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At least 109 records · Page 6Linked to original sources
PubMed2003

Blockade of HERG potassium currents by fluvoxamine: incomplete attenuation by S6 mutations at F656 or Y652.

1. Pharmacological blockade of the Human ether-a-go-go related gene (HERG) potassium channel is commonly linked with acquired long QT syndrome and associated proarrhythmia. The objectives of this study were (i) to identify and characterise any inhibitory action on HERG of the selective-serotonin re-uptake inhibitor fluvoxamine, (ii) to then determine whether fluvoxamine shared the consensus molecular determinants of HERG blockade of those drugs so far tested. 2. Heterologous HERG potassium current (I(HERG)) was measured at 37 degrees C, using the whole-cell patch-clamp technique, from a mammalian cell line (Human embryonic kidney 293) expressing HERG channels. I(HERG) tails, following repolarisation from +20 to -40 mV, were blocked by fluvoxamine with an IC(50) of 3.8 micro M. 3. Blockade of wild-type HERG was of extremely rapid onset (within 10 ms) and showed voltage dependence, with fluvoxamine also inducing a leftward shift in voltage-dependent activation of I(HERG). Characteristics of block were consistent with a component of closed channel (or extremely rapidly developing open channel) blockade and dependence on open and inactivated channel states. The attenuated-inactivation mutation S631A partially reduced the blocking effect of fluvoxamine. 4. The S6 mutations, Y652A and F656A, and the pore helix mutant S631A only partially attenuated blockade by fluvoxamine at concentrations causing profound blockade of wild-type HERG. 5. All HERG-blocking pharmaceuticals studied to date have been shown to block F656 mutant channels with over 100-fold reduced potency compared to their blockade of the wild-type channel. Fluvoxamine is therefore quite distinct in this regard from previously studied agents.

Amino Acid Substitution↗
PubMed2006

Phencyclidine-induced cognitive deficits in mice are improved by subsequent subchronic administration of fluvoxamine: role of sigma-1 receptors.

This study was undertaken to examine the effects of the selective serotonin reuptake inhibitors fluvoxamine and paroxetine on cognitive deficits in mice after repeated administration of the N-methyl-D-aspartate receptor antagonist phencyclidine (PCP). In the novel object recognition test, repeated administration of PCP (10 mg/kg/day, 10 days) significantly decreased the exploratory preference in the retention test session, but not in the training test session. PCP-induced cognitive deficits were significantly improved by subsequent subchronic (2-week) administration of fluvoxamine (20 mg/kg/day), but not paroxetine (10 mg/kg/day). Furthermore, the effect of fluvoxamine on PCP-induced cognitive deficits was antagonized by co-administration of the selective sigma-1 receptor antagonist NE-100 (1 mg/kg/day). Moreover, PCP-induced cognitive deficits were also significantly improved by subsequent subchronic (2-week) administration of the selective sigma-1 receptor agonist SA4503 (1 mg/kg/day) or neurosteroid dehydroepiandrosterone 3-sulfate (DHEA-S; 25 mg/kg/day). The effects of SA4503 or DHEA-S were also antagonized by co-administration of NE-100 (1 mg/kg/day), suggesting the role of sigma-1 receptors in the active mechanisms of these drugs. In contrast, acute single administration of these drugs (fluvoxamine, paroxetine, SA4503) alone or combination with NE-100 did not alter PCP-induced cognitive deficits. The present study suggests that agonistic activity of fluvoxamine at sigma-1 receptors plays a role in the active mechanisms of fluvoxamine on PCP-induced cognitive deficits in mice. Therefore, sigma-1 receptor agonists such as fluvoxamine would be potential therapeutic drugs for the treatment of the cognitive deficits of schizophrenia.

Analysis of Variance↗
PubMed1999

Addition of low-dose fluvoxamine to low-dose clozapine monotherapy in schizophrenia: drug monitoring and tolerability data from a prospective clinical trial.

Combining fluvoxamine and clozapine may be a strategy to improve therapeutic effects on negative symptoms in schizophrenic patients. Fluvoxamine, however, markedly inhibits the metabolism of clozapine, and hazardous side effects may result. This study prospectively investigated the safety and tolerability of an add-on therapy with fluvoxamine to a clozapine monotherapy in schizophrenic patients. Sixteen schizophrenic patients received 50 mg fluvoxamine as a comedication after having reached steady-state conditions under clozapine monotherapy. Patients were monitored for subjective adverse events, laboratory parameters, EEG and ECG recordings, orthostatic hypotension and their psychopathology. Concomitantly, serum concentrations of clozapine and metabolites were measured during monotherapy and after addition of fluvoxamine. In all patients, the serum concentrations of clozapine and metabolites were markedly increased (average: 2-3 fold, up to 5 fold for clozapine) after addition of fluvoxamine. Side effects remained almost unchanged in frequency and severity in spite of the pharmacokinetic interactions. ECG or laboratory parameters and orthostatic tests were similar under monotherapy and comedication. Minimal increases of EEG abnormalities were observed, but they were not associated with clinical impairment. Epileptic activities were always absent. The psychopathology improved which continued after start of the comedication. Though the addition of fluvoxamine to clozapine medication was well tolerated and critical side effects were absent, the combined treatment should be controlled by drug monitoring, as serum concentrations of clozapine increased to unpredictably high levels. Further studies have to find out if the combined treatment could be advantageous to clozapine monotherapy.

Adolescent↗
PubMed1998

Serum concentrations of fluvoxamine and clinical effects. A prospective open clinical trial.

This pilot study examined prospectively blood serum concentrations of fluvoxamine, side effects and therapeutic response after a fixed dosage of 100 mg fluvoxamine/day for 14 days. Twenty male and female patients who met the DSM-IV criteria of a major depression received 50 mg fluvoxamine b.i.d. for two weeks. On days 7 and 14 side effects and therapeutic response were registered and serum concentrations of fluvoxamine were determined. A Receiver Operating Characteristic (ROC) curve was constructed to determine a possible relationship between serum concentrations and clinical effects. The serum concentrations of fluvoxamine were highly variable, even when dosages were corrected for body weight, ranging between 23 to 227 microg/l. No relationship between serum concentrations and side effects was detectable. On the other hand, ROC analysis, conducted on day 14, revealed a significant upper concentration threshold of 85 microg/l (p < 0.01) with no responder above this threshold. The results of this pilot study should be regarded as a hint at the possible therapeutic benefits of lower fluvoxamine serum concentrations by means of lower fluvoxamine dosages. Furthermore, this indicates for the first time that therapeutic drug monitoring might be useful for patients under antidepressant therapy with fluvoxamine.

Adult↗
PubMed1997

The effect of fluvoxamine on serum prolactin and serum sodium concentrations: relation to platelet 5-HT2A receptor status.

Hyperprolactinemia and hyponatremia are adverse drug reactions regularly reported for selective serotonin reuptake inhibitors. Results from animal studies suggest that serotonin receptors of different subtypes are involved in the mediation of these effects. We have investigated to what extent fluvoxamine alters serum prolactin and serum sodium levels and whether these effects are related to platelet 5-hydroxytryptamine 2A (5-HT2A) receptor status, as studied by [3H]lysergic acid diethylamide ([3H]LSD) binding. Eight healthy subjects were given fluvoxamine in increasing dosage from 25 mg/day to 200 mg/day during 4 weeks, and serum sodium and serum prolactin concentrations were obtained weekly. All subjects had normal prolactin and sodium levels before start of treatment. Two subjects had substantial increases in serum prolactin levels (up to 35 microg/L) during fluvoxamine treatment, and these two subjects had higher Bmax for platelet [3H]LSD binding before fluvoxamine treatment than the six other subjects (32.7 vs. 23.1 fmol/mg protein). There was a small, nonsignificant decrease (mean 1.0 mmol/L) in serum sodium levels after institution of fluvoxamine but a significant increase (mean 1.9 mmol/L) in serum sodium levels after discontinuation of the drug (p = 0.02). Bmax for [3H]LSD binding and change in serum sodium concentration after institution of fluvoxamine showed a significant positive correlation (r = 0.85;p = 0.007). The results indicate that fluvoxamine affects serum prolactin as well as serum sodium concentrations and lend indirect support to the suggestion that 5-HT2A receptors might be involved in the mediation of these effects.

Adult↗
PubMed2002

Fluvoxamine augmentation of olanzapine in chronic schizophrenia: pharmacokinetic interactions and clinical effects.

Olanzapine is a substrate of the cytochrome P450 enzyme (CYP) 1A2. In this study, pharmacokinetic interactions and clinical effects of adding the CYP1A2 inhibitor fluvoxamine to steady-state olanzapine was examined in patients suffering from schizophrenia. Eight patients had been treated for at least 3 months with 10 to 20 mg/day olanzapine. Fluvoxamine (100 mg/day) was added (week 0) to the olanzapine treatment and continued for 8 weeks. Concentrations of olanzapine and its metabolite N-desmethylolanzapine and of fluvoxamine were analyzed at weeks 0, 1, 4, and 8. Addition of fluvoxamine resulted in a 12% to 112% ( < 0.01) increase of olanzapine from 31 +/- SD 15 ng/mL (week 0) to 56 +/- 31 ng/mL (week 8) in all patients. N-desmethylolanzapine concentrations were not significantly changed ( > 0.05). Fluvoxamine concentrations were 48 +/- 26 ng/mL on week 1 and 83 +/- 47 ng/mL on week 8. It is concluded that fluvoxamine affects olanzapine degradation and thus increases olanzapine concentrations. Although the combination was well tolerated in this sample and the negative symptom response appeared to be favorable in at least five patients, the combination therapy of olanzapine and fluvoxamine should be used cautiously and should be controlled by therapeutic drug monitoring to avoid olanzapine-induced side effects or intoxications.

Adult↗
PubMed1989

A placebo-controlled inpatient comparison of fluvoxamine maleate and imipramine in major depression.

Fluvoxamine, a selective serotonin reuptake inhibitor, was investigated in a 6-week double-blind study among severely ill inpatients with DSM-III major depression. All but 1 patient also fulfilled criteria for melancholia. Following a 3-day placebo wash-out patients were randomly assigned to fluvoxamine, imipramine or placebo. Sixty of 81 patients completed at least 2 weeks following wash-out and were evaluated for efficacy. Analysis of covariance (controlling for baseline scores) showed significant (p less than 0.05) differences on CGI severity and BPRS total and a similar trend (p = 0.08) on the Hamilton Depression Scale. Fluvoxamine was superior (p less than or equal to 0.02) to both placebo and imipramine on these measures. Fluvoxamine's most common adverse effects were nausea and agitation. The number of fluvoxamine patients withdrawn for side-effects was less than imipramine and not significantly different than placebo. Fluvoxamine was not associated with significant changes in vital signs, ECG or laboratory tests. The results therefore indicate that fluvoxamine is a safe and highly effective treatment for hospitalized patients with major depression.

Adolescent↗
PubMed2000

Multicentre, double-blind, comparison of fluvoxamine and clomipramine in the treatment of obsessive-compulsive disorder.

The aim of this prospectively randomized, double-blind, parallel group, multicentre study was to compare the efficacy and tolerability of fluvoxamine and clomipramine in patients suffering from obsessive-compulsive disorder (OCD) (DSM-III-R). Fourteen centres participated in this trial. Sixty-eight patients were randomized to receive fluvoxamine and 65 to receive clomipramine. The duration of the study was 10 weeks. The two treatment groups showed a marked improvement of obsessive-compulsive symptomatology, as determined by the Yale-Brown Obsessive-Compulsive Scale, the National Institute of Mental Health Obsessive-Compulsive Global Scale and Clinical Global Impression. No statistically significant differences were found between fluvoxamine and clomipramine in terms of efficacy during the study. A similar number of patients in each group withdrew from the study prematurely, but there were more dropouts due to adverse events in the clomipramine group. Concerning tolerability, there were significantly more reports of constipation and dry mouth in the clomipramine group. The results show that fluvoxamine and clomipramine have similar efficacy in the treatment of patients suffering from OCD, but fluvoxamine is better tolerated. In view of the superior safety profile of fluvoxamine compared to clomipramine in terms of a risk-benefit assessment, the use of fluvoxamine would appear to be advantageous for this patient population.

Adult↗
PubMedDate not supplied

Topiramate versus fluvoxamine in the treatment of pathological gambling: a randomized, blind-rater comparison study.

Pathologic gambling (PG) is a highly prevalent and disabling impulse control disorder. Recent studies have demonstrated that PG patients respond well to treatment with SSRIs, mood stabilizers, and opioid antagonists. These findings support the idea that PG and other disorders of impulse control may be conceptualized as part of the obsessive-compulsive spectrum disorders. Pilot studies have shown topiramate to be effective in the treatment of specific disorders of impulse control. The aim of the study is to compare the effectiveness of topiramate versus fluvoxamine in the treatment of PG. Thirty-one male PGs were assigned in a randomized fashion to receive either topiramate (15/31) or fluvoxamine (16/31) pharmacotherapy for 12 weeks. A comprehensive psychiatric diagnostic evaluation was performed on all patients, and all patients were evaluated for symptoms of gambling, depression, and anxiety using the South Oaks Gambling Screen, the Hamilton Depression Rating Scale, the Hamilton Anxiety Rating Scale, the Yale-Brown Obsessive Compulsive Symptoms Scale, and the Clinical Global Impression-Improvement Scale. The rating scales were administered at baseline and at the 12-week endpoint. In addition, the patients completed self-report questionnaires about their demographic status. Twelve of the 15 patients from the topiramate group completed the 12-week treatment. Nine of the 12 topiramate completers reported full remission of gambling behavior, and 3 completers had a partial remission. The CGI-improvement score was significantly better for the topiramate group at the 12-week visit as compared with baseline (F = 10.5, P < 0.01, df = 2.31). In the fluvoxamine treatment group 8/16 patients completed the study, and 6/8 fluvoxamine completers reported a full remission, and the remaining 2/8 fluvoxamine completers reported a partial remission. The fluvoxamine group showed improvement in the CGI-improvement score at week 12, although this difference was not significant (F = 3.7, P < 0.08, df = 2.31). Topiramate and fluvoxamine monotherapy may be effective in the treatment of pathologic gambling.

Adolescent↗
PubMed1983

Neuroendocrine studies with fluvoxamine: animal data.

1 Administration of the potent 5-hydroxytryptamine (5-HT) re-uptake inhibitor fluvoxamine (25 mg/kg i.p. for 14 days) to adult cycling female rats did not alter either the number of oestrous episodes or the plasma concentrations of luteinizing hormone determined on days 2, 9 and 14 of treatment. 2 Fluvoxamine (25 mg/kg i.p.) induced in male rats a clear-cut lowering of beta-endorphin-like immunoreactivity from the anterior pituitary, but not the neurointermediate lobe, and increased concomitantly plasma levels of beta-endorphin and beta-lipotropin. 3 Fluvoxamine (12.5 and 25 mg/kg i.p.) stimulated, although not strikingly, prolactin (PRL) secretion in adult male rats, and at 25 mg/kg i.p. potentiated the PRL-releasing effect of 5-hydroxytryptophan (30 mg/kg i.p.). 4 In male rats treated daily with fluvoxamine (25 mg/kg i.p.) the PRL-releasing effect of an additional acute fluvoxamine administration (same dose) was abolished after 4 days maintenance treatment. One week after withdrawal of maintenance, which had been given for 14 days, the challenge dose of fluvoxamine was still unable to raise plasma PRL levels. 5 The endocrine effects of acute fluvoxamine administration are compatible with activation of 5-HT neurotransmission in the central nervous system. The mechanism(s) underlying tolerance to the PRL-releasing action of the drug is presently obscure. Its elucidation should provide insight into the mechanism of action of antidepressant drugs affecting 5-HT function.

5-Hydroxytryptophan↗
PubMed2005

Enantioselective disposition of lansoprazole in relation to CYP2C19 genotypes in the presence of fluvoxamine.

AIMS: Lansoprazole is affected by polymorphism of CYP2C19. The aim of this study was to examine the effects of fluvoxamine, a CYP2C19 inhibitor, on the pharmacokinetics of each lansoprazole enantiomer among three different CYP2C19 genotype groups. METHODS: Eighteen healthy subjects, of whom six each were homozygous extensive metabolizers (homEMs), heterozygous extensive metabolizers (hetEMs), or poor metabolizers (PMs) for CYP2C19, participated in the study. Each subject received either placebo or fluvoxamine, 25 mg twice daily for 6 days, then a single oral dose of 60 mg of racemic lansoprazole. The plasma concentrations of lansoprazole enantiomers and lansoprazole sulphone were subsequently measured for 24 h post lansoprazole administration using liquid chromatography. RESULTS: In the homEMs and hetEMs, fluvoxamine significantly increased the AUC(0, infinity) and C(max) and prolonged the elimination half-life of both (R)- and (S)-lansoprazole, whereas in the PMs, the only statistically significant effect of fluvoxamine was on the AUC(0, infinity) for (R)-lansoprazole. The mean fluvoxamine-mediated percent increase in the AUC(0, infinity) of (R)-lansoprazole in the homEMs compared with the PMs was significant (P = 0.0117); however, C(max) did not differ among the three CYP2C19 genotypes. On the other hand, fluvoxamine induced a significant percent increase in both the AUC(0, infinity) and C(max) for (S)-lansoprazole in the homEMs compared with the hetEMs (P = 0.0007 and P = 0.0125, respectively) as well as compared with the PMs (P < 0.0001 for each parameter). The mean R : S ratio for AUC(0, infinity) of lansoprazole in the homEMs was significantly different between the placebo and the fluvoxamine treatment groups (12.7 (9.1, 16.8) vs 6.4 (5.4, 7.4), respectively, P < 0.0001), though not in the PMs (5.5 (4.3, 6.7) vs 5.9 (5.3, 6.5), respectively). CONCLUSIONS: The magnitude of the contribution of CYP2C19 to the metabolism of (S)-lansoprazole is much greater compared with that of the (R)-enantiomer. In extensive metabolizers, hepatic CYP2C19 plays an important role in the absorption and elimination of lansoprazole, particularly the (S)-enantiomer.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed2003

Relationship between fluvoxamine and stress barometer for nocturnal enuresis.

BACKGROUND: It has been reported recently that fluvoxamine (a selective serotonin reuptake inhibitor) is effective and safe for children with monosymptomatic nocturnal enuresis (MNE). However, the exact mechanism by which fluvoxamine is beneficial in the treatment of MNE remains unknown. One possibility is that it controls emotional stress. METHODS: We divided children with MNE into primary MNE (n = 40) and secondary MNE (n = 7). We measured urinary 17-hydroxycorticosteroids (17-OHCS) and 17-ketosteroid sulfates (17-KS-S) as a stress barometer in children with MNE to evaluate adaptation to emotional stress before and during fluvoxamine treatment. We initially administered fluvoxamine at a dose of 25 mg at bedtime. If patients remained incontinent after 3 weeks, we increased the dose to 50 mg. RESULTS: Fluvoxamine was effective in 26 of 28 children (93%) with primary MNE and an abnormality of the stress barometer and in six of six children (100%) with secondary MNE and an abnormality of the stress barometer. Fluvoxamine was effective in only six of 12 children (50%) with primary MNE and normality of the stress barometer and was not effective in one child with secondary MNE and normality of the stress barometer. CONCLUSIONS: The stress barometer is useful clinically for evaluating the therapeutic effect of fluvoxamine for children with MNE.

17-Hydroxycorticosteroids↗
PubMed2002

Interaction between fluvoxamine and cotinine or caffeine.

We examined the relationships between plasma fluvoxamine concentrations and plasma levels of cotinine and caffeine, respectively, under steady-state conditions in 30 patients who met DSM-IV criteria for a major depressive disorder and who were being treated with fluvoxamine. The daily dosages of fluvoxamine ranged from 50 to 200 mg (mean +/- SD 108 +/- 42 mg). Eleven patients were smokers and the remaining 19 were nonsmokers. The plasma fluvoxamine concentrations were significantly higher in nonsmokers (0.92 +/- 0.40 ng/ml/mg) than in smokers (0.56 +/- 0.28 ng/ml/mg); in addition, a trend towards negative correlations was observed between the plasma fluvoxamine concentrations and the plasma cotinine levels, although it was not significant. Significant positive correlations were found between the plasma fluvoxamine concentrations and the plasma caffeine levels. These findings are compatible with those in earlier reports that cytochrome P450 1A2 plays a major role in fluvoxamine metabolism.

Adult↗
PubMed2003

Interaction study between fluvoxamine and quazepam.

It has been reported that fluvoxamine, an inhibitor of various cytochrome P450 enzymes, markedly inhibits the metabolism of several drugs. The purpose of the present study was to examine a possible interaction between fluvoxamine and quazepam. Twelve healthy male volunteers received fluvoxamine 50 mg/day or placebo for 14 days in a double-blind randomized crossover manner, and on the 4th day they received a single oral 20-mg dose of quazepam. Blood samplings and evaluation of psychomotor function by the Digit Symbol Substitution Test and Stanford Sleepiness Scale were conducted up to 240 hours after quazepam dosing. Plasma concentrations of quazepam and its active metabolites 2-oxoquazepam (OQ) and N-desalkyl-2-oxoquazepam (DOQ) were measured by high-performance liquid chromatography (HPLC). Fluvoxamine did not change plasma concentrations of quazepam but significantly decreased those of OQ from 6 to 12 hours and those of DOQ from 3 to 48 hours. The AUC ratio of OQ to quazepam was significantly lower in the fluvoxamine phase. Fluvoxamine did not affect psychomotor function at most of the time points. The present study suggests that fluvoxamine slightly inhibits the metabolism of quazepam to OQ, but this interaction appears to have minimal clinical significance.

Adult↗
PubMed2003

Changes in synaptic properties in cortical-limbic communications induced by repeated treatments with fluvoxamine in rats.

There is evidence indicating that dysregulation of coordinated interactions of the cortical-limbic circuitry is associated with anxiety and mood disorders. Our previous study has reported that an enhancement of long-term plasticity in the "limbic-cortical" pathway produced by repeated treatments with fluvoxamine may be involved in the clinical effects of a selective serotonin (5-HT) reuptake inhibitor (SSRI). Here we assessed the effects of single and repeated treatments with fluvoxamine on the synaptic transmission and plasticity in the "cortical-limbic" pathway in vivo. The evoked potentials in the basolateral amygdaloid complex (BLA) by stimulation of the medial prefrontal cortex (mPFC) in halothane-anesthetized rats were recorded. Single administration of fluvoxamine (10 and 30 mg/kg, i.p.) enhanced the efficacy of synaptic transmission at the mPFC-BLA synapses dose-dependently. The enhanced synaptic efficacy induced by 30 mg/kg fluvoxamine was suppressed after long-term administration of fluvoxamine (30 mg/kg per day x 21 days, orally). Repeated treatments with fluvoxamine affected short-term, but not long-term, synaptic plasticity in the mPFC-BLA pathway. These findings indicate that the 5-HTergic system contributes to modulation of synaptic changes in this pathway. Our results also suggest that different changes in synaptic properties in cortical-limbic communications induced by repeated treatments with fluvoxamine may be associated with therapeutic effects of SSRI.

Animals↗
PubMed2001

Fluvoxamine augmentation increases serum mirtazapine concentrations three- to fourfold.

OBJECTIVE: To report two cases of interaction between fluvoxamine and mirtazapine. CASE SUMMARY: A 17-year-old boy was treated with mirtazapine 30 mg/d. The addition of fluvoxamine 100 mg/d to the regimen caused a threefold increase in the mirtazapine concentration. This interaction was associated with increased anxiety. A second patient, a 43-year-old woman, was treated with mirtazapine 15 mg/d. There was a fourfold increase in her mirtazapine concentration and simultaneous mood improvements after augmentation with fluvoxamine 50 mg/d. DISCUSSION: This is the first report of any interaction between fluvoxamine and mirtazapine. Mirtazapine is mainly metabolized by cytochrome P450 isoenzymes CYP1A2, CYP2D6, and CYP3A4. Fluvoxamine and cimetidine Inhibit the same isoenzymes, but fluvoxamine is probably the only agent that causes a clinically significant interaction. CONCLUSIONS: Adding fluvoxamine to treatment with mirtazapine may cause a significant increase in mirtazapine concentration. This interaction may necessitate adjustment of the mirtazapine dosage.

Adolescent↗
PubMed2002

Fluvoxamine interaction with warfarin.

OBJECTIVE: To report a case of an elevated international normalized ratio (INR) in a patient receiving fluvoxamine and warfarin. CASE SUMMARY: A 79-year-old white woman was admitted for suicidal thoughts. Her medical history included depression, chronic obstructive pulmonary disorder, asthma, hypertension, atrial fibrillation with pacemaker placement, and breast cancer with lumpectomy and subsequent left mastectomy. Her medication list prior to admission was extensive, including warfarin 5 mg on Sunday, Monday, Wednesday, and Friday; warfarin 2.5 mg on Tuesday, Thursday, and Saturday, and citalopram 10 mg/d. Citalopram was changed to fluvoxamine during her hospital stay. This resulted in an elevated INR that persisted for approximately 7 days. DISCUSSION: The metabolism of warfarin involves several cytochrome P450 isoenzymes, including CYP1A2, CYP2C9, CYP2C19, and CYP3A4. Fluvoxamine has the potential to inhibit CYP1A2, CYP2C9, CYP2C19, and CYP3A4 to a significant degree. It also has 11 inactive metabolites that may contribute to enzyme inhibition. Fluvoxamine has an extensive elimination half-life of 17-22 hours after a single dose, which increases with multiple dosing by 30-50%. It can take approximately 10 days to reach a steady-state concentration. In the elderly, the half-life is increased by 50%. CONCLUSIONS: The coadministration of warfarin and fluvoxamine can result in an increase in the anticoagulant effect of warfarin. This anticoagulant effect can be seen for several days after the discontinuation of fluvoxamine. Our case emphasizes the need to closely monitor potential drug interactions in the elderly, especially those concerning fluvoxamine and warfarin.

Aged↗
PubMed1997

A double-blind comparison of fluvoxamine and paroxetine in the treatment of depressed outpatients.

BACKGROUND: Fluvoxamine and paroxetine, both serotonin selective reuptake inhibitors (SSRIs), were compared at two centers in a 7-week double-blind study in outpatients with major depression, diagnosed by DSM-III-R criteria. METHOD: Sixty patients were randomly assigned to receive dosage titrated upward to between 50-150 mg/day of fluvoxamine (N = 30) or 20-50 mg/day of paroxetine (N = 30). The mean +/- SD daily dose administered at the last assessment was 102 +/- 44 mg/day for fluvoxamine and 36 +/- 13 mg/day for paroxetine. Sixteen (53%) fluvoxamine-treated patients and 10 (33%) paroxetine-treated patients were titrated to the maximum permissible dosage of either drug. Sample size was calculated to provide at least 85% power at 5% level of significance to detect at least a 1.00-point difference in mean severity of adverse events, assuming a standard deviation of 1.0. RESULTS: Fluvoxamine and paroxetine were similarly effective in ameliorating depression as demonstrated by mean total scores of 10.9 +/- 7.3 (p < .00) and 11.5 +/- 7.4 (p < .00), respectively, in the Hamilton Rating Scale for Depression (HAM-D). Adverse events were mostly mild to moderate in severity. The most common events were headache (N = 17, 57%), nausea (N = 14, 47%), sweating (N = 10, 33%), somnolence (N = 9, 30%), diarrhea (N = 9, 30%), dry mouth (N = 8, 27%), dizziness (N = 8, 27%), and, among males, impotence (N = 3, 21%) and ejaculatory abnormality (N = 3, 21%) in the paroxetine group, and headache (N = 12, 40%), somnolence (N = 12, 40%), nausea (N = 11, 37%), dry mouth (N = 11, 37%), insomnia (N = 9, 30%), asthenia (N = 7, 23%), and dyspepsia (N = 7, 23%) in the fluvoxamine group. The only statistically significant difference between treatment groups was for sweating (33% paroxetine vs. 10% fluvoxamine, p = .028). CONCLUSION: Observed differences in some side effects, although not statistically significant, indicate that when a patient has difficulty tolerating one SSRI, the clinician may choose to change to a different agent within the same class.

Adolescent↗