Mianserin, a 5-HT2 receptor antagonist, in the treatment of delirium: an open study

Trazodone and Mianserin for Delirium: A Retrospective Chart Review

BACKGROUND

Although antipsychotics are commonly used for delirium, their adverse effects are a serious concern in light of extrapyramidal symptoms and cardiovascular disturbances. In clinical practice, sedative antidepressants are frequently used as an alternative treatment for delirium; however, there is scarce evidence. Thus, we conducted a retrospective chart review to examine the use and effectiveness of trazodone and mianserin for delirium.

METHODS

Patients who were admitted to a university hospital during 4 years and received either trazodone or mianserin on a regular schedule as monotherapy for the treatment of delirium were included. The rates of and times to the improvement of delirium were compared.

RESULTS

Among 3971 patients who developed delirium, 379 (9.5%) and 341 (8.6%) patients received trazodone and mianserin on a regular schedule; 52 and 46 patients met the eligibility criteria (ie, monotherapy) for trazodone and mianserin, respectively. The percentages of patients 65 years or older were 86.5% (n = 45) for trazodone and 89.1% (n = 41) for mianserin. The rates of the improvement of delirium were 63.5% for trazodone and 50.0% for mianserin. Times to the improvement of delirium were 5.3 days (95% confidence interval, 3.2-7.4 days) for trazodone and 9.3 days (95% confidence interval, 5.3-13.3 days) for mianserin. There were no significant differences in the primary outcomes between the 2 groups ( P = 0.17 and P = 0.13, respectively).

CONCLUSION

Considering potentially serious, sometimes lethal, adverse effects of antipsychotics, sedative antidepressants such as trazodone and mianserin may be a treatment option for delirium, especially in the elderly.

Neuroprotective effects of HTR1A antagonist WAY-100635 on scopolamine-induced delirium in rats and underlying molecular mechanisms

BACKGROUND

Limited surveys have assessed the performance of 5-hydroxytreptamine receptor 1A and its antagonist WAY-100635 in pharmacological manipulations targeting delirium therapies. The purpose of this paper was to assess the central pharmacological activity of WAY-100635 in a rat model of scopolamine-induced delirium and its underlying mechanism.

RESULTS

A delirium rat model was established by intraperitoneal injection of scopolamine and behavioral changes evaluated through open field and elevated plus maze experiments. Concentrations of monoamines in the hippocampus and amygdalae were detected by high performance liquid chromatography. The effect of WAY-100635 on the recovery of rats from delirium was assessed by stereotactic injection of WAY-100635 and its mechanism of action determined by measuring mRNA and protein expression via real time PCR and western blotting methods. The total distance and the number of crossing and rearing in the elevated plus maze test and the time spent in the light compartment in the dark/light test of scopolamine-treated rats were significantly increased while the percentage of time spent in the open arms was decreased, showing the validity of the established delirium rat model. The measurement of the concentrations of noradrenaline, 3,4-dihydroxyphenylacetic acid, the homovanillic acid, 5-hydroxy-3-indoleacetic acid and serotonin concentrations in the cerebrospinal fluid (CSF) of scopolamine-induced delirium rats were significantly increased. The intra-hippocampus and intra-BLA injections of WAY-100635 improved the delirium-like behavior of rats by significantly reducing the expression of NLRP3 inflammasome and the release of IL1-β and IL8 into CSF.

CONCLUSIONS

Taken together, these findings indicate that WAY-100635 may exert a therapeutic effect on post-operative delirium by controlling neurotransmission as well as suppressing neuroinflammation in the central nervous system.

The pharmacokinetics of mianserin suppositories for rectal administration in dogs and healthy volunteers: a pilot study

BACKGROUND

We formulated mianserin suppositories for the treatment of delirium and evaluated their pharmacokinetics by measuring plasma drug concentrations in dogs and healthy human volunteers.

METHODS

Mianserin suppositories were prepared by a melting technique using Tetramide® tablets and Witepsol H-15 as the suppository base. Pharmacokinetics of this 30-mg mianserin preparation were evaluated in three beagle dogs and three healthy adult males, in line with ethics committee approval. Plasma mianserin levels were determined using gas chromatography-mass spectrometry.

RESULTS

In dogs, the maximum plasma mianserin concentration (Cmax) was 1.3 ± 0.4 ng/mL, the time to Cmax (tmax) was 5.5 ± 4.3 h, and the area under the plasma concentration-time curve from 0 to 24 h (AUC0-24) was 18.9 ± 1.9 h・ng/mL. In humans, the Cmax was 14.6 ± 6.3 ng/mL, the tmax was 8 h, and the AUC0-24 was 266 ± 103 h・ng/mL.

CONCLUSIONS

The current study characterized the pharmacokinetics of mianserin suppositories in dogs and humans. As compared to oral administration, the suppositories produced a lower Cmax and a delayed tmax, although AUC0-24 values were comparable. It will be necessary to identify an appropriate dose that produces an adequate plasma mianserin concentration for effective and safe clinical use.

TRIAL REGISTRATION

UMIN000013853.

5-HT(1A) receptor antagonist improves behavior performance of delirium rats through inhibiting PI3K/Akt/mTOR activation-induced NLRP3 activity

Postoperative delirium is a common complication that often results in poor outcomes in surgical and elderly patients. Accumulating evidences suggest that the pathophysiology of delirium results from multiple neurotransmitter system dysfunctions. To further clarify the effects of the selective serotonin (5-HT) (1A) antagonist WAY-100635 on the behaviors in scopolamine induced-delirium rats and to explore the molecular mechanism, in this study, we investigated the change of monoamine levels in the cerebrospinal fluid (CSF) and different brain regions using high-performance liquid chromatography and assessed the behavioral retrieval of delirium rats treated with WAY-100635. It was found that 5-hydroxy-3-indoleacetic acid (5-HIAA), 3,4-dihydroxyphenylacetic acid, and homovanillic acid concentrations in the CSF of scopolamine-induced delirium rats were significantly increased, among which 5-HIAA was also increased in hippocampus and basolateral amygdala (BLA), and 5-HT(1A) receptor was significantly higher in the hippocampuses and BLA than other brain regions. Furthermore, intrahippocampus and intra-BLA stereotactic injection of WAY-100635 improved the delirium-like behavior of rats. Mechanistically, after WAY-100635 treatment, significant reduction of IL-1β release into CSF and NOD-like receptor family, pyrin domain containing 3 (NLRP3) expression, phosphorylated phosphatidylinositol-3-kinase (PI3K), protein kinase B (AKT), and S6K was observed. Altogether, these results suggest that delirium rats induced by scopolamine may be correlated with an increased cerebral concentration of 5-HT and dopamine neurotransmitters system; the selective 5-HT(1A) antagoniszts can reverse the delirium symptoms at some extent through tendering PI3K/Akt/mammalian target of rapamycin complex 1 (mTOR) activation-induced NLRP3 activity and then reducing IL-1β release.

Efficacy of mianserin on symptoms of delirium in the aged: an open trial study

1. The authors administered the tetracyclic antidepressant mianserin to aged patients with delirium to examine its efficacy in delirium. 2. The subjects were 62 consecutive aged patients with delirium, diagnosed according to DSM-IV. 3. The patients' symptoms of delirium were assessed once a week over the 4-week study period using the Delirium Rating Scale. 4. It was found that mianserin was effective, especially in treating behavioral and sleep-wake disturbance and that it was almost free from undesirable side-effects. It appears to be particularly useful for elderly patients with delirium, who easily develop extrapyramidal side-effects when given antipsychotic drugs. These properties of mianserin are worthy of further study.