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Pharmacological advice for nefazodon, alprazolam and st. john's wort

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Summary Summary info 59%

Pharmacokinetic -3%
Nefazodon
Alprazolam
St. john's wort
Scores -14%
QT time prolongation
Anticholinergic effects
Serotonergic effects
Adverse drug events -24%
Somnolence
Sedation
Headache

Variants ✨

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medication Intended use

Explanations of the substances for patients

undefined Pharmacokinetics info -3%

∑ Exposureanefalpst.
Nefazodon n.a. 1 n.a.
Alprazolam 0.92 1.54 0.69
St. john's wort 1 1 1
Symbol (a): x-fold change in AUC
Legend (n.a.): Information not available

The changes in exposure mentioned relate to changes in the plasma concentration-time curve [AUC]. We did not detect any change in exposure to nefazodon, when combined with alprazolam (100%). We cannot currently estimate the influence of st. john's wort. We do not expect any change in exposure for st. john's wort, when combined with nefazodon (100%) and alprazolam (100%). Alprazolam exposure is reduced to 92%, when combined with nefazodon (154%) and st. john's wort (69%).

Rating: The pharmacokinetic parameters of the average population are used as the starting point for calculating the individual changes in exposure due to the interactions.
Nefazodon has a low oral bioavailability [ F ] of 20%, which is why the maximum plasma level [Cmax] tends to change strongly with an interaction. The protein binding [ Pb ] is very strong at 99%. The metabolism mainly takes place via CYP3A4.
Alprazolam has a high oral bioavailability [ F ] of 88%, which is why the maximum plasma levels [Cmax] tend to change little during an interaction. The terminal half-life [ t12 ] is 11.7 hours and constant plasma levels [ Css ] are reached after approximately 46.8 hours. The protein binding [ Pb ] is moderately strong at 70.2% and the volume of distribution [ Vd ] is 50 liters in the middle range, Since the substance has a low hepatic extraction rate of 0.04, displacement from protein binding [Pb] in the context of an interaction can increase exposure. The metabolism mainly takes place via CYP3A4.
The bioavailability, half-life, and volume of distribution of st. john's wort are unknown to us.

transmitter Serotonergic effects info -12%

Scores ∑ Points nefalpst.
Serotonergic Effects a 3++ Ø +
Symbol (a): Increased risk from 5 points. Please answer additional questions. See text.

Recommendation: The risk of a serotonergic syndrome is increased, but without an exact to the cognitive, vegative and neuromuscular symptoms we cannot make any recommendations for action at this time.

Rating: St. john's wort has a mild effect on the serotonergic system. Nefazodon modulates the serotonergic system to a moderate extent. According to our knowledge, alprazolam does not increase serotonergic activity.

transmitter Anticholinergic effects info -2%

Scores ∑ Points nefalpst.
Kiesel b 1Ø+Ø
Symbol (b): Increased risk from 3 points.

Recommendation: As a precaution, attention should be paid to anticholinergic symptoms, especially after increasing the dose and at doses in the upper therapeutic range.

Rating: Alprazolam only has a mild effect on the anticholinergic system. The risk of anticholinergic syndrome with this medication is rather low if the dosage is in the usual range. According to our findings, neither nefazodon nor st. john's wort increase anticholinergic activity.

electrocardiogram QT time prolongation info -0%

We do not know of any QT-prolonging potential for nefazodon, alprazolam and st. john's wort.

Other side effects General adverse effects info -24%

Side effects ∑ frequency nefalpst.
Somnolence61.9 %24.049.9n.a.
Sedation45.2 %n.a.45.2n.a.
Headache39.0 %39.0n.a.n.a.
Xerostomia34.3 %25.012.4n.a.
Dizziness33.9 %16.520.8n.a.
Fatigue31.3 %n.a.31.30.1
Constipation28.3 %13.517.1n.a.
Coordination problem24.8 %n.a.24.8n.a.
Memory impairment24.3 %n.a.24.3n.a.
Increased appetite19.9 %n.a.19.9n.a.
Tabular extract of the most common side effects
Sign (+): side effect described, but frequency not known
Sign (↑/↓): frequency rather higher / lower due to exposure

Gastrointestinal
Nausea (18.5%): nefazodon
Dyspepsis: st. john's wort

Neurological
Dysarthria (17.1%): alprazolam
Confusion (12.5%): alprazolam, nefazodon
Asthenia (10%): nefazodon
Seizure: nefazodon

Metabolic
Weight gain (14.9%): alprazolam

Mental
Depression (11.7%): alprazolam, nefazodon
Irritability: alprazolam
Rebound effect: alprazolam
Restlessness: st. john's wort
Addiction: alprazolam
Suicidal: nefazodon

Reproductive system
Reduced libido (10.2%): alprazolam
Priapism: nefazodon

Ophthalmological
Blurred vision (6%): nefazodon

Cardiac
Orthostatic hypotension (3.4%): nefazodon

Dermatological
Photosensitivity: st. john's wort
Stevens johnson syndrome: alprazolam, nefazodon

Hepatic
Liver failure: alprazolam, nefazodon
Hepatotoxicity: nefazodon

Hematological
Neutropenia: nefazodon

Immunological
Angioedema: nefazodon
Hypersensitivity reaction: nefazodon

Limitations Limitations

Based on your and scientific information, we assess the individual risk of undesirable side effects. The orange filled bars signal the basic potential of the drugs to cause this side effect. These recommendations are intended to advise professionals and are not a substitute for consultation with a doctor. In the restricted test version (alpha), the risk of all substances has not yet been conclusively assessed.

literature References

1. Fraser AD et al. Urinary screening for alprazolam and its major metabolites by the Abbott ADx and TDx analyzers with confirmation by GC/MS. Journal of analytical toxicology.
Authors: Fraser AD Bryan W Isner AF
Abstract: Alprazolam is a short-acting triazolobenzodiazepine with anxiolytic and antidepressant properties. It has a half-life of 10-15 hours after multiple oral doses. Approximately 20% of an oral dose is excreted unchanged in the urine. The major urinary metabolites are alpha-OH alprazolam glucuronide and 3-HMB benzophenone glucuronide. The objective of this study was to characterize the reactivity of alprazolam and three metabolites in the Abbott ADx and TDx urinary benzodiazepine assays compared with the EMIT d.a.u. benzodiazepine assay. Alprazolam (at 300 ng/mL) gave an equivalent response as the 300 ng/mL low control (nordiazepam). alpha-OH alprazolam gave an equivalent response to this control between 300-500 ng/mL and 4-OH alprazolam between 500-1000 ng/mL. The 3-HMB benzophenone was not positive even at 10,000 ng/mL. The ADx screening assay was positive in 26 of 31 urine specimens collected from alprazolam-treated patients. All 31 of these specimens were confirmed positive for alpha-OH alprazolam by GC/MS after enzymatic hydrolysis and formation of a TMS derivative. For the TDx, 27 of 31 specimens were positive for benzodiazepines and all 31 were confirmed by GC/MS. All 5 of the negative ADx specimens and 4 of 5 TDx specimens contained 150-400 ng/mL of alpha-OH alprazolam. In conclusion, both the ADx and TDx urine benzodiazepine assays are acceptable screening assays for alprazolam use when the alpha-OH alprazolam concentration is greater than 400 ng/mL.
Pubmed Id: 2046338
2. Fawcett JA et al. Alprazolam: pharmacokinetics, clinical efficacy, and mechanism of action. Pharmacotherapy.
Authors: Fawcett JA Kravitz HM
Abstract: Alprazolam, a triazolobenzodiazepine, is the first of this new class of benzodiazepine drugs to be marketed in the United States and Canada. It achieves peak serum levels in 0.7 to 2.1 hours and has a serum half-life of 12 to 15 hours. When given in the recommended daily dosage of 0.5 to 4.0 mg, it is as effective as diazepam and chlordiazepoxide as an anxiolytic agent. Its currently approved indication is for the treatment of anxiety disorders and symptoms of anxiety, including anxiety associated with depression. Although currently not approved for the treatment of depressive disorders, studies published to date have demonstrated that alprazolam compares favorably with standard tricyclic antidepressants. Also undergoing investigation is the potential role of alprazolam in the treatment of panic disorders. Alprazolam has been used in elderly patients with beneficial results and a low frequency of adverse reactions. Its primary side effect, drowsiness, is less than that produced by diazepam at comparable doses. Data on toxicity, tolerance, and withdrawal profile are limited, but alprazolam seems to be at least comparable to other benzodiazepines. Drug interaction data are also limited, and care should be exercised when prescribing alprazolam for patients taking other psychotropic drugs because of potential additive depressant effects.
Pubmed Id: 6133268
3. Smith RB et al. Pharmacokinetics and pharmacodynamics of alprazolam after oral and IV administration. Psychopharmacology. 1984
Authors: Smith RB Kroboth PD Vanderlugt JT Phillips JP Juhl RP
Abstract: Six fasting male subjects (20-32 years of age) received an oral tablet and an IV 1.0-mg dose of alprazolam in a crossover-design study. Alprazolam plasma concentration in multiple samples during 36 h after dosing was determined by electron-capture gas-liquid chromatography. Psychomotor performance tests, digit-symbol substitution (DSS), and perceptual speed (PS) were administered at 0, 1.25, 2.25, 5.0, and 12.5 h. Sedation was assessed by the subjects and by an observer using the Stanford Sleepiness Scale and a Nurse Rating Sedation Scale (NRSS), respectively. Mean kinetic parameters after IV and oral alprazolam were as follows: volume of distribution (Vd) 0.72 and 0.84 l/kg; elimination half-life (t1/2) 11.7 and 11.8 h; clearance (Cl) 0.74 and 0.89 ml/min/kg. There were no significant differences between IV and oral alprazolam in Vd, t1/2, or area under the curve. The mean fraction absorbed after oral administration was 0.92. Performance on PS and DSS tests was impaired at 1.25 and 2.5 h, but had returned to baseline at 5.0 h for both treatments. Onset of sedation was rapid after IV administration and the average time of peak sedation was 0.48 h. Sedation scores were significantly lower during hour 1 after oral administration than after IV, but were not significantly different at later times. Alprazolam is fully available after oral administration and kinetic parameters are not affected by route of administration. With the exception of rapidity of onset, the pharmacodynamic profiles of IV and oral alprazolam are very similar after a 1.0-mg dose.
Pubmed Id: 6152055
4. Greene DS et al. Clinical pharmacokinetics of nefazodone. Clinical pharmacokinetics. 1997
Authors: Greene DS Barbhaiya RH
Abstract: Nefazodone is a new antidepressant drug, chemically unrelated to the tricyclic, tetracyclic or selective serotonin uptake inhibitors. Nefazodone blocks the serotonin 5-HT2 receptors and reversibly inhibits serotonin reuptake in vivo. Nefazodone is completely and rapidly absorbed after oral administration with a peak plasma concentration observed within 2 hours of administration. Nefazodone undergoes significant first-pass metabolism resulting in an oral bioavailability of approximately 20%. Although there is an 18% increase in nefazodone bioavailability with food, this increase is not clinically significant and nefazodone can be administered without regard to meals. Three pharmacologically active nefazodone metabolites have been identified: hydroxy-nefazodone, triazoledione and m-chlorophenylpiperazine (mCPP). The pharmacokinetics of nefazodone are nonlinear. The increase in plasma concentrations of nefazodone are greater than would be expected if they were proportional to increases in dose. Steady-state plasma concentrations of nefazodone are attained within 4 days of the commencement of administration. The pharmacokinetics of nefazodone are not appreciably altered in patients with renal or mild-to-moderate hepatic impairment. However, nefazodone plasma concentrations are increased in severe hepatic impairment and in the elderly, especially in elderly females. Lower doses of nefazodone may be necessary in these groups. Nefazodone is a weak inhibitor of cytochrome P450 (CYP) 2D6 and does not inhibit CYP1A2. It is not anticipated that nefazodone will interact with drugs cleared by these isozymes. Indeed, nefazodone did not affect the pharmacokinetics of theophylline, a compound cleared by CYP1A2. Nefazodone is metabolised by and inhibits CYP3A4. Clinically significant interactions have been observed between nefazodone and the benzodiazepines triazolam and alprazolam, cyclosporin and carbamazepine. The potential for a clinically significant interaction between nefazodone and other drugs cleared by CYP3A4 (e.g. terfenadine) should be considered before the coadministration of these compounds. There was an increase in haloperidol plasma concentrations when coadministered with nefazodone; nefazodone pharmacokinetics were not affected after coadministration. No clinically significant interaction was observed when nefazodone was administered with lorazepam, lithium, alcohol, cimetidine, warfarin, theophylline or propranolol.
Pubmed Id: 9342502
5. Rotzinger S et al. Human CYP3A4 and the metabolism of nefazodone and hydroxynefazodone by human liver microsomes and heterologously expressed enzymes. European neuropsychopharmacology : the journal of the European College of Neuropsychopharmacology. 2002
Authors: Rotzinger S Baker GB
Abstract: Nefazodone is an antidepressant with a relatively unique structure and mechanism of action. The current study was conducted to assess the potential for nefazodone to have metabolic drug interactions associated with cytochrome P450 (CYP) enzymes. Nefazodone is metabolised to hydroxynefazodone (OH-NEF), triazoledione (TD), and m-chlorophenylpiperazine (m-CPP), and OH-NEF is metabolised to TD and m-CPP. Correlations with enzyme activities in a panel of microsomes prepared from human livers, incubations with heterologously expressed human CYP enzymes, and incubations with enzyme inhibitors were used to study these metabolic pathways. The results suggest that the metabolism of NEF and OH-NEF to each of their active metabolites is catalysed mainly by CYP3A4, which is in agreement with clinical reports of drug--drug interactions of nefazodone with substrates and inhibitors of CYP3A4.
Pubmed Id: 11872324
6. Dannawi M Possible serotonin syndrome after combination of buspirone and St John's Wort. Journal of psychopharmacology (Oxford, England). 2002
Authors: Dannawi M
Abstract: No Abstract available
Pubmed Id: 12503845
7. Park JY et al. Effect of CYP3A5*3 genotype on the pharmacokinetics and pharmacodynamics of alprazolam in healthy subjects. Clinical pharmacology and therapeutics. 2006
Authors: Park JY Kim KA Park PW Lee OJ Kang DK Shon JH Liu KH Shin JG
Abstract: OBJECTIVE: Our objective was to evaluate the effect of the CYP3A5 genotype on the pharmacokinetics and pharmacodynamics of alprazolam in healthy volunteers. METHODS: Nineteen healthy male volunteers were divided into 3 groups on the basis of the genetic polymorphism of CYP3A5. The groups comprised subjects with CYP3A5*1/*1 (n=5), CYP3A5*1/*3 (n=7), or CYP3A5*3/*3 (n=7). After a single oral 1-mg dose of alprazolam, plasma concentrations of alprazolam were measured up to 72 hours, together with assessment of psychomotor function by use of the Digit Symbol Substitution Test, according to CYP3A5 genotype. RESULTS: The area under the plasma concentration-time curve for alprazolam was significantly greater in subjects with CYP3A5*3/*3 (830.5+/-160.4 ng . h/mL [mean+/-SD]) than in those with CYP3A5*1/*1 (599.9+/-141.0 ng . h/mL) (P=.030). The oral clearance of alprazolam was also significantly different between the CYP3A5*1/*1 group (3.5+/-0.8 L/h) and CYP3A5*3/*3 group (2.5+/-0.5 L/h) (P=.036). Although a trend was noted for the area under the Digit Symbol Substitution Test score change-time curve (area under the effect curve) to be greater in subjects with CYP3A5*3/*3 (177.2+/-84.6) than in those with CYP3A5*1/*1 (107.5+/-44), the difference did not reach statistical significance (P=.148). CONCLUSIONS: The CYP3A5*3 genotype affects the disposition of alprazolam and thus influences the plasma levels of alprazolam.
Pubmed Id: 16765147
8. Kiesel EK et al. An anticholinergic burden score for German prescribers: score development. BMC geriatrics. 2018
Authors: Kiesel EK Hopf YM Drey M
Abstract: BACKGROUND: Anticholinergic drugs put elderly patients at a higher risk for falls, cognitive decline, and delirium as well as peripheral adverse reactions like dry mouth or constipation. Prescribers are often unaware of the drug-based anticholinergic burden (ACB) of their patients. This study aimed to develop an anticholinergic burden score for drugs licensed in Germany to be used by clinicians at prescribing level. METHODS: A systematic literature search in pubmed assessed previously published ACB tools. Quantitative grading scores were extracted, reduced to drugs available in Germany, and reevaluated by expert discussion. Drugs were scored as having no, weak, moderate, or strong anticholinergic effects. Further drugs were identified in clinical routine and included as well. RESULTS: The literature search identified 692 different drugs, with 548 drugs available in Germany. After exclusion of drugs due to no systemic effect or scoring of drug combinations (n = 67) and evaluation of 26 additional identified drugs in clinical routine, 504 drugs were scored. Of those, 356 drugs were categorised as having no, 104 drugs were scored as weak, 18 as moderate and 29 as having strong anticholinergic effects. CONCLUSIONS: The newly created ACB score for drugs authorized in Germany can be used in daily clinical practice to reduce potentially inappropriate medications for elderly patients. Further clinical studies investigating its effect on reducing anticholinergic side effects are necessary for validation.
Pubmed Id: 30305048

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