Sensitive method for the simultaneous measurement of fluphenazine decanoate and fluphenazine in plasma by high-performance liquid chromatography with cuolometric detection

A highly sensitive and specific high-performance liquid chromatographic method with coulometric detection was developed for the simultaneous assay of fluphenazine decanoate and fluphenazine in plasma. The extraction and sample clean-up procedures are simple, rapid to execute, yet yield chromatograms relatively free of any interference from endogenous plasma constituents, such that the extraordinary sensitivity of the coulometric detector can be exploited fully. This is the first analytical procedure for the simultaneous determination of fluphenazine decanoate and fluphenazine. The detection limits for both fluphenazine decanoate and fluphenazine were 0.1 ng/ml plasma and the limits of quantitation were 0.25 ng/ml plasma. Standard curves from 0.25 to 10 ng/ml were linear with coefficients of variation <10%. The method was applied to measure plasma levels of fluphenazine decanoate and fluphenazine in patients under medication with 25–50 mg biweekly intramuscular (i.m.) injections of fluphenazine decanoate. It was possible to monitor the plasma levels of fluphenazine in all cases. Fluphenazine decanoate was present in measurable concentration in the plasma of 4 out of 5 patients who received biweekly i.m. injections of 50 mg fluphenazine decanoate. In a pilot experiment with a dog, the method was used to follow fluphenazine decanoate and fluphenazine plasma levels up to 13 days, at least, after i.m. single dose (10 mg/kg).     

Outpatient Maintenance of Chronic Schizophrenic Patients with Long-acting Fluphenazine: Double-blind Placebo

A double-blind placebo trial of fluphenazine decanoate, a long-acting phenothiazine, was carried out to determine its value in maintenance therapy of chronic schizophrenic outpatients already established on the drug for a minimum period of eight weeks. In low doses it was significantly more effective than placebo in preventing relapse and admission to hospital. Relapse was accompanied by a resurgence of specifically schizophrenic symptoms and by an increase in abnormalities described by the relatives. There was no difference between the experimental and control groups in the treatment required for depression. The group on active medication required more treatment for Parkinsonism, but this difference did not reach statistical significance.In the context of a well-run special clinic for outpatient follow-up of chronic schizophrenic patients these results confirm the usefulness of long-acting fluphenazine. By inference, the benefit of this treatment highlights the need for adequate community services to deal with the residual chronic disabilities which are characteristic of these patients.     

Differential effects of acute and chronic treatment with typical and atypical neuroleptics on c-fos mRNA expression in rat forebrain regions using non-radioactive in situ hybridization.

The regional difference in the expression of c-fos mRNA in rat forebrain after either acute or chronic administration of typical (haloperidol and fluphenazine) and atypical neuroleptics (clozapine and (+/-)-sulpiride) was investigated. Rats were injected intraperitoneally with vehicle or neuroleptics daily for 14 days. Twenty-four hours after the last injection, the rats were challenged with vehicle or neuroleptics. C-fos mRNA expression was determined by non-radioactive in situ hybridization. Acute treatment with typical neuroleptics induced a remarkable induction of c-fos mRNA in the dorsolateral striatum, whereas this induction was greatly attenuated by chronic administration. All neuroleptics examined induced c-fos mRNA in the shell region of N. accumbens by acute administration and this expression was still elevated after chronic treatment. Since chronic neuroleptics do not induce tolerance to their antipsychotic activities, our study suggests that the shell region of N. accumbens is an important target site for antipsychotic effects of neuroleptics.     

Antimutagenic activity of new analogues of fluphenazine

Fluphenazine (FPh) exhibited antimutagenic activity in lymphocyte cultures, markedly decreasing genotoxic effects of standard mutagenic agents present in cell cultures. However, the strong pharmacological activity of this neuroleptic drug, together with its serious side effects on the central nervous system, limits its use as an antimutagenic compound. In this paper we describe a route of chemical synthesis of FPh analogues that are more hydrophilic than the model compound, thus probably penetrate more weakly through the blood-brain barrier. These new analogues were tested for their antimutagenic and pro-apoptotic activities in human lymphocyte cultures, genotoxically damaged in vitro with benzo[a]pyrene [40 microM, 30 min] and subsequently cultured for 48 h in the presence of the tested compounds. The fluphenazine analogues enhanced apoptosis in genotoxically damaged lymphocytes more strongly than the model compound did. The increase of apoptotic cell frequency was the highest with compound 4a [2-(trifluoromethyl)-10-[3-(diethanolamino)-2-hydroxypropyl] phenothiazine]--a 35% higher effect than that of fluphenazine. The cytotoxicity of derivative 4a was the lowest among the tested compounds; it was 60% lower than that of fluphenazine. The antimutagenic effect of 4a was about 10% stronger than that of fluphenazine. Compound 4a also had the highest hydrophilicity of the new FPh analogues. Compound 4a was chosen for further study as a potentially usable antimutagen that would only weakly penetrate the central nervous system.     

Decreased antistereotypic effect of neuroliptics after additional treatment with a benzodiazepine, a GABA agonist or an anticholinergic compound.

Neuroleptics are very potent antagonists against stereotypies induced by DA-stimulants including methylphenidate. This effect of neuroleptics is usually related to the antipsychotic effect of these compounds. In contrast we found that GABA agonists potentiate stereotyped gnawing induced by methylphenidate. The GABA agonist muscimol in combination with neuroleptics will attenuate the antagonistic effect of these compounds on stereotyped gnawing induced by methylphenidate. However a differentiation between the neuroleptic drugs was found: Haloperidol, spiroperidol and pimozide were profoundly antagonized by muscimol whereas cis(Z) - flupenthixol and fluphenazine were less antagonized. Baclofen shows no significant effect. Diazepam and scopolamine also strongly antagonized the antistereotypic effect of the butyrophenone-like compounds whereas only scopolamine could antagonize fluphenazine and cis(Z) - flupenthixol. Therefore we conclude that if the antistereotypic effect of neuroleptics correlates to the antipsychotic effect, a GABA agonist would probably not potentiate the antipsychotic effect of neuroleptics but rather antagonize it.     

Systemic relaxin in pregnant pony mares grazed on endophyte-infected fescue: effects of fluphenazine treatment

Tall fescue is one of the most widely grown forage grasses for horses in the United States. However, it is frequently infected with the endophyte Neotyphodium coenophialum which produces ergot alkaloids that cause severe adverse effects in the pregnant mare. The objectives of this study were to determine the effects of fescue toxicosis and fluphenazine on circulating relaxin in pregnant pony mares and evaluate the usefulness of relaxin as a monitor of treatment efficacy. Twelve mares were maintained on endophyte-infected tall fescue pasture. Group TRT (n = 6), received 25 mg of fluphenazine decanoate (i.m.) on Day 320 of gestation while Group UTRT served as untreated controls. Daily blood samples were collected from Day 300 of gestation until Day 3 post partum and analyzed for plasma relaxin concentrations using a homologous equine radioimmunoassay. Mean gestation lengths were 330 +/- 0.7 and 336.5 +/- 3.2 days for TRT and UTRT mares, respectively (P = 0.07). Mean plasma relaxin concentrations in both groups of mares during the week before treatment (Day 313 to 319) were not different (UTRT, 53.4 +/- 11.3 ng/mL; TRT, 61.4 +/- 9.3 ng/mL). In the week after treatment (Day 320 to 326), mean plasma relaxin tended to be higher (P = 0.1) in TRT mares (66.7 +/- 6.2 ng/mL) when compared with UTRT mares (49.6 +/- 6.6 ng/mL), representing a 17.1 ng/mL difference in circulating relaxin between the two groups. Systemic relaxin during the last week before delivery (days relative to parturition) for UTRT and TRT mares was 45.7 +/- 6.7 and 64.7 +/- 6.4 ng/mL (P = 0.06), respectively. At Day -8 and Day -5 relative to parturition, systemic relaxin in TRT mares was significantly higher (P < 0.05) than in UTRT mares. Three of the six UTRT mares and one TRT mare showed clinical symptoms of fescue toxicosis. In the week before delivery, circulating relaxin in mares with problematic pregnancies (39.9 +/- 7.8 ng/mL) was significantly lower than concentrations measured in mares with normal pregnancies (63.4 +/- 5.4 ng/mL; P = 0.03). Clinical observations suggest that a one-time injection with fluphenazine improved pregnancy outcome by reducing the adverse effects of fescue toxicosis concomitant with a stabilization of plasma relaxin concentrations. These data support the hypothesis that systemic relaxin may be a useful biochemical means of monitoring placental function and treatment efficacy in the mare.     

Controlled trial of Penfluridol in Acute Psychosis

A controlled study was made of penfluridol medication consisting of a single weekly oral dose of 30 mg in 30 patients with acute psychoses of varying type and origin. This medication was found to be effective. No significant side effects occurred.Several long-acting neuroleptics for injection are now available. The development of an oral compound of this type is an asset because of the manageability of the oral drug in the hands of family doctors and social psychiatrists.     

Severe Depressive Mood Changes Following Slow-release Intramuscular Fluphenazine Injection

Sixteen patients in whom schizophrenia was initially diagnosed and who were treated with fluphenazine enanthate or decanoate developed severe depression for a short period after the injection. In five cases this depression is thought to have been responsible for suicide. In 8 out of 10 cases the depression responded to electroplexy (E.C.T.). It is recommended that patients who are treated with fluphenazine should be carefully supervised.     

Pharmacological effects of a specific dopamine D-1 antagonist SCH 23390 in comparison with neuroleptics

Neuroleptics such as thioxanthenes (cis($\text{Z}$)-flupentixol and cis($\text{Z}$)-clopenthixol) and phenothiazines (fluphenazine and perphenazine), which block both dopamine (DA) D-1 and D-2 receptors and the butyrophenones (haloperidol and spiroperidol), which block D-2 receptors only, are equipotent both behaviorally and clinically. A new compound SCH 23390 which selectively blocks DA D-1 receptors, resembles many neuroleptics in its pharmacological profile: antistereotypic effects in mice, rats and dogs, cataleptogenic effect and inhibitory effect on amphetamine circling. In contrast SCH 23390 has no effect on apomorphine-induced vomiting in dogs and little effects on 6-OHDA-denervated supersensitive DA receptors, stimulated by the DA agonist 3-PPP. In a series of experiments where methylphenidate-induced stereotyped gnawing in mice was inhibited by neuroleptics, it was shown that concomitant treatment with scopolamine or diazepam attenuated the effect of butyrophenones (D-2 antagonists). The same treatment attenuated the effect of phenothiazines, to a lesser extent, and hardly attenuated the effect of thioxanthenes and SCH 23390 at all. It is concluded that DA D-1 receptors are as important as D-2 receptors for the expression of neuroleptic activity in most animal models believed to be predictive of antipsychotic and extrapyramidal side-effect potential. However, the D-1 antagonist is less sensitive than D-2 antagonists to antimuscarinic compounds and benzodiapines.     

Neuroleptics Up-Regulate Adenosine A2a Receptors in Rat Striatum: Implications for the Mechanism and the Treatment of Tardive Dyskinesia

Abstract: Neuroleptics, which are potent dopamine receptor antagonists, are used to treat psychosis. In the striatum, dopamine subtype-2 (D₂) receptors interact with high-affinity adenosine subtype-2 (A_2a) receptors. To examine the effect of various neuroleptics on the major subtypes of striatal dopamine and adenosine receptors, rats received 28 daily intraperitoneal injections of these drugs. Haloperidol (1.5 mg/kg/day) increased the density of striatal D₂ receptors by 24% without changing their affinity for [³H]sulpiride. Haloperidol increased the density of striatal A_2a receptors by 33% (control, 522.4 ± 20.7 fmol/mg of protein; haloperidol, 694.6 ± 23.6 fmol/mg of protein; p < 0.001) without changing their affinity for [³H]CGS-21680 (control, 19.2 ± 2.2 nM; haloperidol, 21.4 ± 2.3 nM). In contrast, haloperidol had no such effect on striatal dopamine subtype-1 (D₁) and adenosine subtype-1 (A₁) receptors. Binding characteristics and the pharmacological displacement profile of the increased [³H]CGS-21680 binding sites confirmed them as A_2a receptors. Comparing different classes of neuroleptics showed that the typical neuroleptics haloperidol and fluphenazine (1.5 mg/kg/day) increased D₂ receptor densities, whereas the atypical neuroleptics sulpiride (100 mg/kg/day) and clozapine (20 mg/kg/day) did not (control, 290.3 ± 8.7 fmol/mg of protein; haloperidol, 358.1 ± 6.9 fmol/mg of protein; fluphenazine, 381.3 ± 13.6 fmol/mg of protein; sulpiride, 319.8 ± 18.9 fmol/mg of protein; clozapine, 309.2 ± 13.7 fmol/mg of protein). Similarly, the typical neuroleptics increased A_2a receptor densities, whereas the atypical neuroleptics did not (control, 536.9 ± 8.7 fmol/mg of protein; haloperidol, 687.9 ± 28.0 fmol/mg of protein; fluphenazine, 701.1 ± 31.6 fmol/mg of protein; sulpiride, 563.3 ± 27.2 fmol/mg of protein; clozapine, 550.9 ± 40.9 fmol/mg of protein). There were no differences in affinities for [³H]CGS-21680 or [³H]sulpiride among the various treatment groups. This study demonstrates that typical neuroleptics induce comparable up-regulation in both striatal D₂ and A_2a receptors. Thus, A_2a receptors might be a pharmacologic target for the development of novel therapeutic strategies to minimize the adverse effects of antipsychotic treatment.     

Absence of noxious effects of selected neuroleptics in dominant-lethal mutagenesis assay.

In a dominant-lethal assay in mice the following tricyclic neuroleptics were tested: prothiaden, imipramine, oxyprothepin decanoate and docloxythepin. No dominant-lethal effect was induced by these neuroleptics, even when administered at doses many times as great as clinical doses. The reduced percentages of pregnancies, in females who had copulated with males receiving docloxythepin, observed during and immediately after its administration, were directly connected with marked sedation induced in the males by this neuroleptic.     

Depolarisation-Dependent Protein Phosphorylation in Rat Cortical Synaptosomes Is Inhibited by Fluphenazine at a Step After Calcium Entry

Abstract: The sequence of molecular events linking depolarisation-dependent calcium influx to calcium-stimulated protein phosphorylation is unknown. In this study the effect of the neuroleptic drug fluphenazine on depolarisation-dependent protein phosphorylation was investigated using an intact postmitochondrial pellet isolated from rat cerebral cortex. Fluphenazine, in a dose-dependent manner, completely inhibited the increases in protein phosphorylation observed previously. The concentration of fluphenazine required for 50% inhibition varied for different phosphoproteins but for synapsin I was 123 μ M. Other neuroleptics produced effects similar to fluphenazine with their order of potency being thioridazine > haloperidol > trifluoperazine > fluphenazine > chlorpromazine. Fluphenazine also increased the phosphorylation of proteins in nondepolarised controls at concentrations of 20 and 60 μ M. The inhibition of depolarisation-dependent phosphorylation was apparently not due to a loss of synaptosomal integrity or viability, a decrease in calcium uptake, a change in substrate availability, or to a change in protein phosphatase activity. The data are most consistent with an inhibition of protein kinase activity by blockade of calmodulin or phospholipid activation.     

Neuroleptic-induced oral movements in rats: methodological issues

In three separate experiments groups of rats were chronically administered neuroleptics in a variety of ways (chronic injections, subcutaneous implants, and decanoate injections) and examined for oral movements (OMs) in two different tests: in an open cage using a human observer, or in a plexiglas tube enclosure, where OMs were monitored both by a human observer and computerized video analysis system. These two testing methods showed different effects of neuroleptic administration. In the open cage, OMs tended to be enhanced during chronic neuroleptic exposure and to rapidly subside upon drug withdrawal. The enhanced OMs were especially present just after drug injections, when activity levels were low. In the observation tube environment, however, OMs tended to be low soon after drug treatments, and elevated upon withdrawal. Thus, the type of behavioral test used determines how neuroleptic-induced increases in oral activity should be interpreted.     

Comparison of the effects of substituted benzamides and standard neuroleptics on the binding of 3H-spiroperidol in the rat pituitary and striatum with in vivo effects on rat prolactin secretion.

The abilities of sulpiride, metoclopramide, clozapine, loxapine, chlorpromazine, thioridazine, fluphenazine, haloperidol, (+)-butaclamol and RMI 81,582 to displace ³H-spiroperidol from rat pituitary and striatal membranes in vitro were compared to their abilities to stimulate rat prolactin secretion in vivo. There was a significant correlation between the abilities of clozapine, chlorpromazine, thioridazine, fluphenazine, RMI 81,582, haloperidol and (+)-butaclamol to bind to pituitary and striatal spiroperidol binding sites and to stimulate rat prolactin secretion. Loxapine was somewhat more potent and sulpiride and metoclopramide were markedly more potent in their abilities to stimulate prolactin secretion than would be predicted on the basis of their abilities to bind to pituitary dopamine receptors as measured by antagonism of ³H-spiroperidol binding. The abilities of metoclopramide and sulpiride to increase prolactin secretion and to produce anti-psychotic and extrapyramidal effects may be mediated by action at dopamine receptors which differ from those at which classical neuroleptics act, and they may also be mediated by non-dopaminergic mechanisms. Potency as inhibitors of ³H-neuroleptic binding in the rat pituitary or striatum appears to have heretofore unappreciated limitations to predict physiological functions such as prolactin stimulation and anti-psychotic activity.     

Neuroleptic-induced dopamine hyposensitivity

In contrast to dopaminergic hypersensitivity induced by most neuroleptic drugs including fluphenazine, thioridazine induced hyposensitivity to subsequent apomorphine stereotypy in rats. The difference between thioridazine and fluphenazine may relate in part to anticholinergic properties of thioridazine, but appears to involve additional mechanisms. Differences in dopaminergic sensitization may be important to the management and prevention of tardive dyskinesia an iatrogenic disorder associated with chronic exposure to neuroleptics.     

Effect of neuroleptics and antidepressants on the process of gamma-aminobutyric acid-H3 uptake by isolated rat brain nerve endings]

The effects of phenothiazine neuropleptics--chlorpromazine, trifluoperazine, fluphenazine and of antidepressants-imipramine and phthoracizine on the GABA-H3 accumulation by synaptosomes of the rat cerebral cortex were studied. All neuroleptics were found to inhibit the process of neurotransmitter uptake by the brain synaptosomes. Antidepressants were less potent. Chlorpromazine had the highest inhibitory effect on GABA uptake and phthoracizine--the lowest. It is suggested that the influence of neurolptics on GABA uptake could play a certain role in the mode of a synaptic action of these drugs.     

High-performance liquid chromatographic determination of pipotiazine in human plasma and urine

A high-performance liquid chromatographic method has been developed for the determination of pipotiazine in human plasma and urine. After selective extraction, pipotiazine and the internal standard (7-methoxypipotiazine) are chromatographed on a column packed with Spherosil XOA 600 (5 μm) using a 7:3 (v/v) mixture of diisopropyl ether—isooctane (1:1, v/v) + 0.2% triethylamine and diisopropyl ether—methanol (1:1, v/v) + 0.2% triethylamine + 2.6% water. The eluted compounds are measured by fluorescence detection. The sensitivity of the method was established at 0.25 ng/ml pipotiazine in plasma and 2 ng/ml pipotiazine in urine (C.V. < 5%). The method has been successfully applied to a pharmacokinetic study following a single oral administration of 10 mg of pipotiazine.