Clinical development of citalopram

Transformation mechanisms of the antidepressant citalopram in a moving bed biofilm reactor: Substrate-depended pathways, eco-toxicities and enantiomeric profiles

Citalopram (CIT) is one of the most consumed antidepressants and frequently detected in aquatic environments worldwide. Conventional wastewater treatment cannot remove this neuronal active pharmaceutical efficiently. Past studies showed that moving bed biofilm reactors (MBBRs) can degrade CIT but the exact transformation pathways and toxicity reduction remained unclear. In this study, the effects of substrate stimulation on CIT transformation in an MBBR were systematically investigated. The results showed that a co-metabolic stimulation by acetate increased the transformation rate by 54 % and 24 % at high (300 μg/L) and environmental concentration (1.8 μg/L) of CIT, respectively. Conversely, the complex substrates in raw wastewater reduced the reaction rates by 44 %, suggesting a competitive inhibition on the enzymatic sites. The substrate stimulation changed the enantiomeric fraction (EF) of CIT from racemic (EF=0.5) to 0.60 at the high CIT concentrations, while those at lower concentrations resulted in an EF of 0.33, indicating that probably different enantioselective enzymes degraded CIT at high concentrations than at low concentrations, i.e., the presence of 300 µg/L CIT was possibly sufficient to induce the synthesis of different enantioselective enzymes, than those originally present. Through non-target and target analysis, in total 19 transformation products (TPs) including 7 TPs that were hitherto not mentioned in the literature were identified. Among these were quaternary amines, alkenes and conjugate TPs. The major transformation pathways were a) nitrile hydrolysis (up to 43 %), b) amide hydrolysis, and c) N-oxidation. Dosing acetate up-regulated significantly the amide hydrolysis, N-oxidation and conjugation pathways but inhibited the N-demethylation and α-carbon hydroxylation pathways. The in-silico toxicity assessment of CIT and its TPs suggested the overall eco-toxic potential of TPs was reduced by MBBR. Furthermore, the degradation under carbon-limited (famine) conditions favored the formation of the more toxic carboxamide, N-desmethyl and alkene TPs, while carbon-rich conditions, promoted the production of the less toxic carboxylic acid, N-oxide and ester TPs. Therefore, this study demonstrated that a) the co-metabolic stimulation of CIT metabolization by dosing a simple carbon source or b) inhibition of CIT metabolization by complex substrates; c) substrate stimulation made a difference on CIT transformation rates, enantiomeric profiles, pathways and toxic potentials. Overall, a simple-carbon co-metabolic stimulated MBBR was an efficient up-regulation strategy to minimize hazardous CIT and CIT-TPs as much as possible.

Unravelling Impaired Hypoalgesia at Rest and in Response to Exercise in Patients with Chronic Whiplash-Associated Disorders: Effects of a Single Administration of Selective Serotonin Reuptake Inhibitor versus Selective Norepinephrine Reuptake Inhibitor

(1) Background: Noradrenaline and serotonin have modulatory roles in pain signaling and in exercise-induced hypoalgesia. Patients with chronic whiplash-associated disorders often show impaired exercise-induced hypoalgesia. Therefore, this study aimed to examine the isolated effect of activating serotonergic or noradrenergic descending pathways on hypoalgesia at rest and in response to exercise in patients with chronic WAD by using respectively a single dose of a selective serotonin reuptake inhibitor (SSRI) and a selective norepinephrine reuptake inhibitor (NRI). (2) Methods: Twenty-five people with chronic WAD participated in this double-blind randomized controlled crossover experiment. Serotonin and noradrenaline concentrations were modulated by the oral ingestion of a single dose of citalopram (i.e., SSRI) or atomoxetine (i.e., SNRI). Quantitative sensory testing (including pressure pain thresholds and conditioned pain modulation) was measured before and after exercise in combination with no medication (1), atomoxetine (2), or citalopram (3) at three different test days. (3) Results: Random-intercept linear mixed models analysis was used to analyze pain outcomes (i.e., pain at rest and exercise-induced hypoalgesia) before and after exercise over the three conditions in patients with chronic WAD. No differences in pain at rest were found between the three conditions before exercise. The effect of exercise on pain outcome measures was not influenced by medication intake. The occupational status of the participants had a significant influence on the effect of exercise and medication on pain outcomes (p < 0.05). Patients working full-time had some positive effect of atomoxetine on pain facilitation (p < 0.05). Unemployed patients had some negative effect of citalopram on pain tolerance and experienced exercise-induced hypoalgesia (p < 0.05). (4) Conclusions: A single dose of citalopram or atomoxetine did not result in changes in hypoalgesia at rest and in response to exercise. These results do not support the use of SSRI or selective NRI to overcome impaired hypoalgesia at rest or in response to exercise in people with chronic WAD. Effect of exercise and medication on pain in patients with chronic WAD is influenced by the occupational status.

Analytical methodologies for the enantiodetermination of citalopram and its metabolites

Citalopram (CIT) is a highly selective serotonin reuptake inhibitor (SSRI) frequently used in the treatment of major depressive disorders. It has a chiral centre in its structure and is used in therapy both as a racemic mixture (R,S-CIT) and a pure enantiomer (S-CIT). The differences between the pharmacokinetic and pharmacological profiles of the two enantiomers are well established. Consequently, the development of new efficient chiral analysis methods for their enantiomeric separation is a topic of great actuality. CIT metabolism is stereoselective as it is metabolized in chiral active metabolites, which retain considerable SSRI activity and contribute to the pharmacological effect. Chiral analytical methods are employed for the determination of enantiomeric ratio in pharmaceutical preparations and for monitoring the enantiomer levels in biological samples for therapeutic and toxicologic purposes. The current study reviews the published literature for the chiral analysis of CIT and its metabolites based on chromatographic and electrophoretic methods coupled with UV, fluorescence and mass spectrometry detectors.

Psychopharmacologic interventions for repetitive behaviors in autism spectrum disorders

This article provides an overview of psychopharmacological treatments for repetitive behaviors in autism spectrum disorders (ASDs) in the context of current conceptualizations of this understudied core symptom domain. The available literature on the widely used selective serotonin reuptake inhibitors (SSRIs), including fluvoxamine, fluoxetine, citalopram, escitalopram, and sertraline, are reviewed. In addition to SSRIs, research on effects of other pharmacologic interventions such as divalproex sodium, risperidone, and the neuropeptide oxytocin are presented. To date, data are mixed for interventions commonly prescribed in clinical practice and suggest several areas of investigation in advancing research on the medication management of repetitive behaviors.

Anti-depressive Therapies After Heart Transplantation

OBJECTIVE

Despite an improved quality of life, about 33% of heart transplant recipients will develop depressive symptoms post-operatively. To date, no review has explored the efficacy and safety of pharmacologic or psychologic interventions in this patient group.

METHODS

We conducted a comprehensive Medline, EmBase, Psycinfo search for studies of the treatment of depression in heart transplant recipients.

RESULTS

We identified 34 studies of variable methodologic quality. Selective serotonin re-uptake inhibitors (SSRIs), particularly citalopram and new-generation anti-depressants (mirtazapine), seem to represent the best therapeutic choices for this population. Tricyclic anti-depressants (TCAs), and electroconvulsive therapy (ECT) should be reserved for severe depression unresponsive to other treatments, whereas monoamine oxidase inhibitors (MAOIs) should be avoided. St John's wort, an alternative herbal drug, has been associated with life-threatening immunosuppression. Psychologic therapy offers further advantages after heart transplantation.

CONCLUSIONS

Further well-conducted, randomized, controlled trials are needed to clarify the efficacy and the safety of pharmacologic (SSRIs and atypical anti-depressants) and psychologic interventions in the management of depression after heart transplantation.

Citalopram use in pregnancy: prospective comparative evaluation of pregnancy and fetal outcome

OBJECTIVE

Citalopram is a selective serotonin reuptake inhibitor indicated for depression. The safety of this medication in pregnancy has not been fully established. The purpose of this study was to investigate whether citalopram is associated with an increased incidence of adverse pregnancy outcomes.

STUDY DESIGN

Pregnant women who contacted the Motherisk Program, a Teratogen Information Center in Toronto, Ontario, with regard to the safety of citalopram in pregnancy were enrolled in the study. The exposed women were matched to a disease-matched group of women and a nonteratogenic group. All women were matched for age (+/- 2 years) and gestational age at time of first call to the Motherisk (+/- 2 weeks). A structured telephone follow-up interview was conducted following the expected date of confinement.

RESULTS

The total number of pregnant women enrolled in this study was 396 (132 women in each group). A total of 125 women took citalopram at least in the first trimester. Seventy-one (54%) women continued to take the drug throughout pregnancy. One hundred fourteen women (86%) had live births, 14 (11%) had spontaneous abortions, 2 (1.5%) had elective terminations, and 2 (1.5%) experienced stillbirths. Fetal survival rates, mean birth weights, and duration of pregnancy were not statistically different among the 3 groups. Of 108 live-born infants whose mothers were exposed to citalopram in the first trimester, there was 1 (0.9%) male infant born with a major malformation. There was a relative risk of 4.2 (95% confidence interval 1.71-10.26) in neonates exposed to citalopram close to term to be admitted to special-care nurseries as compared with the unexposed infants.

CONCLUSION

Citalopram use during the period of embryogenesis in pregnancy is not associated with an apparent major teratogenic risk. Late pregnancy use of citalopram is associated with increased risk of poor neonatal adaptation syndrome, recently described with other selective serotonin reuptake inhibitors.

Activity of citalopram on adenosine and serotonin circulating levels in depressed patients

Citalopram is a selective serotonin reuptake inhibitor used in the treatment of depression. Recent investigations have shown that it reduces in rat brain the release of excitatory amino neurotransmitters acid glutamate and aspartate by the involvement of the inhibitory neuromodulator adenosine. In this study, we described citalopram and serotonin levels in plasma and platelets, as well as plasma adenosine levels, in depressive patients during acute and chronic administration of citalopram. Twelve patients affected by Major Depression (DSM-IV) received a single oral dose of citalopram in the morning, 5 mg in the first 5 days, 10 mg from the 6th to the 10th day, and 20 mg from the 11th to the 40th day. Blood samples for citalopram, serotonin, and adenosine were collected at Time 0 and 4, 12 and 24 hours after drug administration on the first day of citalopram 5 mg, and on the first and the last day of citalopram 20 mg. Citalopram, serotonin, and adenosine concentrations in plasma increased after citalopram administration, and the highest levels were observed on the last day of treatment. Citalopram was detectable in platelets with concentrations showing a time variation similar to plasma values. Serotonin levels in platelets decreased after drug administration, reaching the lowest values on the last day of treatment.

An evaluation of efficacy and safety of reboxetine in elderly patients affected by “retarded” post-stroke depression

Depression occurs frequently in post-stroke patients and appears to be associated with an impairment in their rehabilitation and functional recovery. Although selective serotonin reuptake inhibitors (SSRI) are often used in post-stroke depression (PSD), it has been observed that only a subset of patients is responsive to this treatment. Other patients respond to tricyclic antidepressants or MAO inhibitors, which, however, may not have a favorable profile of safety and tolerability in post-stroke patients. In this double-blinded, placebo-controlled study, we evaluated the efficacy and tolerability of the noradrenaline reuptake inhibitor, reboxetine, in a subset of PSD patients classified as affected by "retarded" depression. Reboxetine (4 mg, twice daily, for 16 weeks) was administered to patients that developed depression after a single ischaemic or hemorrhagic stroke. We assessed the severity of depressive symptoms by the Beck Depression Inventory (BDI) and Hamilton Depression Rating Scale (HDRS). HDRS and BDI scores (mean+/-S.D.) at baseline were, respectively, 24+/-1.31 and 19.87+/-1.46 in the placebo group, 24.06+/-1.52 and 20.56+/-2.16 in the reboxetine group. After 16 weeks, HDRS and BDI mean scores were respectively 22.73+/-2.4 and 18.4+/-3.33 in the placebo group, 9.26+/-2.15 and 8.06+/-3.43 in the reboxetine group [p<0.01 versus the respective baseline (paired t-test); (#)p<0.01 versus retarded depressed patients treated with placebo (one-way analysis of variance (ANOVA) applied to the difference from baseline, associated with Dunnett's t-test to isolate the differences)]. Reboxetine showed a good efficacy, safety and tolerability in PSD patients affected by "retarded" depression. We conclude that reboxetine is well tolerated and may be a useful therapeutic option in PSD patients with "retarded" depression.

Hypertension Associated with Citalopram

Objective:

To report a case of hypertension resulting from the therapeutic use of citalopram and review previous reports in the literature.

Case Summary:

An 87-year-old white woman who had taken a single dose of citalopram 20 mg presented to the hospital on the same day with hypertension (BP 200/100 mm Hg) following a presyncopal episode and headache. Citalopram was discontinued; the hypertension resolved in 24 hours and remained stable for 8 days. She had multiple systemic illnesses, including hypertension; however, they were under control, and no electrocardiogram abnormality shown at this time was different from previous recordings. No other medical or pharmacologic cause was found for the adverse reaction.

Discussion:

The manufacturer reports hypotension and bradycardia as being infrequent adverse effects of citalopram. To our knowledge, there have been no previous reports of hypertension after the first dose of citalopram. Multiple physical illnesses and drugs used may have interfered with findings obtained in this case. However, an acute increase in blood pressure after the first dose, which had been within normal levels with antihypertensive treatment for 4 years, as well as the low drug interaction profile of citalopram suggest that this adverse drug reaction was probable according to the Naranjo probability scale.

Conclusions:

Future research should address the cardiovascular and autonomic effects of selective serotonin reuptake inhibitors, including citalopram, in the older population and in persons with any known heart disease. Citalopram should be used with care in elderly patients unless more data are obtained from well-designed studies.

Drug Therapy in Transplant Recipients

Elderly patients with end-stage organ failure are now more frequently undergoing transplantation. Medication management in this population is challenging because of the combination of multiple comorbidities, polypharmacy, and immunological, pharmacokinetic and pharmacodynamic changes attributable to the aging process. Immunosuppressive medications can exacerbate pre-existing medical conditions and promote the development of disease processes. Cardiovascular disorders, such as hypertension, coronary artery disease, congestive heart failure and arrhythmias are common in elderly transplant recipients, and account for most of the deaths in this population. Blood pressure, blood glucose and cholesterol control is of particular concern because elderly transplant recipients frequently have or develop these complications. Elderly transplant recipients are commonly receiving anticoagulation therapy with warfarin and are at a higher risk of bleeding, especially if they have renal dysfunction. Infectious complications occur frequently in the transplanted population, with pneumonia being the most common infection seen in hospitalised patients. Attention to vaccination for the prevention of influenza and pneumococcal infections is important because of the increased risk of these diseases in this population. Depression itself has been associated with decreased survival in older individuals, and depression in elderly transplant recipients may be reversible with the administration of pharmacological agents. Effective long-term care of transplant recipients demands an understanding of how particular medications affect clinical evaluation and treatment. This article addresses some of the practical issues surrounding medication management and prevention of these particular problems in elderly transplant recipients.

Use of citalopram in pervasive developmental disorders

This study assessed the effectiveness and tolerability of the selective serotonin reuptake inhibitor citalopram in the treatment of patients with pervasive developmental disorders (PDDs). The medical charts of 15 children and adolescents (aged 6-16 yr) with Asperger syndrome, autism, or PDD not otherwise specified treated with citalopram were retrospectively reviewed. The final dose of citalopram was 16.9 +/- 12.1 mg/day with a treatment duration of 218.8 +/- 167.2 days. Independent ratings of the Clinical Global Impression (CGI) Severity and Improvement scales allowed comparison between baseline and PDD symptoms at the last visit. Eleven adolescents (73%) exhibited significant improvement in PDD, anxiety, or mood CGI score (z = 2.95; p =.003). Anxiety symptoms associated with PDDs improved significantly in 66% of patients (z = 2.83, p =.005), and mood symptoms improved significantly in 47% of patients (z = 2.78, p =.005). Mild side effects were reported by five patients (33%). These data suggest citalopram may be effective, safe, and well tolerated as part of the treatment of PDDs.

Naturalistic study of the early psychiatric use of citalopram in the United States

We obtained information on the efficacy and safety of citalopram in settings that resemble actual clinical practice. A total of 1,783 patients participated in this open, uncontrolled, naturalistic Phase IV evaluation of citalopram at 447 U.S. investigative sites. Participants were selected by guidelines in the citalopram package insert using minimal exclusion criteria. Citalopram dosing began at 20 mg/day and could be titrated to 60 mg/day. Outcomes included the Clinical Global Impressions-Improvement scale (CGI-I) and a Patient Global Evaluation. Separate analyses were performed on patients with a primary diagnosis of major depressive disorder (MDD) (76%) who reported intolerance or nonresponse to previous selective serotonin reuptake inhibitors (SSRIs). Patients included tended to have treatment-resistant or intolerant, chronic or recurrent, comorbid depression with a mean duration of illness of 10 years. At study completion, more than 68% of treatment completers were classified as responders (CGI-I score of 1 or 2). Endpoint analyses showed response rates of 54% in all patients, 56% in patients with MDD, 49% in SSRI nonresponsive patients, and 53% in patients with a history of SSRI intolerance. Nausea (9.8%) and headache (7.3%) were the most often reported adverse events. Patients with a history of SSRI intolerance had a discontinuation rate of 21.8%, whereas those without such a history had a discontinuation rate of 13.3%. Citalopram administered at an average dose of 23.6 mg/day was associated with favorable outcomes and was generally well tolerated.

Changes in human in vivo serotonin and dopamine transporter availabilities during chronic antidepressant administration

Few studies have demonstrated in vivo alterations of human serotonin and dopamine transporters (SERTS and DATS) during antidepressant treatment. The current study measured these transporter availabilities with [(123)I]beta-CIT single photon emission computed tomography (SPECT) during administration of selective serotonin reuptake inhibitors (SSRIs) or a non-SSRI, bupropion. A total of 17 healthy human subjects were randomly assigned to two different treatment protocols: (1). citalopram (40 mg/day) followed by augmentation with bupropion (100 mg/day) or (2). bupropion (100-200 mg/day) for 16 days. Citalopram significantly inhibited [(123)I]beta-CIT binding to SERT in brainstem (51.4%) and diencephalon (39.4%) after 8 days of administration, which was similarly observed after 16 days. In contrast, citalopram significantly increased striatal DAT binding by 15-17% after 8 and 16 days of administration. Bupropion and its augmentation to citalopram did not have a significant effect on DAT or SERT. In 10 depressed patients who were treated with paroxetine (20 mg/day), a similar increase in DAT and inhibition of SERT were observed during 6 weeks treatment. The results demonstrated the inhibition of SERT by SSRI in human in vivo during the chronic treatment and, unexpectedly, an elevation of DAT. This apparent SSRI-induced modulation of the dopamine system may be associated with the side effects of these agents, including sexual dysfunction.

A retrospective study of citalopram in adolescents with depression

Recent evidence suggests that the selective serotonin reuptake inhibitors are safe and efficacious in treating juveniles with depression. However, citalopram has not been reported in adolescents with depression. This study assessed the effectiveness and tolerability of citalopram in all adolescents with depressive disorders treated naturalistically in a community mental health center during a 1-year interval. Medical charts were retrospectively reviewed for 21 adolescents treated with citalopram for major depression (n = 14), bipolar depression (n = 4), or dysthymia (n = 3). An independent rater compared last visit to baseline depression using the Clinical Global Impression (CGI) Severity and Improvement scales. Adolescents received citalopram for an average of 128.5 +/- 84 days at a final average dose of 26.5 +/- 13.1 mg/day. Sixteen of these 21 adolescents (76%) exhibited much to very much improvement as measured by the CGI, and severity of depression diminished significantly (z = 3.007, p < 0.0026). Mild side effects, including headaches, dizziness, nausea, sedation, agitation, and sweating were reported by 7 (33%) of the patients. These data suggest that citalopram may be effective, safe, and well tolerated in the treatment of adolescents with depressive disorders and that controlled trials are warranted in this population.

Citalopram-induced bradycardia and presyncope

OBJECTIVE

To report a case of symptomatic bradycardia and hypotension that resulted from the therapeutic use of citalopram and to review any previous reports in the literature, from the manufacturer, and the Australian Drug Reaction Advisory Committee (ADRAC).

CASE SUMMARY

A 60-year-old white woman who had been taking citalopram 20 mg/d for two weeks presented to the hospital with a heart rate of 39 beats/min, mild hypotension (systolic BP 105 mm Hg), and a normal electrocardiogram (QTc < 440 msec), following a presyncopal episode. The patient was admitted for cardiac monitoring, and citalopram was discontinued. The bradycardia and hypotension resolved in the 48-hour period following cessation of citalopram. No other medical or pharmacologic cause was found for the adverse drug reaction.

DISCUSSION

Bradycardia has been reported rarely with citalopram in therapeutic doses, but this is the first detailed case with a dose of only 20 mg. The manufacturer reports bradycardia as an infrequent adverse effect (0.1-1%) of citalopram. There have been no reports to ADRAC or to the manufacturer in postmarketing surveillance. There is a case report of asymptomatic bradycardia in a patient whose dose was increased to 40 mg. In the case reported here, there was no QTc prolongation consistent with previous reports. The sinus bradycardia reported more often with therapeutic doses would appear to be distinct to QT abnormalities seen with citalopram overdose.

CONCLUSIONS

Citalopram should be used with care in the elderly and in persons with a history of heart disease. Heart rate and blood pressure should be monitored in the first week of therapy and when doses are modified.