Determination of alpha-naphthylisothiocyanate and metabolites alpha-naphthylamine and alpha-naphthylisocyanate in rat plasma and urine by high-performance liquid chromatography

A rapid and sensitive high-performance liquid chromatographic (HPLC) assay for the determination of alpha-naphthylisothiocyanate (1-NITC) and two metabolites alpha-naphthylamine (1-NA) and alpha-naphthylisocyanate (1-NIC) in rat plasma and urine has been developed. The chromatographic analysis was carried out using reversed-phase isocratic elution with a Partisphere C(18) 5-microm column, a mobile phase of acetonitrile-water (ACN-H(2)O 70:30, v/v), and detection by ultraviolet (UV) absorption at 305 nm. The lower limits of quantitation (LLQ) in rat plasma, urine, and ACN were 10, 30, and 10 ng/ml for 1-NITC; 30, 100, and 30 ng/ml for 1-NA; and 30 ng/ml in ACN for 1-NIC. At low (10 ng/ml), medium (500 ng/ml), and high (5000 ng/ml) concentrations of quality control samples (QCs), the range of within-day and between-day accuracies were 95-106 and 97-103% for 1-NITC in plasma, respectively. Stability studies showed that 1-NITC was stable at all tested temperatures in ACN, and at -20 and -80 degrees C in plasma, urine, and ACN precipitated plasma and urine, but degraded at room temperature and 4 degrees C. 1-NA was stable in all of the tested matrices at all temperatures. 1-NIC was unstable in plasma, urine, and ACN precipitated plasma and urine, but stable in ACN. The degradation product of 1-NITC and 1-NIC in universal buffer was confirmed to be 1-NA. 1-NITC and 1-NA were detected and quantified in rat plasma and urine, following the administration of a 25 mg/kg i.v. dose of 1-NITC to a female Sprague-Dawley rat.

On-line fluorescence determination of pressure mediated outer membrane damage in Escherichia coli

The outer membrane (OM) of Gram-negative bacteria provides a protective barrier for natural occurring inhibitors. Pressure mediated OM permeabilisation therefore contributes to the elimination of Escherichia coli and Salmonella by pressure preservation processes. Pressure mediated inactivation, sublethal injury, and membrane permeabilisation of E. coli were determined using two strains differing in their barotolerance. Pressure treatment of E. coli TMW 2.427 at 300, 500 and 600 MPa for 40 min resulted in a 0, 1, and greater 6 log decrease of viable cell counts, respectively. The kinetics of OM and cytoplasmic membrane permeabilisation after pressure treatment were determined by staining of pressure treated cells with the fluorescent dyes propidium iodide (PI) and 1-N-phenylnaphtylamine (NPN), respectively. A slight increase of PI fluorescence was observed at conditions resulting in a greater 6 log decrease of viable cell counts only. In contrast, increased NPN fluorescence indicating OM permeabilisation was observed prior to cell death and sublethal injury. An on-line assay for determination of pressure mediated OM damage based on NPN fluorescence was established to distinguish between reversible and irreversible OM damage. Generally, the same degree of outer membrane damage was observed by either on line or off line determinations. However, whereas reversible membrane damage occurred fast and in thermodynamic equilibrium with pressure conditions, irreversible outer membrane damage was a time dependent process.

Selective serotonin reuptake inhibitor discontinuation syndrome: a randomized clinical trial

BACKGROUND

Recent reports describe discontinuation-emergent adverse events upon cessation of selective serotonin reuptake inhibitors including dizziness, insomnia, nervousness, nausea, and agitation. We hypothesized that interruption of fluoxetine treatment would be associated with fewer discontinuation-emergent adverse events than interruption of sertraline or paroxetine treatment, based on fluoxetine's longer half-life.

METHODS

In this 4-week study, 242 patients with remitted depression receiving maintenance therapy with open-label fluoxetine, sertraline, or paroxetine for 4-24 months had their maintenance therapy interrupted with double-blind placebo substitution for 5-8 days. The Symptom Questionnaire (SQ), the Discontinuation-Emergent Signs and Symptoms checklist, the 28-item Hamilton Depression Rating Scale, and the Montgomery-Asberg Depression Rating Scale were used to assess somatic distress and stability of antidepressant response.

RESULTS

Two hundred twenty patients (91%) completed the study. Following interruption of therapy, fluoxetine-treated patients experienced fewer discontinuation-emergent events than either sertraline-treated or paroxetine-treated patients (p < .001). The mean SQ somatic symptom scale score in fluoxetine-treated patients was significantly lower than that in sertraline-treated and paroxetine-treated patients (p < .001). Fluoxetine-treated patients also experienced less reemergence of depressive symptoms than sertraline-treated or paroxetine-treated patients (p < .001).

CONCLUSIONS

Abrupt interruption of antidepressant therapy for 5-8 days was associated with the emergence of new somatic and psychological symptoms in patients treated with paroxetine and to a lesser degree sertraline, with few symptoms seen with fluoxetine.

Simultaneous determination of human plasma levels of citalopram, paroxetine, sertraline, and their metabolites by gas chromatography-mass spectrometry

A gas chromatography-mass spectrometry method is presented which allows the simultaneous determination of the plasma concentrations of the selective serotonin reuptake inhibitors citalopram, paroxetine, sertraline, and their pharmacologically active N-demethylated metabolites (desmethylcitalopram, didesmethylcitalopram, and desmethylsertraline) after derivatization with the reagent N-methyl-bis(trifluoroacetamide). No interferences from endogenous compounds are observed following the extraction of plasma samples from six different human subjects. The standard curves are linear over a working range of 10-500 ng/mL for citalopram, 10-300 ng/mL for desmethylcitalopram, 5-60 ng/mL for didesmethylcitalopram, 20-400 ng/mL for sertraline and desmethylsertraline, and 10-200 ng/mL for paroxetine. Recoveries measured at three concentrations range from 81 to 118% for the tertiary amines (citalopram and the internal standard methylmaprotiline), 73 to 95% for the secondary amines (desmethylcitalopram, paroxetine and sertraline), and 39 to 66% for the primary amines (didesmethylcitalopram and desmethylsertraline). Intra- and interday coefficients of variation determined at three concentrations range from 3 to 11% for citalopram and its metabolites, 4 to 15% for paroxetine, and 5 to 13% for sertraline and desmethylsertraline. The limits of quantitation of the method are 2 ng/mL for citalopram and paroxetine, 1 ng/mL for sertraline, and 0.5 ng/mL for desmethylcitalopram, didesmethylcitalopram, and desmethylsertraline. No interferences are noted from 20 other psychotropic drugs. This sensitive and specific method can be used for single-dose pharmacokinetics. It is also useful for therapeutic drug monitoring of these three drugs and could possibly be adapted for the quantitation of the two other selective serotonin reuptake inhibitors on the market, namely fluoxetine and fluvoxamine.

Yersinia pseudotuberculosis and Yersinia pestis show increased outer membrane permeability to hydrophobic agents which correlates with lipopolysaccharide acyl-chain fluidity

The hydrophobic probe N-phenyl-1-naphthylamine accumulated less in non-pathogenic Yersinia spp. and non-pathogenic and pathogenic Yersinia enterocolitica than in Yersinia pseudotuberculosis or Yersinia pestis. This was largely due to differences in the activity of efflux systems, but also to differences in outer membrane permeability because uptake of the probe in KCN/arsenate-poisoned cells was slower in the former group than in Y. pseudotuberculosis and Y. pestis. The probe accumulation rate was higher in Y. pseudotuberculosis and Y. pestis grown at 37 degrees C than at 26 degrees C and was always highest in Y. pestis. These yersiniae had LPSs with shorter polysaccharides than Y. enterocolitica, particularly when grown at 37 degrees C. Gel<-->liquid-crystalline phase transitions (Tc 28-31 degrees C) were observed in LPS aggregates of Y. enterocolitica grown at 26 and 37 degrees C, with no differences between non-pathogenic and pathogenic strains. Y. pseudotuberculosis and Y. pestis LPSs showed no phase transitions and, although the fluidity of LPSs of Y. pseudotuberculosis and Y. enterocolitica grown at 26 degrees C were close below the Tc of the latter, they were always in a more fluid state than Y. enterocolitica LPS. Comparison with previous studies of Salmonella choleraesuis subsp. choleraesuis serotype minnesota rough LPS showed that the increased fluidity and absence of transition of Y. pseudotuberculosis and Y. pestis LPSs cannot be explained by their shorter polysaccharides and suggested differences at the lipid A/core level. It is proposed that differences in LPS-LPS interactions and efflux activity explain the above observations and reflect the adaptation of Yersinia spp. to different habitats.

Distribution and excretion of sertraline and N-desmethylsertraline in human milk

AIMS

To characterise milk/plasma (M/P) ratio and infant exposure, for sertraline and N-desmethylsertraline, in breast-feeding women taking sertraline for the treatment of depression.

METHODS

Eight women (mean age 28 years) taking sertraline (1.05 mg kg(-1) day(-1)) and their infants (mean age 5.7 months) were studied. Sertraline and N-desmethylsertraline in plasma and milk were measured by high-performance liquid chromatography over a 24 h dose interval at steady-state. M/P values were estimated from area under the plasma and milk concentration-time curves. All milk produced was collected over the dose interval. Infant exposure was estimated as the product of actual or estimated milk production, and average drug concentration in milk, normalized to body weight and expressed as a percentage of the weight-adjusted maternal dose.

RESULTS

Mean milk production was 321 ml day(-1) (range 34-974 ml). Mean M/P values of 1.93 and 1.64 were calculated for sertraline and N-desmethylsertraline respectively. Infant exposure estimated from actual milk produced was 0.2% and 0.3% of the weight-adjusted maternal dose for sertraline and N-desmethylsertraline (as sertraline equivalents) respectively. When calculated from estimated milk production (0.15 l kg(-1) day(-1)), infant exposure was significantly greater (P<0.0001) at 0.90% and 1.32% for sertraline and N-desmethylsertraline respectively. Neither sertraline nor its N-desmethyl metabolite could be detected in plasma samples from the four infants tested. No adverse effects were observed in any of the eight infants and all had achieved normal developmental milestones.

CONCLUSIONS

Irrespective of the method of calculation of infant exposure, the mean total dose of sertraline and its N-desmethyl metabolite transmitted to infants via breast-feeding is low and unlikely to cause any significant adverse effects.

Lamotrigine toxicity secondary to sertraline

Blood level monitoring helps to determine the therapeutic and toxic ranges for anticonvulsants and antidepressants. We investigated initial drug-drug interactions between lamotrigine and sertraline. We report on case histories of two epileptic patients who were initially on lamotrigine and to whom sertraline was added to control psychiatric features. In case 1, a total daily dose of 25 mg sertraline, with nondetectable sertraline and desmethylsertraline blood levels, resulted in a doubling of the lamotrigine blood level with symptoms of toxicity. In case 2, a 25 mg reduction in the total daily dose of sertraline resulted in halving of the lamotrigine blood level even though the lamotrigine dosage was increased by 33%. This shows that sertraline has potent interactions with lamotrigine metabolism. The authors hypothesize that inhibition of glucuronidation is responsible. Clinicians are advised to observe for symptoms of toxicity and to do serial blood levels to monitor this interaction.

Sertraline treatment of children and adolescents with obsessive-compulsive disorder or depression: pharmacokinetics, tolerability, and efficacy

OBJECTIVE

To evaluate the pharmacokinetics, safety, and efficacy of sertraline in children (6 to 12 years old) and adolescents (13 to 17 years old).

METHOD

Children (n = 29) and adolescents (n = 32) with major depression, obsessive-compulsive disorder (OCD), or both received a single dose of 50 mg of sertraline followed, 1 week later, by 35 days of sertraline treatment as follows: (1) either a starting dose of 25 mg/day titrated to 200 mg/day in 25-mg increments or (2) a starting dose of 50 mg/day titrated to 200 mg/day in 50-mg increments. Sertraline and desmethylsertraline pharmacokinetics were determined approximately weekly, and efficacy measures were assessed before drug administration and at the end of treatment.

RESULTS

Mean area under the plasma concentration-time curve (AUC), peak plasma concentration (Cmax), and elimination half-life (t1/2) for sertraline and desmethylsertraline were similar to previously reported adult values. No titration-dependent pharmacokinetic or safety differences were seen. While Cmax and AUC0-24 were greater for children versus adolescents, these differences disappeared after parameters were normalized for body weight. Sertraline was well tolerated in both children and adolescents, with adverse experiences similar to those previously reported by adult patients. Efficacy measurements indicated improvement (p < .001) in depression and OCD symptomatology.

CONCLUSIONS

Sertraline can be safely administered to pediatric patients using the currently recommended adult titration schedule.

Black and white patients response to antidepressant treatment for major depression

Differences in response to psychopharmacologic agents according to race has so far primarily focused on investigations related to the response of Asian-American patients to neuroleptics and lithium. In this article, we present evidence which depicts that black patients need lower doses of tricyclic antidepressants (TCAs) than white patients to attain a similar response in the treatment of major depression. Likewise, we also advance that black patients might need lower doses of selective serotonin re-uptake inhibitor antidepressants (SSRIs) than white patients to attain a similar response in the treatment of major depression. Further studies are suggested to confirm these findings.

Sertraline in diabetic neuropathy: preliminary results

Previous research has shown that antidepressants have been useful in the treatment of pain, particularly diabetic neuropathy. This study was an initial open investigation into the use of sertraline in diabetic neuropathy. Eight patients with diabetic neuropathy but not depression were treated with increasing doses of sertraline to a maximum of 150 mg/day for 8 weeks. Sertraline treatment led to significant reductions in mean visual analog scale (VAS) ratings, e.g., pain from 71.2 to 23.1 (t = 3.74, p < .01) and paresthesias from 53.8 to 15.0 (t = 4.15, p < .01). Baseline platelet serotonin (5HT) content also correlated significantly with improvement in pain (r = 0.70,p =. 05). Plasma sertraline (SRT) correlated with improvement in paresthesias (r = 0.70).

CONCLUSION

This preliminary result indicates the potential application of sertraline to treatment of diabetic neuropathy. A replication is now underway.

Effect of sertraline on plasma nortriptyline levels in depressed elderly

BACKGROUND

Several serotonin selective reuptake inhibitors have been reported to be inhibitors of the cytochrome P450 2D6 (CYP2D6). Thus, they may increase the plasma level of secondary amine tricyclic antidepressants, which are predominantly metabolized through this enzyme. Except for a few case reports, no clinical data document the degree of this drug-drug interaction in elderly depressed patients.

METHOD

We systematically examined this interaction by determining the change in plasma nortriptyline levels in 14 elderly depressed patients in whom sertraline was added to nortriptyline.

RESULTS

After addition of 50 mg/day of sertraline, the median increase in plasma nortriptyline level over baseline was 2% (range, -26% to 117%; p = .30). In 2 patients (14%), there was an increase of 50% or more. For patients taking higher sertraline doses (N = 7; 100 or 150 mg/day), the median increase in plasma nortriptyline level over baseline was 40% (range, -12% to 239%; p = .08).

CONCLUSION

Overall, a modest effect of sertraline was observed on nortriptyline metabolism in these elderly depressed patients. This is consistent with prior reports of a weak inhibition of CYP2D6 by sertraline in vitro and in young healthy volunteers. However, some patients showed a change in plasma nortriptyline level that would be considered clinically significant. Thus, careful monitoring of plasma nortriptyline levels is recommended in all patients treated with a combination of nortriptyline and sertraline.

Polyethyleneimine is an effective permeabilizer of gram-negative bacteria

The effect of the polycation polyethyleneimine (PEI) on the permeability properties of the Gram-negative bacterial outer membrane was investigated using Escherichia coli, Pseudomonas aeruginosa and Salmonella typhimurium as target organisms. At concentrations of less than 20 micrograms ml-1, PEI increased the bacterial uptake of 1-N-phenylnaphthylamine, which is a hydrophobic probe whose quantum yield is greatly increased in a lipid environment, indicating increased hydrophobic permeation of the outer membrane by PEI. The effect of PEI was comparable to that brought about by the well-known permeabilizer EDTA. Permeabilization by PEI was retarded but not completely inhibited by millimolar concentrations of MgCl2. PEI also increased the susceptibility of the test species to the hydrophobic antibiotics clindamycin, erythromycin, fucidin, novobiocin and rifampicin, without being directly bactericidal. PEI sensitized the bacteria to the lytic action of the detergent SDS in assays where the bacteria were pretreated with PEI. In assays where PEI and SDS were simultaneously present, no sensitization was observed, indicating that PEI and SDS were inactivating each other. In addition, a sensitizing effect to the nonionic detergent Triton X-100 was observed for P. aeruginosa. In conclusion, PEI was shown to be a potent permeabilizer of the outer membrane of Gram-negative bacteria.

Sertraline and desmethylsertraline in human breast milk and nursing infants

OBJECTIVE

The purpose of this study was to determine the concentrations of sertraline and desmethylsertraline in both human breast milk and infant serum.

METHOD

Breast milk samples from 12 women were collected at specific time intervals after oral doses of sertraline (25-200 mg once daily). For 11 mother-infant pairs, maternal serum levels 24 hours after a dose and their infants' serum levels 2-4 hours after nursing were ascertained by high-performance liquid chromatography.

RESULTS

Sertraline and desmethylsertraline were present in all breast milk samples, with a gradient from "fore" milk to "hind" milk. The highest concentrations of sertraline were observed in hind milk 7-10 hours after maternal dose. Increasing the maternal dose of sertraline resulted in increased breast milk concentrations of both sertraline and desmethylsertraline. Detectable concentrations of sertraline were found in three nursing infants and desmethylsertraline in six. No adverse effects of exposure were observed in any infant.

CONCLUSIONS

Sertraline and desmethylsertraline were present in the breast milk of nursing women treated with sertraline. Concentrations were affected by aliquot of milk sampled, time after maternal dose, and maternal daily dose. The infants' serum concentrations detected were below the detection limit of most commercial laboratories. The presence of desmethylsertraline in six infants' samples underscores the importance of metabolite monitoring in determining infant exposure. Estimates of daily infant exposure can be determined after analysis of sertraline and desmethylsertraline concentrations from one full breast at maternal serum steady state. Future studies of breast milk and infant serum samples should address these issues.

Pharmacokinetic drug interactions of new antidepressants: a review of the effects on the metabolism of other drugs

Seven of the newest antidepressants are the serotonin-selective reuptake inhibitors (fluoxetine, sertraline, paroxetine, and fluvoxamine [currently approved in the United States only for obsessive-compulsive disorder]), a serotonin-norepinephrine reuptake inhibitor (venlafaxine), a postsynaptic serotonin antagonist-presynaptic serotonin reuptake inhibitor (nefazodone), and a presynaptic-postsynaptic noradrenergic-serotonergic receptor antagonist (mirtazapine). Many of these drugs are potent inhibitors of the cytochrome P-450 enzymes (CYPs) of the liver. The isoforms of the CYPs most relevant to the use of antidepressants are CYP1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A4. CYP inhibition may affect the metabolism of numerous drugs in several classes that are substrates for these isoenzymes, with potentially serious consequences. To minimize the potential for an adverse event, the practitioner must remember the drug-drug interactions, and possible consequences when one of these antidepressants is being prescribed. A "primer" on drug metabolism is included herein, which serves as a basis for understanding these interactions., Each of the isoenzymes of the CYPs is discussed in relationship to the drugs they metabolize, and appropriate cautions are recommended for concurrent administration of these new antidepressants and other drugs most frequently prescribed to elderly patients.

Desipramine pharmacokinetics when coadministered with paroxetine or sertraline in extensive metabolizers

In vitro studies have shown that fluoxetine and paroxetine are more potent inhibitors of cytochrome CYP2D6 than sertraline. The pharmacokinetics of desipramine when coadministered with the selective serotonin reuptake inhibitors (SSRIs) paroxetine and sertraline were studied in 24 healthy male volunteers (CYP2D6 extensive metabolizers). Desipramine (50 mg/day) was administered for 23 days in each phase of the crossover study with a 7-day drug-free period between phases. In addition, subjects were randomly assigned to receive concomitant paroxetine (20 mg/day on days 8 through 17 followed by 30 mg/day on days 18 through 20) or sertraline (50 mg/day on days 8 through 17 and 100 mg/day on days 18 through 20). SSRI treatments were switched between phases. After 10 days of coadministration at the lower dose, mean desipramine maximum concentration in plasma (Cmax) relative to baseline increased from 37.8 to 173 ng/mL (+358%) with paroxetine versus from 36.1 to 51.9 ng/mL (+44%) with sertraline; the mean desipramine 24-hour area under the concentration-time curve (AUC[24]) increased from 634 to 3,305 ng x h/mL (+421%) with paroxetine versus from 611 to 838 ng x h/mL (+37%) with sertraline; and the mean desipramine trough value (C0) increased from 18.5 to 113 ng/mL (+511%) with paroxetine versus from 18.3 to 21.8 ng/mL (+19%) with sertraline (all increases, p < 0.001). An approximately 10-fold increase in the Cmax and AUC(24) of paroxetine and an approximately 2-fold increase in these parameters for sertraline occurred simultaneously with the desipramine concentration changes. Thus, when coadministered with 50 mg/day desipramine, sertraline had significantly less pharmacokinetic interaction than paroxetine with desipramine at the recommended starting dosages of 50 mg/day and 20 mg/day, respectively.

Venlafaxine: in vitro inhibition of CYP2D6 dependent imipramine and desipramine metabolism; comparative studies with selected SSRIs, and effects on human hepatic CYP3A4, CYP2C9 and CYP1A2

AIMS

In order to anticipate drug-interactions of potential clinical significance the ability of the novel antidepressant, venlafaxine, to inhibit CYP2D6 dependent imipramine and desipramine 2-hydroxylation was investigated in human liver microsomes. The data obtained were compared with the selective serotonin re-uptake inhibitors, fluoxetine, sertraline, fluvoxamine and paroxetine. Venlafaxine's potential to inhibit several other major P450 s was also studied (CYP3A4, CYP2D6, CYP1A2).

METHODS

Ki values for venlafaxine, paroxetine, fluoxetine, fluvoxamine and sertraline as inhibitors of imipramine and desipramine 2-hydroxylation were determined from Dixon plots of control and inhibited rate data in human hepatic microsomal incubations. The inhibitory effect of imipramine and desipramine on liver microsomal CYP2D6 dependent venlafaxine O-demethylation was determined similarly. Venlafaxine's IC50 values for CYP3A4, CYP1A2 CYP2C9 were determined based on inhibition of probe substrate activities (testosterone 6 beta-hydroxylation, ethoxyresorufin O-dealkylase and tolbutamide 4-hydroxylation, respectively).

RESULTS

Fluoxetine, paroxetine, and fluvoxamine were potent inhibitors of imipramine 2-hydroxylase activity (Ki values of 1.6 +/- 0.8, 3.2 +/- 0.8 and 8.0 +/- 4.3 microM, respectively; mean +/- s.d., n = 3), while sertraline was less inhibitory (Ki of 24.7 +/- 8.9 microM). Fluoxetine also markedly inhibited desipramine 2-hydroxylation with a Ki of 1.3 +/- 0.5 microM. Venlafaxine was less potent an inhibitor of imipramine 2-hydroxylation (Ki of 41.0 +/- 9.5 microM) than the SSRIs that were studied. Imipramine and desipramine gave marked inhibition of CYP2D6 dependent venlafaxine O-demethylase activity (Ki values of 3.9 +/- 1.7 and 1.7 +/- 0.9 microM, respectively). Venlafaxine did not inhibit ethoxyresorufin O-dealkylase (CYP1A2), tolbutamide 4-hydroxylase (CYP2C9) or testosterone 6 beta-hydroxylase (CYP3A4) activities at concentrations of up to 1 mM.

CONCLUSIONS

It is concluded that venlafaxine has a low potential to inhibit the metabolism of substrates for CYP2D6 such as imipramine and desipramine compared with several of the most widely used SSRIs, as well as the metabolism of substrates for several of the other major human hepatic P450s.

Contribution of lysosomal trapping to the total tissue uptake of psychotropic drugs

The present study was aimed at assessing individual contributions of the phospholipid binding and lysosomal trapping to the total tissue uptake of psychotropic drugs with different chemical structures, such as promazine, imipramine, amitriptyline, fluoxetine, sertraline (basic lipophilic drugs) and carbamazepine (lipophilic, but not basic). We also tried to find out whether lysosomal trapping may be involved in the pharmacokinetic interactions in clinical combinations of psychotropics. Uptake experiments were carried out on slices of various rat tissues as a system with intact lysosomes. Initial concentration of each drug was 5 microM. The results were compared with those obtained in the presence of the "lysosomal inhibitors", ammonium chloride or monensin. The basic lipophilic psychotropics showed high uptake in tissues known for the abundance of lysosomes, mainly the lungs. The highest drug accumulation was found for promazine and amitriptyline. "Lysosomal inhibitors" significantly decreased the uptake of the basic lipophilic drugs, particularly in the lungs and liver. The most potent effect was observed for amitriptyline, imipramine and promazine. The brain showed moderate accumulation of basic lipophilic psychotropics and the effect of the "lysosomal inhibitors" was significant only in the case of amitriptyline, imipramine and sertraline. The only exception to the above regularity were imipramine and sertraline which were taken up more extensively by the adipose tissue than by lysosome-rich tissues such as the lungs or liver. Carbamazepine did not show lysosomotropism. Amitriptyline and promazine mutually decreased their uptake by lung slices when the drugs were incubated jointly. In the presence of ammonium chloride the interaction did not occur. In conclusion, the obtained results show that (1) the lysosomal trapping is an important factor determining the distribution of the basic lipophilic psychotropics; however (2) their tissue uptake depends more on the phospholipid binding than on the lysosomal trapping; (3) the lysosomal trapping may be involved in the pharmacokinetic interactions between psychotropics.

Pharmacokinetics of sertraline and its N-demethyl metabolite in elderly and young male and female volunteers

A nonblinded study was conducted to compare the pharmacokinetic properties of the selective serotonin reuptake inhibitor sertraline in 22 young (aged 18 to 45 years) and 22 elderly (> 65 years) volunteers, of whom half were male and half were female. In this study, sertraline was administered at a dosage of 200mg once daily (the maximum recommended daily dosage) for 21 days after upward dosage titration from 50 mg/day over a 9-day period. Thus, this study was designed to measure the effect of age and gender on the pharmacokinetic properties of sertraline at the maximum dosage recommended for clinical use. The terminal elimination half-life (t1/2 beta ) of sertraline was similar in young females, elderly males and elderly females (mean t1/2 beta ranged from 32.1 to 36.7 hours in these groups) but shorter (22.4 hours) in the young males. The mean maximum plasma sertraline concentration (Cmax) and the mean steady-state area under the plasma concentration-time curve from time zero to 24 hours postdose (AUC24) were also similar between the young females, elderly males and elderly females, but were approximately 25% lower in the young males. The time to Cmax was unaffected by age or gender and ranged from 6.4 to 6.9 hours. N-Demethylsertraline is the principal metabolite of sertraline and does not contribute significantly to its serotonergic actions. The mean values for N-demethylsertraline trough plasma concentrations, AUC24 and Cmax were comparable in elderly males and females and young females but lower in young males. The ratios of mean AUC24 and Cmax for N-demethylsertraline to the AUC24 and Cmax for sertraline were similar between the 4 groups.

Sertraline. Chronopharmacokinetics and the effect of coadministration with food

Two nonblinded single-dose randomised 3-way crossover studies were conducted in healthy male volunteers to determine the effect of the time of administration (morning vs evening) and the effect of food on the pharmacokinetics of sertraline tablets. There were no significant treatment effects on the mean area under the plasma concentration-time curve (AUC), mean peak plasma sertraline concentration (Cmax), mean time to reach Cmax (tmax), mean terminal elimination half-life, or the mean elimination rate constant in either study. The results of these 2 studies show that the bioavailability and elimination of sertraline tablets are not influenced by the time of administration or administration with or without food. Thus, sertraline tablets offer the flexibility of morning or evening administration, to patients in the fasting or nonfasting state.

Platelet serotonin transporter in children and adolescents with obsessive-compulsive disorder or Tourette's syndrome

Previous studies of serotonin transporter protein (5HTPR) indexed in platelets by 3H-imipramine demonstrate reduction in children with comorbid obsessive-compulsive disorder (OCD) and Tourette's syndrome (TS).

OBJECTIVE

To use the 5HTPR selective ligand 3H-paroxetine and homogeneous diagnostic groups to reevaluate these findings.

METHOD

Platelet Kinetic binding parameters were evaluated using standard techniques from medication-free child and adolescent patients with OCD (n = 18), with TS (n = 10), and normal controls (n = 19).

RESULTS

Baseline binding capacity (Bmax) was significantly reduced in patients with OCD (1,342 +/- 952 fmol/mg; protein p < .01) compared with normal controls (2,486 +/- 1309 fmol/mg) and TS patients (2,420 +/- 1,069 fmol/mg; p < .05). Among OCD patients who were subsequently treated on an open-label basis with selective serotonin reuptake inhibitor (SSRI), Bmax values at baseline differentiated between responders (1,718 +/- 1,041 fmol/mg) and nonresponders (802 +/- 713 fmol/mg protein; p < .05). Response to SSRI was greatest in patients with a positive family history of OCD. Among responders (n = 10), baseline Yale-Brown Obsessive Compulsive Scale and Bmax were positively correlated (r = .76, p = .01), as was Clinical Global Impression (r = .67, p = .03).

CONCLUSIONS

Platelet 5HTPR capacity (Bmax) is reduced in children and adolescents with OCD, but not in those with TS. 5HTPR may be an indirect measure of basal serotonergic tone.

The disposition of fluoxetine but not sertraline is altered in poor metabolizers of debrisoquin

BACKGROUND

Substrates and inhibitors of the cytochrome P450 isozyme CYP2D6 have overlapping structural characteristics. Two prototype serotonin uptake inhibitors, sertraline and fluoxetine, share these structural criteria and have been identified as potent inhibitors of CYP2D6 in vitro. The current study was undertaken to investigate whether genetically determined CYP2D6 activity alters the disposition of sertraline or fluoxetine or both.

METHODS

Single doses of sertraline (50 mg) and fluoxetine (20 mg) were administered successively to 20 young men with high (extensive metabolizers; n = 10) and low (poor metabolizers; n = 10) CYP2D6 activity. Blood and urine samples were collected for 5 to 7 half-lives and sertraline, desmethylsertraline, fluoxetine, and norfluoxetine were determined by GC and HPLC techniques.

RESULTS

Poor metabolizers had significantly greater fluoxetine peak plasma concentrations (Cmax; increases 57%), area under the concentration versus time curve (AUCzero-->infinity; increases 290%), and terminal elimination half-life (increases 216%) compared with extensive metabolizers. The total amount of fluoxetine excreted in the urine during 8 days was almost three times higher in poor metabolizers than in extensive metabolizers (719 versus 225 micrograms; p < 0.05), whereas the total amount of norfluoxetine excreted in urine of poor metabolizers was about half of that of extensive metabolizers (524 versus 1047 micrograms; p < 0.05). Norfluoxetine Cmax and AUCzero-->t were significantly smaller in poor metabolizers (decreases 55% and decreases 53%, respectively), and the partial metabolic clearance of fluoxetine into norfluoxetine was 10 times smaller in this group (4.3 +/- 1.9 versus 0.4 +/- 0.1 L/hr; p < 0.05). No significant differences between extensive and poor metabolizers were found for sertraline and desmethylsertraline pharmacokinetics.

CONCLUSION

These data indicate that poor metabolizers accumulate fluoxetine but not sertraline and that CYP2D6 plays an important role in the demethylation of fluoxetine but not of sertraline.

HPLC of sertraline and norsertraline in plasma or serum

A simple method for the measurement of sertraline and norsertraline in plasma or serum suitable for use in single-dose pharmacokinetic studies has been developed. Internal standard solution, aqueous fenethazine (10 mg/L) (20 microL), and Tris buffer (2 mol/L), pH 10.6) (100 microL) were added to plasma (200 microL). Sertraline, norsertraline and the internal standard were extracted into methyl tert-butyl ether (200 microL) by mixing (30 s) and centrifugation (11,000 r.p.m., 4 min). A portion (100 microL) of the extract was injected onto a Spherisorb S5SCX HPLC column (150 x 4.6 mm i.d.) which was eluted with methanol:water (19 + 1) containing ammonium perchlorate (40 mmol/L), final pH 7.0. Detection was by UV monitoring (215 nm). The concentration of each analyte in each sample was calculated from the calibration graph (peak-height ratio of analyte to that of the internal standard against concentration) obtained after analysis of plasma samples containing known amounts of sertraline and norsertraline. The limit of accurate measurement of the assay was 10 micrograms/L) sertraline and 20 micrograms/L) norsertraline.

Depression: making the diagnosis and using SSRIs in the older patient

Depression often goes unrecognized and untreated in older adults, in part because of its atypical presentation and the comorbid medical conditions in this population. Depression may coexist with dementia and is more often seen in patients with certain medical illnesses. Drug therapy is effective in treating depression in 65 to 75% of older patients. Selective serotonin reuptake inhibitors (SSRIs) are often used in this population because of their proven efficacy, safety, and tolerability. The most common side effects of SSRIs are GI disturbances and headaches, which may be minimized by slow dose escalation. Compared with younger adults, the elderly generally require smaller doses but show a similar time course of response to anti-depressant therapy.

Influence of liver cirrhosis on sertraline pharmacokinetics

Sertraline is a serotonin reuptake inhibitor. The enhancement of serotoninergic transmission is associated with antidepressant activity. In order to determine the pharmacokinetics of sertraline in patients with chronic stable hepatic insufficiency, 10 patients were matched (age, weight, sex) with 10 healthy subjects in an open study. Each participant received a single capsule containing the equivalent of 100 mg sertraline base. Blood samples were taken during 264 h after administration for measurement of plasma concentrations of sertraline. The results confirm that the oral clearance of sertraline is reduced with a 1.7-fold increase in Cmax and a significant prolongation in elimination half-life in hepatically impaired patients.

Absence of effect of sertraline on time-based sensitization of cognitive impairment with haloperidol

This double-blind, randomized, placebo-controlled study evaluated the effects of haloperidol alone and haloperidol plus sertraline on cognitive and psychomotor function in 24 healthy male subjects.

METHOD

All subjects received placebo on Day 1 and haloperidol 2 mg on Days 2 and 25. From Days 9 to 25, subjects were randomly assigned to either sertraline (12 subjects) or placebo (12 subjects); the sertraline dose was titrated from 50 to 200 mg/day from Days 9 to 16, and remained at 200 mg/day for the final 10 days of the drug administration period. Cognitive function testing was performed before dosing and over a 24-hour period after dosing on Days 1, 2, and 25.

RESULTS

Impairment of cognitive function was observed 6 to 8 hours after administration of haloperidol on Day 2 but was not evident 23 hours after dosing. When single-dose haloperidol was given again 25 days later, greater impairment with earlier onset was noted in several tests in both treatment groups, suggesting enhancement of this effect. There was no indication that sertraline exacerbated the impairment produced by haloperidol since an equivalent effect also occurred in the placebo group. Three subjects (2 on sertraline and 1 on placebo) withdrew from the study because of side effects. Ten subjects in each group reported side effects related to treatment. The side effect profiles of sertraline and of placebo were similar.

CONCLUSION

Haloperidol produced a clear profile of cognitive impairment that was not worsened by concomitant sertraline administration.

Hemodialyzability of sertraline

Sertraline is an antidepressant which selectively inhibits the neuronal uptake of serotonin in the central nervous system. The pharmacokinetics of sertraline in end-stage renal disease (ESRD) and the effect of hemodialysis on sertraline clearance is unknown. A dose of 100 mg sertraline was administered to two anuric hemodialysis patients after hemodialysis. During the next hemodialysis session, simultaneous pre- and post dialyzer blood samples were obtained at the start of and hourly throughout dialysis until completion. All spent dialysate was collected hourly, quantified and an aliquot retained. Additional blood samples were obtained approximately 20 hours after dialysis and prior to the next treatment. Serum and dialysate were assayed for sertraline by gas chromatography-mass spectroscopy. Initial sertraline serum concentrations were similar to those observed in subjects with normal renal function given the same sertraline dose, implying unaltered absorption and distribution. Sertraline was not detected in any dialysate sample. The elimination half-life was 42-92 h (normally 24-36 h), suggesting impaired clearance. Smaller doses of sertraline may be required in ESRD patients, yet post-hemodialysis supplementation is unnecessary.

Breastfeeding and sertraline: a 24-hour analysis

BACKGROUND

Few reports exist on the levels of antidepressants in breast milk or on observed behavioral effects, if any, of neonates who are breast-fed. Thus, a dilemma exists for women who would like to breast-feed but require psychotropic medications.

METHOD

Analysis of sertraline levels was performed on eight samples of breast milk obtained over a 24-hour period, after 3 weeks of breastfeeding, from a lactating patient taking sertraline and nortriptyline. During this same 24-hour period, two serum samples each were taken from mother and child for analysis of sertraline and nortriptyline levels. After 7 weeks of exclusive breastfeeding, an additional serum sample was obtained from mother and child for analysis of sertraline levels. Drug metabolites were not measured.

RESULTS

Breast milk levels of sertraline were lowest 1 hour before the ingestion of sertraline and highest 5 to 9 hours after ingestion of the drug. The infant's serum sertraline and nortriptyline levels were nondetectable.

CONCLUSION

These data indicate that sertraline levels in breast milk vary substantially over 24 hours and appear to be lowest within the 2 hours before and 1 hour after ingestion of the medication, with the peak probably occurring between Hours 1 and 9 postingestion. However, the absence of detectable serum sertraline and nortriptyline levels in the infant suggests that if either medication is present in infant serum, its concentration would be extremely low. No abnormal occurrences have been noted in the development of the infant. It would be important in future studies to measure metabolites in addition to medication levels since the former have been associated with untoward events in an infant.

Comparative pharmacokinetics of selective serotonin reuptake inhibitors: a look behind the mirror

The presently available selective serotonin reuptake inhibitors (SSRIs) citalopram, fluoxetine, fluvoxamine, paroxetine and sertraline, despite their common mechanism of action, differ in their chemical structure, metabolism and pharmacokinetics. From a clinical point of view, it is of relevance that potency to inhibit the cytochrome P450 isozyme CYP2D6 gradually decreases from paroxetine, fluoxetine, norfluoxetine, desmethylcitalopram, fluvoxamine, and sertraline down to citalopram, explaining to a great extent differences in pharmacokinetic interactions between the SSRIs and tricyclic antidepressants, which are metabolized by this enzyme. Fluvoxamine interacts with these drugs by a mechanism involving inhibition of CYP1A2, CYP3A4, and CYP2C19. Except for paroxetine, a substrate of CYP2D6, little is known about the enzymes implicated in the metabolism of SSRIs. Fluoxetine and citalopram are used as racemic drugs. Data on the stereoselectivity of their enantiomers in the inhibition of serotonin (5-HT) uptake in the animal brain, also those available on their metabolism and kinetics in humans, are presented. It may be concluded that for routine therapeutic drug monitoring, the plasma level measurement of the enantiomers of citalopram and fluoxetine is probably of little relevance. However, for the study of the structure-activity relationship between these drugs and the cerebral 5-HT transporter, the stereochemical differences of these enantiomers should be considered. In this sense, the enantiomers of these drugs could represent a promising tool to increase present knowledge.

Distribution of sertraline in postmortem cases

Sertraline is a potent inhibitor of serotonin reuptake in the central nervous system and is used clinically to treat depression and obsessive-compulsive behavior. Over the course of one year, there were seven cases investigated by the Office of the Chief Medical Examiner, State of Maryland, in which sertraline was identified in postmortem specimens. Heart blood concentrations in the seven cases ranged from 0.23 to 0.46 mg/L; desmethylsertraline concentrations ranged from 0.08 to 0.99 mg/L. One similarity with tricyclic antidepressants is the high liver concentrations of drug and metabolite relative to the blood. One unusual finding is the small concentrations of drug and metabolite in the urine relative to other specimens. In none of these cases was the cause of death related to sertraline intoxication.

Targeted pharmacotherapy in depression management: comparative pharmacokinetics of fluoxetine, paroxetine and sertraline

In contrast to tricyclic antidepressants (TCAs), the selective serotonin reuptake inhibitors (SSRIs) have a high affinity for the serotonin uptake site with little or no affinity for alpha-adrenergic, cholinergic or histaminic receptors. SSRIs, again in contrast to TCAs, do not slow intracardiac conduction. These differences between TCAs and SSRIs are important in terms of both discomforting and more serious adverse effects. Despite their more focused effects, the SSRIs are as effective as TCAs in treating major depression. The SSRIs have similar properties in terms of their pharmacodynamics, but important differences in terms of pharmacokinetics and their effects on hepatic function. Sertraline, and the starting dose of paroxetine have an elimination half-life (t1/2) of approximately 24 h. However, the half-life of paroxetine, but not of sertraline, becomes longer at higher doses due to paroxetine's inhibition of its own clearance. At t1/2 of 24 h makes once-daily dosing feasible and allows for new steady-state concentrations and wash-out within a reasonable time after dose adjustment. Fluoxetine has a t1/2 of 2-4 days and has an active metabolite with a t1/2 of 7-15 days. Such a half-life makes dose titration more difficult, and can result in prolonged effects even after dose reduction or drug discontinuation. Sertraline has dose-proportional changes in plasma concentrations, in contrast to fluoxetine and paroxetine. Thus, dose increases with fluoxetine and paroxetine produce greater than expected changes in plasma drug concentration, and hence, in concentration-dependent effects.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of sertraline (Zoloft) and its major metabolite in postmortem specimens by gas and liquid chromatography

We report methods for the analysis of sertraline and desmethylsertraline in postmortem biological fluids. The extraction method is based on a widely used procedure employing n-butyl chloride, and instrumental analysis is performed using GC/MS and HPLC with photodiode array detection. We report retention index, mass spectral, and UV-vis properties of the drug and its metabolite. Samples from three sertraline-related deaths were analyzed and revealed concentrations up to 10 times greater than the normal therapeutic levels, although two of the deaths were obviously the result of other causes. We also noted in one case that the drug concentrations in central and peripheral blood were very similar, suggesting that postmortem distribution may be uniform.

Pharmacokinetics of desipramine coadministered with sertraline or fluoxetine

The pharmacokinetic interactions of sertraline and fluoxetine with the tricyclic antidepressant desipramine were studied in 18 healthy male volunteers phenotyped as extensive metabolizers of dextromethorphan. Concentrations in plasma were determined after 7 days of desipramine (50 mg/day) dosing alone, during the 21 days of desipramine and selective serotonin reuptake inhibitor (SSRI) coadministration (fluoxetine, 20 mg/day; sertraline, 50 mg/day), and for 21 days of continued desipramine administration after SSRI discontinuation. Desipramine Cmax was increased 4.0-fold versus 31% and AUC0-24 was increased 4.8-fold versus 23% for fluoxetine versus sertraline, respectively, relative to baseline after 3 weeks of coadministration. Desipramine trough concentrations approached baseline within 1 week of sertraline discontinuation but remained elevated for the 3-week follow-up period after fluoxetine discontinuation. Concentrations of SSRIs and their metabolites correlated significantly with desipramine concentration changes (for fluoxetine/norfluoxetine, r = 0.94 to 0.96; p < 0.001; for sertraline/desmethylsertraline, r = 0.63; p < 0.01). Thus, sertraline had less pharmacokinetic interaction with desipramine than did fluoxetine at their respective, minimum, usually effective doses.

Progress report on the anorectic effects of dexfenfluramine, fluoxetine and sertraline

This progress report on the anorectic effect of serotoninergic indirect antagonists compares the action of D-fenfluramine, fluoxetine and sertraline and their N-dealkylated metabolites. Brain levels of drugs and their metabolites were measured after equi-active anorectic doses. Fluoxetine and sertraline inhibit 5-HT uptake in vitro with a potency which is at least one order of magnitude higher than for D-fenfluramine while all three drugs release 5-HT from synaptosomes and the active concentrations are closer to the brain concentrations reached after anorectic doses. However, a number of differences have been observed between D-fenfluramine and fluoxetine regarding the mechanisms of 5-HT release. Furthermore fluoxetine affected storage of 5-HT in vesicles much more than D-fenfluramine did. The anorectic effect induced by fluoxetine was not antagonized by antiserotoninergic drugs. No evidence of an involvement of CCK in the anorectic effect of D-fenfluramine was found when food intake was determined in rats previously submitted to food deprivation.

Sertraline. A review of its pharmacodynamic and pharmacokinetic properties, and therapeutic potential in depression and obsessive-compulsive disorder

Sertraline is a selective inhibitor of central serotonin reuptake. Thus, it enhances serotoninergic transmission--a property which appears to explain its antidepressant activity. Its elimination half-life (approximately 26 hours) makes it suitable for once daily administration. Although clinical experience with sertraline is limited, it appears to possess antidepressant efficacy similar to that of amitriptyline and dothiepin, marginally better than imipramine, and significantly better than placebo. Additionally, sertraline is the only antidepressant licensed in the UK for the prevention of recurrence of depression, and preliminary findings suggest that the drug may also be effective in the treatment of obsessive-compulsive disorder. Sertraline and other serotonin reuptake inhibitors possess tolerability advantages over tricyclic antidepressants. Sertraline has minimal anticholinergic activity, is essentially devoid of cardiovascular effects, has a wide therapeutic index and may be administered to elderly patients or those with underlying cardiovascular disorders. However, as with other serotonin reuptake inhibitors, sertraline has been associated with gastrointestinal disturbances (nausea, diarrhoea/loose stools) and male sexual dysfunction (primarily ejaculatory disturbance), although each of these effects is usually mild and transient, decreasing in frequency with continued treatment. As a drug class, serotonin reuptake inhibitors such as sertraline appear to provide significant advantages compared with the more established antidepressant agents, particularly in terms of tolerability. Although much broader clinical experience is required before sertraline's full therapeutic potential can be realised, if future studies confirm the encouraging initial findings, sertraline will undoubtedly become an important option in the treatment of depression.

The pharmacologic profile of paroxetine, a new selective serotonin reuptake inhibitor

Paroxetine is a highly potent and selective inhibitor of serotonin reuptake, being more potent in vitro than fluoxetine, fluvoxamine, and sertraline. In contrast to the tricyclic antidepressants, paroxetine has little affinity for catecholaminergic or histaminergic systems. Paroxetine is well absorbed from the gastrointestinal tract and undergoes first-pass metabolism that is partially saturable. Unlike the metabolites of fluoxetine and sertraline, the metabolites of paroxetine are pharmacologically inactive in vivo. Steady-state paroxetine plasma concentrations are generally achieved within 4 to 14 days of commencing therapy and remain stable thereafter. The pharmacokinetics of paroxetine are also consistent with once-daily dosing. This pharmacologic and pharmacokinetic profile, taken together with extensive clinical data, indicates that paroxetine is a valuable addition to the physician's armamentarium for the treatment of depression.

Pharmacokinetics of the selective serotonin reuptake inhibitors

The pharmacokinetic properties of the newer specific serotonin (5-HT) reuptake inhibitors are reviewed. Fluoxetine, paroxetine, sertraline, and fluvoxamine show kinetic characteristics similar to those of the older tricyclic antidepressants. They are well absorbed orally but exhibit an extensive first-pass extraction in the liver. They are widely distributed in body tissues and highly bound to plasma proteins. The clearance of these drugs by the body is accomplished almost entirely by hepatic metabolism. Fluoxetine and sertraline both produce a pharmacologically active metabolite, although insufficient data are available to evaluate the clinical significance of desmethylsertraline. With the exception of fluoxetine, which has an elimination half-life of 2 to 3 days, the other drugs have half-lives of about 1 day. Available data indicate that paroxetine and fluvoxamine achieve steady state within 4 to 14 days of chronic dosing, whereas for fluoxetine, and particularly norfluoxetine, steady state is not reached for weeks. The pharmacokinetics of these drugs are characterized by marked intersubject variability. Only preliminary data are available on steady-state plasma concentrations achieved during treatment and correlations to therapeutic or adverse effects.

Clinical implications of the pharmacology of sertraline

Sertraline is slowly absorbed after oral administration, with peak plasma concentrations at 6-8 h. Plasma concentrations are linearly related to dose. The elimination half-life is about 32 h; metabolism is by demethylation to an inactive metabolite. Once-daily dosing is recommended, with steady state being reached after about 7 days. The kinetics of sertraline in the elderly and in patients with renal impairment are similar to those in young healthy female volunteers. In young male volunteers, peak plasma concentrations were lower, and elimination half-life shorter, than in elderly men or both groups of women. Nevertheless, no reduction in dosage is recommended for these groups. Sertraline is highly active in animal models of depression, and administration of the drug to healthy human beings causes a selective, dose-related inhibition of 5-hydroxytryptamine (5-HT) uptake into blood platelets. Single doses of sertraline in volunteers caused changes in the quantitative pharmaco-electroencephalogram suggesting antidepressant and anxiolytic actions, with sedative potential evident only at doses of 200 mg or more. Sertraline does not impair psychomotor performance, including simulated car driving, and overall seems neither stimulating nor sedating: an increase in critical flicker fusion threshold suggests a slight alerting effect, whereas subjective tests indicate an increase in perceived sedation at doses of 100 mg or more. No potentiation of the effects of ethanol has been noted in either young or elderly subjects. No adverse effects on the electrocardiogram, blood pressure, or systolic time intervals have been detected, and sertraline lacks anticholinergic action. These studies imply a low probability of adverse central nervous and cardiovascular effects. Sertraline is probably a weak inducer of hepatic microsomal enzyme activity. Sertraline does not affect the clearance of lithium but there may be a pharmacodynamic interaction which leads to increased tremor when the drugs are given together. No clinically relevant effects were noted in the interaction studies with digoxin, atenolol and diazepam. The pharmacokinetics and pharmacodynamics of sertraline are generally favourable. However, caution is needed when sertraline is given to patients receiving lithium or drugs with a low therapeutic ratio, such as corticosteroids, oral hypoglycaemic agents, and warfarin.

Sertraline: a new specific serotonin reuptake blocker

Sertraline hydrochloride is a new naphthylamino compound that specifically blocks neuronal reuptake of serotonin. It is currently available in the United Kingdom and under review in the US. Sertraline follows first-order kinetics, with a plasma elimination half-life of 24-26 hours. It is highly bound to plasma proteins and has a large volume of distribution. Multicenter studies conducted by the manufacturer have shown sertraline to be efficacious in the treatment of depression and obsessive-compulsive disorder. The daily dose will range from 50 to 200 mg/d for the treatment of depression. The adverse-effect profile differs greatly from the tricyclic antidepressants, but is similar to that of fluoxetine. The most prominent adverse effects are gastrointestinal (nausea, diarrhea/loose stools, dyspepsia).

Transformation of arylamines into direct-acting mutagens by reaction with nitrite

Arylamines including aniline (I), 1-naphthylamine (II), 2-naphthylamine (III), 2-aminofluorene (IV), 1-aminoanthracene (V) and 1-aminopyrene (VI) were treated with 4 equivalent amounts of nitrite at pH3 and 37 degrees C for 4 h. The reaction mixtures of I, IV, V and VI showed mutagenicity to Salmonella typhimurium TA98 and TA100 strains without metabolic activation. The numbers of His+ revertant colonies to TA98 strain were 110/0.05 mumole I, 970/0.055 mumole IV, 620/0.10 mumole V and 870/0.02 mumole VI. These arylamines were converted into mutagens with diazoquinone, diazonium and nitro functions depending on their structures. The mutagen from I was p-diazoquinone (I2). The mutagen from IV was highly unstable fluorene-2-diazonium salt (IV1). The mutagens from V were N3O3-introduced anthracene (V1-1) and 1-nitroanthracene (V2), and those from VI were unidentified nitro-introduced compound (VI1) and 1-nitropyrene (VI2).

Sertraline and cocaine-induced locomotion in mice. I. Acute studies

The present study assessed the behavioral and pharmacokinetic interaction between the serotonin uptake blocker sertraline and cocaine in C57BL/6ByJ mice. Pretreatment with sertraline (1-32 mg/kg IP) did not affect the total amount of spontaneous locomotor activity during 50 min following administration of cocaine (15-40 mg/kg IP). At doses of sertraline (16 and 32 mg/kg) much higher than those found to inhibit ex vivo neuronal uptake of serotonin by 50% (1-2 mg/kg), the peak of cocaine-induced locomotor activity was shifted towards a later time. A similar effect was seen after pretreatment with serotonin uptake blockers other than sertraline, and also after desipramine. Sertraline (16 and 32 mg/kg), given 60 min prior to cocaine, did not affect levels of cocaine in brain and plasma, and cocaine administration did not alter the brain level of sertraline. Although female mice were more responsive to cocaine than male mice, they were not different in their response to sertraline.