug also influence the potential clinical consequences of an interaction. For orally administered medications that undergo significant presystemic extraction, impairment of clearance by a CYP inhibitor may produce increases in bioavailability (reduced presystemic extraction) as a consequence of reduced clearance. The effects may be particularly dramatic for CYP3A substrates (such as triazolam, midazolam, or buspirone) that undergo both hepatic and enteric presystemic extraction. As an example, coadministration of the CYP3A inhibitor ketoconazole with triazolam produced very large increases in area under the plasma concentration-time curve... 

Figure 2 Mean ( SE) plasma concentrations of triazolam (left) or alprazolam (right) in a series of healthy individuals who participated in a clinical pharmacokinetic study. In one phase of the study, they ingested a single 0.25-mg oral dose of triazolam with ketoco-nazole, 200 mg twice daily, or with placebo to match ketoconazole (control). In the second phase of the study, they took 1.0 mg of alprazolam orally, either with the same dosage of ketoconazole or with placebo to match ketoconazole (control). Note that ketoconazole increases AUC and reduces clearance of both triazolam and alprazolam. For triazolam (a high-extraction compound), the effect is evident as reduced presystemic extraction, increased Cmax, and prolonged half-life. However, for alprazolam (a low-extraction compound), the effect of ketoconazole is evident only as a prolongation of half-life. Abbreviation AUC, the plasma concentration-time curve. Source Adapted, in part, from Ref. 74.

AUC) and increases in peak plasma concentration (Cmax) of triazolam (73,74) (Fig. 2). Cotreatment of ketoconazole with alprazolam, also a CYP3A substrate, produced a large increase in AUC for alprazolam (74). However, alprazolam is a low-extraction compound with bioavailability ordinarily in the range of 90% (75). As such, the reduction in alprazolam clearance caused by ketoconazole was evident mainly as prolonged elimination half-life but without a significant change in Cmax. 

Fahey JM, Pritchard GA, von Moltke LL, et al. The effects of ketoconazole on triazolam pharmacokinetics, pharmacodynamics and benzodiazepine receptor binding in mice. J Pharmacol Exp Ther 1998 285 271-276. 

Greenblatt DJ, Wright CE, von Moltke LL, et al. Ketoconazole inhibition of triazolam and alprazolam clearance differential kinetic and dynamic consequences. Clin Pharmacol Ther 1998 64 237-247. 

A4/3A5 Midazolam, buspirone, felodipine, lovastatin, eletriptan, sildenafil, simvastatin, triazolam Atazanavir, clarithromycin, indinavir, itraconazole, ketoconazole, nefazodone, nelfinavir, ritonavir, saquinavir, telithromycin Rifampin, carbamazepine... 

In a double-blind, crossover, pharmacokinetic and pharmacodynamic study of the interaction of ketoconazole with alprazolam and triazolam, two CYP3A4 substrate drugs with different kinetic profiles, impaired clearance by ketoconazole had more profound clinical consequences for triazolam than for alprazolam (39). 

Ketoconazole can increase the concentrations of triazolam through inhibition of CYP3A4 (18). 

If erythromycin, also a CYP3A4 inhibitor, is given in combination with ketoconazole, there is an even more dramatic effect on triazolam concentrations. 

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