Acute neuroleptic treatment in elderly patients without dementia

Low doses of neuroleptics are the standard for treating psychosis in elderly patients because of concern about inducing adverse effects. The authors found that fixed, low-dose neuroleptic treatment (0.15 mg/kg/day) for 10 days resulted in low perphenazine levels and low rates of acute response (25%) in elderly patients with primary psychotic illness (without dementia). Increase in initial dose did not speed acute response and induced adverse effects that were absent or minimal with low-dose treatment. With higher-dose treatment, drug blood levels rose disproportionately, and level-to-dose ratios were higher than those observed in non-elderly adults. Naturalistic follow-up suggested that response may take longer to develop than in non-elderly adults and that low doses for a longer duration may provide effective treatment.

Psychotogenic drug use and neuroleptic response

When fixed doses of haloperidol or perphenazine were used in two separate studies, we found that psychotic males with a prior history of psychotogenic drug use had a poorer early neuroleptic response even in the early stages of their psychotic disorder than psychotic males who had not previously used significant amounts of psychotogenic drugs. Relative neuroleptic refractoriness may be characteristic of some dual diagnosis patients at the beginning of their illness. Antecedent psychotogenic drug use may contribute to the development of psychosis and to relative neuroleptic refractoriness by means of effects upon dopaminergic mechanisms.

Effects of lamotrigine on behavioral and cardiovascular responses to cocaine in human subjects

We evaluated the effects of acute pretreatment with lamotrigine, a putative glutamate release inhibitor, on the physiological and behavioral responses to intranasal cocaine in cocaine-dependent volunteers (N = 8). The study employed a double-blind, placebo-controlled, within-subject design. Subjects participated in six experimental sessions. On each study day, placebo, lamotrigine 125 mg, or lamotrigine 250 mg was administered orally in the morning, followed 2 hours later by intranasal cocaine 120 mg/70 kg or placebo. Measurements of heart rate and blood pressure were acquired, and subjects responded to mood state questionnaires at predetermined time intervals. Cocaine alone produced increases in heart rate, blood pressure, and several measures of pleasurable mood and drug effects. Lamotrigine alone produced a mild relaxing effect. Lamotrigine pretreatment altered neither the physiological responses nor the subjective ratings of cocaine's pleasurable or aversive mood effects.

Acquisition and maintenance of intravenous cocaine self-administration in Lewis and Fischer inbred rat strains

Lewis and Fischer inbred rat strains differ in behavioral and biochemical responses to psychoactive drugs: Lewis rats show greater behavioral responses to psychoactive drugs than Fischer rats and they fail to show biochemical adaptations in the mesolimbic dopamine system after chronic drug exposure, in contrast to Fischer and outbred rats. This suggests that Fischer and Lewis rats may differ in the initial, reinforcing effects of psychoactive drugs, but not in responses seen after the exposure that occurs with maintenance of drug-reinforced behavior. Thus, the present study tested whether these strains differ in acquisition or maintenance of intravenous cocaine self-administration. Acquisition of cocaine self-administration was examined in separate groups that were allowed 15 days to acquire the operant at one of three cocaine doses (0.25, 0.5, or 1.0 mg/kg/infusion). Compared to Fischer rats, Lewis rats acquired cocaine self-administration after fewer training trials and at lower doses. After maintenance, both strains showed characteristic extinction responding with saline substitution and dose-related responding to cocaine, although Fischer rats tended to show higher response rates. Finally, cocaine plasma levels, obtained after an intravenous cocaine infusion (1.0 mg/kg), showed no strain differences suggesting that the strain difference in acquisition was not due to cocaine pharmacokinetics. These strain differences in acquisition of cocaine self-administration may be related to reported strain differences in the mesolimbic dopamine system. Further, because acquisition of drug self-administration is an animal model of vulnerability to drug addiction, these inbred strains may be useful to study factors underlying such vulnerability.

Effect of alpha-methyl-para-tyrosine on response to cocaine challenge

This study evaluated the effect of an acute reduction in catecholamine synthesis produced by alpha-methyl-para-tyrosine (AMPT), a tyrosine hydroxylase inhibitor, on cocaine-induced euphoria. In a blinded, placebo-controlled study, AMPT (1 g p.o. T.I.D.) was given to 10 non-treatment-seeking cocaine abusers prior to intranasal administration of 2 mg/kg cocaine. AMPT, but not placebo, reduced plasma levels of the dopamine metabolite homovanillic acid and the norepinephrine metabolite 3-methoxy-4-hydroxyphenylglycol. AMPT also elevated prolactin levels, indicating inhibition of the tuberoinfundibular dopamine system. AMPT pretreatment produced a trend toward diminished cocaine "high" AMPT also tended to lower heart rate and blood pressure responses to cocaine, but had no effect on serum cocaine levels. Although we cannot rule out the therapeutic potential of the depletion strategy, our results with AMPT alone, at this dose, do not strongly support it.

Decreased digital flow persists after the abatement of cocaine-induced hemodynamic stimulation

This study determined whether the development of delayed ischemic sequelae due to cocaine use--after the return of arterial blood pressure (BP) and heart rate to near-baseline values--may be attributable to regional vasoconstriction which persists beyond the acute systemic hemodynamic response. Five cocaine-using volunteers received intravenous infusions of saline placebo and cocaine 0.50 mg/kg several days apart in a double-blinded cross-over design. The intensity and duration of the cocaine-induced decrease in peripheral blood flow (as documented by laser Doppler flowmetry of the finger) were compared to the increases in BP (obtained with a Dinamap) and heart rate using paired t-test and repeated-measures analysis of variance. A significant increase in BP and a significant decrease in finger flow were noted by the first time point (5 min). Within 15 min, cocaine induced a 36% +/- 5% increase in BP and a 73% +/- 18% decline in finger flow (P < 0.05 for difference between percent change in BP and percent change in flow). Dinamap(systolic) and Dinamap(diastolic) returned to within 15% of baseline within 30 min, while finger flow remained more than 50% below baseline for the remainder of the 60-min study period (P < 0.05). Changes in heart rate paralleled those in BP. Except for isolated cases of documented coronary vasoconstriction in patients presenting with complications after cocaine use, this study is the first to document the persistence of cocaine-induced vasoconstriction of a sensitive vascular bed beyond the hypertensive response. It thus helps to explain the development of ischemic injury after cocaine use despite a stable rate-pressure product.

Sensitization to the locomotor activating effects of cocaine following cocaethylene-preexposure

The present study assessed the ability of cocaethylene to induce sensitization to the behavioral activating effects of cocaine in the male Sprague-Dawley rat. Preexposure to cocaethylene (15 or 25 mg/kg) significantly enhanced the locomotor activating effects of a subsequent cocaine (15 mg/kg) challenge injection. In addition, acute intraperitonecal administration at several doses (10, 15, or 25 mg/kg) confirmed previous reports of increased bioavailability of cocaine in brain and plasma relative to cocaethylene. These data are discussed in terms of previous work in which a significant augmentation of cocaine-induced locomotor activity was not observed following cocaethylene preexposure.

Pyrimethamine analysis by enzyme inhibition and HPLC assays

Pyrimethamine is an antiparasitic agent currently used for therapy of central nervous system toxoplasmosis, a disease seen with increasing frequency in association with the AIDS epidemic. Monitoring of pyrimethamine levels may be particularly important because patients may be treated with high doses of the drug for extended periods of time. The authors have developed and validated both a new enzyme inhibition assay that can be run on an automated analyzer and an improved high performance liquid chromatography (HPLC) method. The calibration range of both methods is 100 to 3,000 micrograms/L. Both demonstrate good linearity, specificity, and precision, and correlate well with one another (r = 0.99). The CVs of the enzyme inhibition assay were < or = 8.6% and those of the HPLC method were < or = 5.4%. No interference was noted for a variety of drugs likely to be used concomitantly with or in lieu of pyrimethamine with the exception of a minor interference from trimethoprim in the enzyme inhibition assay. The major advantage of the enzyme inhibition assay is its ease of automation. The major advantages of the HPLC assay are its precision and relative simplicity. These methods should facilitate therapeutic monitoring of pyrimethamine.

Cocaethylene: pharmacology, physiology and behavioral effects in humans

Comorbid abuse of cocaine and alcohol is a common occurrence. Cocaethylene, the ethyl ester of benzoylecgonine, is an active metabolite formed as a result of simultaneous use of these substances. In humans, the concurrent ingestion of cocaine and alcohol, with resulting cocaethylene formation, has been associated with enhanced subjective euphoria, increased heart rate and increased plasma cocaine concentration. These findings suggest that cocaethylene may play a role in the morbidity and mortality associated with concurrent cocaine/alcohol abuse. This placebo-controlled, double-blinded study examined the behavioral and physiological effects and pharmacokinetics of intranasal cocaethylene administration in humans (n = 8), using cocaine as a comparator. Cocaethylene administration resulted in a euphoria similar to that produced by cocaine, although the effects differed significantly over time. Subjects were unable to distinguish between equimolar doses of cocaine and cocaethylene, although cocaethylene appeared to be eliminated more slowly than cocaine. Cardiovascular effects of cocaethylene and cocaine were similar. These findings are considered in light of the epidemiology and possible consequences of cocaine and alcohol abuse.

Cocaine and cocaethylene: effects on extracellular dopamine in the primate

Cocaine and cocaethylene (a psychoactive metabolite of concurrent cocaine and ethanol consumption) were studied in the anesthetized vervet monkey. The ability of each to elevate extracellular DA in the caudate nucleus was assessed using microdialysis probes acutely lowered through chronic guide cannulae. Blood samples were also collected to determine plasma levels of the two drugs. Doses of 1.5 mumol/kg cocaine (equivalent to 0.5 mg/kg cocaine-HCl) and cocaethylene were administered intravenously. Microdialysis and blood samples were collected at 5-min intervals immediately following drug administration. Both drugs caused a maximal four-fold increase in extracellular DA during the 5- to 10-min period following drug administration. This is the first report of cocaine (and cocaethylene) induced alterations in extracellular DA in primates. The abilities of cocaine and cocaethylene to produce euphoria are being compared in ongoing clinical research studies. The potential use of these results for interpreting the neurochemical basis of any differences in those studies is discussed.

Desipramine treatment of major depression in patients over 75 years of age

The authors investigated the relationship of desipramine concentrations in plasma to response, side effects, and dose in depressed patients over 75 years of age to determine if these "very old" patients were unusually sensitive to treatment. Thirty-four elderly patients consecutively hospitalized for nonpsychotic, unipolar major depression were treated with a fixed dose desipramine regimen for 4 weeks. Twelve nonresponding patients received a second trial at an increased dose. Comparisons were made with data from younger patients previously published by the authors. At comparable doses, steady-state desipramine concentrations in plasma in the elderly patients did not differ from those observed in younger patients. Response at levels in blood < 115 ng/ml was low, only 6 (21%) of 28 patient trials resulted in response. At levels > or = 115 ng/ml, 6 (46%) of 13 patient trials were effective. These rates were not significantly different. Inspection of the data revealed that a concentration in plasma of 105 ng/ml significantly separated responders and nonresponders (chi 2 = 3.93, df = 1, p < 0.05), but even at levels > or = 105 ng/ml, the response rate was still low relative to rates in prior studies of younger patients treated for a similar duration. The serious adverse reaction rate, 7 of 34, was similar to that previously observed in younger patients. This sample of "very old" elderly was not unusually "sensitive" to antidepressant drug treatment. In fact, the low rate of response observed at usually adequate levels in blood suggested "resistance" to treatment. The findings underscore the need for more effective drug treatments in the depressed elderly.

Differences in bioavailability between cocaine and cocaethylene and their implications for drug-reward studies

Cocaethylene, a psychoactive metabolite resulting from combined ethanol/cocaine consumption, is of interest because its psychostimulant properties may partially underlie combined cocaine/ethanol use, and because it has the potential for use as a probe of drug reward mechanisms due to its enhanced selectivity at monoamine uptake sites compared to cocaine. To determine the relative systemic bioavailabilities of cocaine and cocaethylene, sequential plasma samples were obtained from awake rats following drug administration. Following intravenous administration of 3 mumol/kg (molar equivalent of 1 mg/kg cocaine-HCl), both drugs achieved similar time courses and areas under the plasma concentration versus time curve. In contrast, intraperitoneal administration of 44 mumol/kg (molar equivalent of 15 mg/kg cocaine HCl) showed peak plasma levels, and the area under the plasma concentration vs time curve for cocaine to be approximately twice that for cocaethylene. Comparison of dose corrected areas under the curve of the two routes of administration for each drug indicated that relative systemic bioavailability of cocaethylene following intraperitoneal administration is only 58% that of cocaine. In addition, the elimination of both cocaine and cocaethylene was found to be slower following intraperitoneal administration compared to the intravenous route. The implications of these results are discussed with respect to the relative potency of these two compounds, as inferred from behavioral, drug reward, and lethality studies. Also, the differences noted will need to be taken into account when making mechanistic interpretations from comparative drug reward studies.

Platelet alpha-granule release in cocaine users

BACKGROUND

Cocaine use has been associated with arterial occlusion resulting from platelet-rich thrombi and with an accelerated, often atypical atherosclerotic lesion that could be ascribed to platelet activation and platelet alpha-granule release.

METHODS AND RESULTS

Using a flow cytometric method to quantitate the percent of circulating activated platelets in whole blood (those that express the alpha-granule membrane protein P-selectin), we found that 5 of 25 samples from 12 long-term cocaine users had a baseline level of circulating activated platelets > 3 SD (range, 19% to 60%) above the mean (4.4 +/- 3.7%, mean +/- 1 SD) for 85 nonusers (sample n = 130). This subset resulted in a significantly higher mean baseline level of circulating activated platelets (11.8 +/- 14.4%) for all cocaine users (P = .01). By contrast, cocaine and its metabolites, at concentrations documented as obtainable during in vivo cocaine use (10(-7) to 10(-5) mol/L), had no effect on in vitro platelet activation or aggregation, either directly or in concert with platelet agonists. However, in experiments in which cocaine users received blinded infusions of placebo or cocaine, the mean percent of circulating activated platelets rose significantly (P < .05) after infusion of either placebo (peak 77 +/- 31%) or cocaine (peak 65 +/- 28%), the latter at doses resulting in peak plasma cocaine levels averaging < 10(-6) mol/L.

CONCLUSIONS

Long-term cocaine use in some subjects is intermittently associated with high basal levels of circulating platelets that have undergone alpha-granule release. The inability of cocaine and its metabolites at concentrations of 10(-7) to 10(-5) mol/L to cause platelet P-selectin expression in vitro in this study, coupled with the acute increase in circulating activated platelets observed in vivo after either cocaine or placebo infusion, suggests that in vivo platelet alpha-granule release associated with cocaine use may occur through indirect rather than direct effects of the drug.

Solid-phase extraction combined with radioimmunoassay for measurement of zalcitabine (2',3'-dideoxycytidine) in plasma and serum

Of the antiviral agents that are currently in clinical use in the US for therapy for human immunodeficiency virus infections, zalcitabine (ddC) is the most potent and is effective at the lowest plasma concentrations. The two reported procedures for measuring these low concentrations involve a chromatographic technique coupled with mass spectrometry. We have developed a procedure combining solid-phase extraction with a strong cation-exchange resin and commercially available RIA reagents for the quantification of ddC in plasma or serum. The method demonstrates good linearity, specificity, and precision, with overall CVs of &lt; 10% from 2-20 micrograms/L and 17% at 0.8 microgram/L (the lower limit of quantitation). No significant cross-reactivity with nucleoside analogs other than ddC analogs was noted. The major advantages of this assay are its efficiency and relative simplicity, which should facilitate its performance in many laboratories.

Solid-phase extraction combined with radioimmunoassay for measurement of zalcitabine (2',3'-dideoxycytidine) in plasma and serum

Of the antiviral agents that are currently in clinical use in the US for therapy for human immunodeficiency virus infections, zalcitabine (ddC) is the most potent and is effective at the lowest plasma concentrations. The two reported procedures for measuring these low concentrations involve a chromatographic technique coupled with mass spectrometry. We have developed a procedure combining solid-phase extraction with a strong cation-exchange resin and commercially available RIA reagents for the quantification of ddC in plasma or serum. The method demonstrates good linearity, specificity, and precision, with overall CVs of < 10% from 2-20 micrograms/L and 17% at 0.8 microgram/L (the lower limit of quantitation). No significant cross-reactivity with nucleoside analogs other than ddC analogs was noted. The major advantages of this assay are its efficiency and relative simplicity, which should facilitate its performance in many laboratories.

Characteristics of desipramine-refractory depression

BACKGROUND

To determine the predictors of desipramine-refractory depression, the authors examined the outcome in patients with major depression who were admitted to a general hospital and treated with desipramine adjusted to an adequate blood level.

METHOD

Sixty-eight consecutive inpatients with DSM-III nonpsychotic unipolar major depression who had failed to respond to 1 week of hospitalization without drug treatment were studied. Outcome was assessed with the Yale Depression Inventory after a 4-week desipramine trial in which 24-hour plasma concentrations were used to rapidly achieve a therapeutic desipramine level.

RESULTS

Poor response to a therapeutic desipramine trial, which occurred in 15 of 50 patients, was significantly associated with definite personality disorder, prior treatment failure, near delusional status, age < or = 35 years, duration of depressive episode, recurrence of depression, dysthymia, and secondary depression. The first four items remained significantly correlated with poor response when the presence of the other items was accounted for using multiple regression. Drug response was not predicted by the diagnosis of melancholia (DSM-III and DSM-III-R) or initial severity of the depressive episode.

CONCLUSION

The four strongest correlates of outcome were highly predictive of drug response. In patients with two or more predictors, only 25% (4 of 16) responded, while in those with one or no predictors, 91% (31 of 34) responded.

Concurrent cocaine-ethanol ingestion in humans: pharmacology, physiology, behavior, and the role of cocaethylene

Simultaneous abuse of cocaine and ethanol is a common occurrence. Cocaethylene, the ethyl ester of benzoylecgonine, has been detected in the urine of patients reporting concurrent use of cocaine and ethanol, and high levels have been found in the blood of victims of fatal drug overdose. This placebo-controlled, double-blind study examined the pharmacokinetic, physiologic, and behavioral effects of dual cocaine and ethanol administration in humans (n = 6). Cocaethylene was found in the plasma only after administration of both cocaine and ethanol, and appeared to be eliminated more slowly than cocaine. Plasma cocaine concentrations were significantly higher during cocaine/ethanol administration. Euphorigenic effects were both enhanced and prolonged, and heart rate was significantly increased, following cocaine/ethanol administration as compared to administration of cocaine or ethanol alone.

Lithium in combination with perphenazine: effect on plasma monoamine metabolites

The addition of lithium to perphenazine altered the pattern of plasma homovanillic acid (HVA) during the course of treatment for acute psychosis. In the perphenazine-treated group plasma HVA declined significantly by days 7-9 of treatment, whereas in the perphenazine-plus-lithium group plasma HVA tended to increase. The pattern for plasma methoxyhydroxyphenethyl-glycol (MHPG) was not significantly different for the two groups. The addition of lithium to a neuroleptic may enhance the metabolism of dopamine.

Drug-responsive symptoms during early neuroleptic treatment

Identification of symptoms that are directly responsive to neuroleptic drugs at progressive phases of treatment is important for monitoring drug response and understanding the relationship between neurochemical mechanisms of drug action and disordered behavior. Using multiple regression analyses that controlled for pretreatment severity, we identified those symptoms that improved in direct relation to serum concentrations of perphenazine after 10 days of treatment. Improvement in two positive symptoms of psychosis--hallucinations and conceptual disorganization--appears to be related to perphenazine level and useful for assessment of early drug response.

Plasma free homovanillic acid (HVA) as a predictor of clinical response in acute psychosis

The relationship of plasma free homovanillic acid (HVA) and methoxyhydroxyphenylglycol (MHPG) to early clinical response was prospectively studied in a new series of acutely psychotic inpatients given a fixed dose of perphenazine elixir for 10 days. Elevated pretreatment plasma HVA but not MHPG was significantly associated with good response. Change in HVA was correlated with a favorable response and a significant decline in MHPG was found in responders. Results suggest that HVA can provide a useful clinical predictor of response, and that both dopamine metabolism and noradrenergic functioning, as measured by plasma HVA and MHPG, are reduced in effective neuroleptic treatment.

A preliminary, open study of the combination of fluoxetine and desipramine for rapid treatment of major depression

Prompted by a recent study suggesting that the combination of desipramine hydrochloride and fluoxetine down-regulates beta-adrenergic receptors more rapidly than either drug alone, we administered both desipramine and fluoxetine to 14 inpatients with major depression in an open, 4-week trial. Desipramine plasma levels drawn 24 hours after an initial standardized dose were used to rapidly adjust desipramine dosage and compensate for the interactive effects of fluoxetine on desipramine levels in the blood. Responses were retrospectively compared with those of 52 inpatients who were descriptively similar and previously treated in the same setting with desipramine alone. Response was significantly more rapid in the group that received both drugs. One week after treatment began, the mean change in Hamilton Depression Rating Scale scores was 42% in the group that received both drugs and 20% in the group that received desipramine alone (Mann-Whitney U test, P = .007). Two weeks after administration of the drugs, the mean change in scores of the group that received both drugs was 60%, while a 30% change was noted in the patients treated with desipramine alone (P = .001). Ten (71%) of the 14 patients in the group that received both drugs completely remitted (change in Hamilton Depression Rating Scale score of greater than 75%, and final score of less than 7) within 4 weeks, while few patients treated with desipramine alone met these criteria within 4 weeks. This preliminary study suggests that treatment with both desipramine and fluoxetine is a rapid and effective strategy for treatment of major depression, and supports recent hypotheses of noradrenergic-serotonergic synergism.

Value of the DST for predicting response of patients with major depression to hospitalization and desipramine

The authors examined the value of the dexamethasone suppression test (DST) for predicting response of patients with unipolar, nonpsychotic major depression to 1 week of hospitalization without antidepressant drugs and to a 4-week trial of desipramine at a fixed plasma level. The rates of response to hospitalization without drug treatment (defined as a score of 12 or less on the Hamilton Rating Scale for Depression) were not significantly different for the patients with a positive DST and those with a negative DST. This finding differs from those of prior studies of the DST and response to placebo. The responses of the DST-positive and DST-negative patients to desipramine also did not differ, a finding that replicates those in some prior reports.

The relationship between blood perphenazine levels, early resolution of psychotic symptoms, and side effects

Serum perphenazine concentrations and early resolution of psychosis were examined to determine if blood level monitoring could be used to maximize drug efficacy while limiting extrapyramidal side effects (EPS). Sixty-six acutely psychotic inpatients were given perphenazine 0.5 mg/kg/day for 10 days, and their response was rated blind to blood level. Although 36 of 66 patients showed resolution of psychosis, neither perphenazine nor N-dealkylated perphenazine levels were related to global response or to Brief Psychiatric Rating Scale (BPRS) totals. Improvement in two individual BPRS items (hallucinations and conceptual disorganization) was related to serum perphenazine levels and suggestive of a lower therapeutic threshold of 0.8 ng/mL. Perphenazine level was not correlated with EPS; but benztropine, given only if required for serious EPS, was more likely to be used when perphenazine levels were elevated. The data suggest that higher perphenazine levels were no more effective than moderate levels but that higher levels may be associated with increased EPS; the data also suggest that individual symptoms rather than global response were associated with a lower therapeutic perphenazine threshold.

Predictors of hospital outcome without antidepressants in major depression

Fifty-two consecutive inpatients with nonpsychotic unipolar major depression were assessed for response to 1 week of hospitalization without antidepressants. Each was rated at admission and at 1 week using the Hamilton Rating Scale for Depression (HRSD). Fifteen of 52 responded (HRSD score less than or equal to 12), 10 of whom improved by greater than or equal to 50% change in the HRSD score. Five variables were correlated with lack of hospital response: DSM-III melancholia, panic disorder, the DSM-III-R item "absence of personality disorder," admission severity, and age. Multiple regression showed an independent association between hospital outcome and the first three variables. Response to 1 week of hospitalization was found in 70% (14 of 20) of the patients who had none of the three identified predictors: melancholia, panic, and absence of personality disorder. In patients with one or more of these predictors, only 3% (1 of 32) responded.

Does melancholia predict response in major depression?

We examined the value of the melancholic distinction for predicting response to 1 week of hospitalization without antidepressant drugs and to a 4-week fixed plasma level desipramine (DMI) trial in patients with unipolar non-psychotic major depression. Both DSM-III and III-R criteria were tested. Response to hospitalization (HDRS less than or equal to 12) was much less common in DSM-III melancholic than in non-melancholic patients (1 of 19 vs. 18 of 37, chi 2 = 8.69, df = 1, P less than 0.001) and severity did not account for this association. DSM-III-R melancholia criteria were also associated with poor hospital response but slightly less predictive. Melancholic patients, however, diagnosed with either set of criteria, were not more likely to respond to drug treatment on any of the measures examined.

Plasma debrisoquin levels in the assessment of reduction of plasma homovanillic acid. The debrisoquin method

Plasma concentrations of unconjugated homovanillic acid (pHVA) reflect both central nervous system (CNS) and peripheral dopamine metabolism. Debrisoquin sulfate (DBQ) blocks peripheral, but not CNS, production of HVA from dopamine. Administration of DBQ has been used to decrease the proportion of peripherally produced HVA in pHVA measurements, making such measurements more reflective of CNS turnover of dopamine. We studied the relationships between DBQ dose, plasma DBQ (pDBQ) levels, and changes in pHVA in a group of 21 subjects (9 normal controls and 12 with Tourette's syndrome). DBQ dose was moderately correlated with pDBQ levels (r = 0.63, p = 0.002). Subjects (n = 8) with mean pDBQ levels above 60 ng/ml had a 48% to 66% decrease in mean pHVA levels; this may reflect nearly complete inhibition of peripheral HVA production. Subjects (n = 13) with mean pDBQ levels below 55 ng/ml had decreases in pHVA levels from 10% to 58%. No debrisoquin was detected in cerebrospinal fluid samples. These data suggest that pDBQ levels above 60 ng/ml are sufficient to assure substantial inhibition of peripheral HVA production and that monitoring pDBQ levels may be useful when employing this method for studying CNS metabolism.

Plasma catecholamine metabolites and treatment response at neuroleptic steady state

Using either haloperidol or perphenazine in a fixed-dose protocol, plasma free homovanillic acid (HVA) and methoxyhydroxyphenethylglycol (MHPG) were decreased in 37 nonorganic psychotic inpatients at neuroleptic steady state (7-9 days) in comparison with pretreatment values. The data indicate that the magnitude of the decline in HVA and MHPG was associated with treatment response and not with neuroleptic plasma levels.

Desipramine facilitation of initial cocaine abstinence

We conducted a double-blind, random assignment, six-week comparison of desipramine hydrochloride (n = 24), lithium carbonate (n = 24), and placebo (n = 24) treatments for cocaine dependence. Subjects were 72 outpatient cocaine abusers who met DSM-III-R dependence criteria for cocaine but not for other substance abuse. Subjects in each treatment group were similar in history of cocaine and other substance abuse, cocaine craving, sociodemographics, and other psychiatric comorbidity. Desipramine, compared with both other treatments, substantially decreased cocaine use. Lithium treatment outcome did not differ from that of placebo. Desipramine-treated subjects attained contiguous periods of abstinence substantially more frequently than subjects receiving lithium or placebo. Fifty-nine percent of the desipramine-treated subjects were abstinent for at least three to four consecutive weeks during the six-week study period, compared with 17% for placebo and 25% for lithium. Cocaine craving reductions were also substantially greater in the desipramine-treated subjects. Establishment of initial abstinence is the first stage in recovery from cocaine dependence. Our findings indicate that desipramine is an effective general treatment, for this first treatment stage, in actively cocaine-dependent outpatients.

Hydroxydesipramine in the elderly

Elevation of the hydroxy metabolites of the tricyclic antidepressants in the elderly has been demonstrated for nortriptyline and suggested for desipramine by a study reporting elevated hydroxydesipramine (OH-DMI) plasma levels in four older patients. In the current study, patients treated with desipramine (DMI) were studied to determine whether OH-DMI was elevated in two larger samples of depressed elderly patients and to determine the magnitude of the increase, if present. In Sample I, which consisted of 68 patients of whom 23 were over 60 years of age, a fixed target dose of DMI was employed. Sample II, in which 20 of the 56 patients were over 60, received a dose adjusted to attain a fixed target DMI blood level. OH-DMI levels were higher in patients over 60 than in younger patients but the differences were not significant in either sample individually. In the two samples combined, average OH-DMI levels were 11 ng/ml higher in patients over 60 and the difference was significant (t = 2.30, p = 0.02). If variations in dose are accounted for, OH-DMI concentrations are positively correlated with age in both samples. OH-DMI/DMI ratios were not higher in the patients over 60 in these samples, but OH-DMI/DMI ratios may be higher in patients on lower doses with low DMI levels, as is common in the treatment of elderly patients. If comparable dosage is administered, nonlinear increases in DMI levels result in lower OH-DMI/DMI ratios similar to those in younger patients. Although our findings of elevated hydroxy levels in the elderly are consistent with prior reports, the clinical importance of an 11 ng/ml difference, particularly in relation to total drug levels averaging 220 ng/ml, is questioned.

Antidepressant activity of 2-hydroxydesipramine

We describe the relationship of 2-hydroxydesipramine (OH-DMI) plasma levels and response in a prospective DMI study in which dosage was rapidly adjusted to achieve a relatively uniform DMI plasma level. In prior studies, OH-DMI plasma levels were not related to response, but in these fixed-dose protocols the effects of OH-DMI are easily obscured by the higher concentrations of the parent drug. We hypothesized that in this study a contribution of OH-DMI to response might become apparent because DMI levels were relatively constant. Inpatients with nonpsychotic, unipolar DSM-III major depression who remained depressed (Hamilton score greater than 18) after 1 week of hospitalization without medication received a 4-week DMI trial. Twenty-four-hour drug plasma levels were used to adjust dose to reach a target DMI steady-state plasma level. Twenty-seven patients completed the trial. On every measure of response, total drug levels (DMI + OH-DMI) were more strongly correlated with outcome than were DMI levels alone. With multiple regression, both DMI and OH-DMI levels were independently and significantly associated with response. These findings suggest that OH-DMI has antidepressant activity.

Correlates of early neuroleptic response using a uniform haloperidol dose

Twenty-one patients hospitalized for acute non-organic psychosis were treated with a fixed daily dose of haloperidol (0.2 mg/kg) for 10 days. Serum levels of haloperidol were significantly lower in the male patients at steady state as compared to females. Serum levels at 24 h and 48 h were highly correlated steady-state levels. Haloperidol levels at steady state were significantly correlated with global outcome at 10 days. Prolactin at haloperidol steady state was significantly related to global outcome at 10 days in the males. Pretreatment plasma free HVA but not MHPG was significantly related to outcome in males and females.

Nonlinear desipramine kinetics: prevalence and importance

Tricyclic antidepressant plasma levels have been used to guide dose adjustment in nonresponding patients, and recently 24-hour drug levels have been advocated for predicting therapeutic doses. Both methods of dose adjustment assume linear drug kinetics. Recent reports have suggested that desipramine kinetics are nonlinear, but the samples described were small, six subjects or fewer. In the current study, plasma desipramine concentrations were examined in 42 inpatients who were depressed who had achieved steady-state conditions with a low initial dose and subsequently with a higher dose. Desipramine concentrations increased significantly more than that predicted by the dose increase; however, only one third of the sample had substantial nonlinear changes (an increase in the concentration 50% greater than expected). In the remainder of the sample, disproportionate increases in plasma concentrations were not likely to be of clinical consequence.

Early neuroleptic response: clinical profiles and plasma catecholamine metabolites

Forty-seven psychotic inpatients who required neuroleptic treatment were studied with respect to some clinical and biochemical variables associated with early neuroleptic response. Compared to poor early responders, good responders were older at onset of illness and at index admission, less likely to have had a schizoid developmental history, and more likely to be married. There was a trend for good early responders to have received a diagnosis of affective psychosis or atypical psychotic disorder rather than schizophrenia or schizophreniform disorder. However, no behavioral symptom or sign differentiated good from poor early responders with the possible exception of pretreatment psychomotor retardation, which showed some association with poor response. Fasting plasma-free homovanillic acid was significantly higher in the good response group and 3-methoxy-4-hydroxyphenethylene glycol showed a similar trend.

Rapid desipramine dose adjustment using 24-hour levels

Prior work indicates that plasma tricyclic levels obtained 24 hours after a single dose correlate well with steady state levels achieved. Although this suggests that 24-hour levels could be used to predict the dose needed to reach a desired plasma level, this method has seldom been tested prospectively. In the current study we test this strategy and determine patients' tolerance of rapid dose adjustment. First, the relationship of 24-hour levels and steady state levels in a sample of 16 inpatients was determined using a fixed dose paradigm. In a second sample of 26 depressed inpatients, plasma desipramine levels obtained 24 hours after a single test dose were applied to the regression equation derived from the first sample in order to estimate the dose needed to achieve a steady state level of 140 ng/ml. Once determined, the full dose was then rapidly administered. Sixteen of the 18 (89%) patients who completed the dose adjustment study had steady state drug concentrations within a target range of 125 to 300 ng/ml. This distribution of levels differed significantly from that previously reported for a fixed dose sample in which only 19 of 83 (23%) patients had levels within this range. Dose adjustment using 24-hour levels was well tolerated and should help to attain a more rapid response to antidepressant treatment. This has important implications for reducing lengths of hospitalization for depressed inpatients. The technique should also prove useful in research where a uniform plasma level paradigm is desirable.

Neuroleptic dose and desipramine concentrations during combined treatment of unipolar delusional depression

The relationship of response to neuroleptic dose and desipramine plasma concentration was examined in 31 patients with unipolar delusional depression. The patients received either perphenazine or haloperidol for 1-2 weeks, after which desipramine, 2.5 mg/kg of body weight per day, was added. Neuroleptic dose varied among patients but was constant within individuals. Global response was rated retrospectively on the basis of outcome during the fourth week of combined drug treatment. Responders had higher plasma desipramine concentrations and had received higher neuroleptic doses than nonresponders had. The effective threshold level for desipramine was similar to that previously described for nonpsychotic melancholic patients, suggesting a similar mode of action for the drug in the two disorders.

Behavioral, biochemical, and blood pressure responses to alprazolam in healthy subjects: interactions with yohimbine

The effect of single doses of alprazolam (1.5 mg) and yohimbine (30 mg) and alprazolam and yohimbine given together on plasma free 3-methoxy-4-hydroxyphenylethyleneglycol (MHPG), cortisol, blood pressure, and subjective behavioral ratings was studied in eight healthy subjects. In comparison to placebo, alprazolam significantly reduced plasma MHPG and cortisol, systolic and diastolic blood pressure, and increased subjective ratings of drowsiness and mellow. Yohimbine and the alprazolam-yohimbine combination significantly increased plasma free MHPG. Concomitant yohimbine administration antagonized the effects of alprazolam on blood pressure and attenuated alprazolam-induced changes in cortisol and subjective ratings. The ability of alprazolam to decrease plasma MHPG and blood pressure contrasts with previously reported effects of diazepam. The implications of the findings of the present investigation to the postulated role of brain noradrenergic function in the etiology of panic anxiety and the therapeutic mechanism of action of antipanic treatment are discussed.

Desipramine plasma levels and response in elderly melancholic patients

The relationship of response and plasma desipramine concentrations was examined in elderly depressed patients to determine whether they were more sensitive to the antidepressant effects of the drug and whether they would respond at lower plasma concentrations than younger patients. Twenty-five inpatients over the age of 60, who met criteria for major depression with melancholia, were unipolar, were not delusional, were without active medical illness or definite brain disease, and were still depressed after 1 week of hospitalization off psychotropic drugs, were treated with desipramine (2.5 mg/kg) for 3 weeks. Of the 18 patients completing the drug trial, six responded and 12 did not. Desipramine levels of responders (median, 126 ng/ml) were higher than those of nonresponders (median, 81 ng/ml; Mann-Whitney test, p less than 0.05). The threshold for response was the same as the threshold (115 ng/ml) observed in 31 nondelusional melancholic patients under the age of 60 treated in a similar manner with desipramine. Among elderly patients with levels above 115 ng/ml, four of five responded, and below this level, two of 13 responded (Fisher's exact test, p less than 0.025). Five patients not responding to the initial 3-week trial responded when desipramine was increased and the plasma level rose above 115 ng/ml. The data indicate that elderly melancholic patients to not respond to lower desipramine plasma concentrations and that therapeutic levels are similar to those for younger melancholic patients. The doses of desipramine needed to reach these levels were also similar to those required in younger patients.

Alprazolam overdose: clinical findings and serum concentrations in two cases

Two patients who attempted suicide with alprazolam had markedly elevated serum concentrations but manifested only mild toxicity. Overdose with alprazolam appears much less likely to be life-threatening than overdose with the tricyclic antidepressants.

Increased anxiogenic effects of caffeine in panic disorders

The effects of oral administration of caffeine (10 mg/kg) on behavioral ratings, somatic symptoms, blood pressure and plasma levels of 3-methoxy-4-hydroxyphenethyleneglycol (MHPG) and cortisol were determined in 17 healthy subjects and 21 patients meeting DSM-III criteria for agoraphobia with panic attacks or panic disorder. Caffeine produced significantly greater increases in subject-rated anxiety, nervousness, fear, nausea, palpitations, restlessness, and tremors in the patients compared with healthy subjects. In the patients, but not the healthy subjects, these symptoms were significantly correlated with plasma caffeine levels. Seventy-one percent of the patients reported that the behavioral effects of caffeine were similar to those experienced during panic attacks. Caffeine did not alter plasma MHPG levels in either the healthy subjects or patients. Caffeine increased plasma cortisol levels equally in the patient and healthy groups. Because caffeine is an adenosine receptor antagonist, these results suggest that some panic disorder patients may have abnormalities in neuronal systems involving adenosine. Patients with anxiety disorders may benefit by avoiding caffeine-containing foods and beverages.

Ratio of serum prolactin to haloperidol and early clinical outcome in acute psychosis

The ratio of the increase in serum prolactin concentration to steady-state haloperidol concentration in acutely psychotic women correlated with early clinical improvement. Correction of prolactin response for neuroleptic concentration may provide a better clinical predictor than either measure alone.

Drug-responsive symptoms in melancholia

Depressive symptoms present in 43 patients with unipolar nondelusional melancholia were studied to determine which symptoms were the best measures of response to desipramine hydrochloride. An extended Hamilton Depression Scale was used to identify symptoms that were present frequently. We then determined which symptoms improved in direct relation to achievement of therapeutic plasma desipramine concentrations, using multiple regression analysis to account for pretreatment symptom severity. In ten symptoms, improvement was significantly associated with desipramine treatment. These ten symptoms seem to be the best measure of drug response during tricyclic antidepressant treatment in patients with nondelusional melancholia.

Plasma catecholamine metabolites and early response to haloperidol

Plasma homovanillic acid (HVA) and methoxyhydroxyphenyl glycol (MHPG) as well as serum haloperidol and prolactin were measured in patients admitted to a general hospital psychiatric service for treatment of acute psychosis. At 10 days, good responders compared to poor responders had higher mean plasma HVA values before and during the first week of treatment with 0.2-0.4 mg/kg haloperidol per day. MHPG values showed a similar pattern, although no significant differences were obtained between or within the two groups. Females predominated among good responders; neither DSM-III diagnoses nor steady state haloperidol levels differed significantly between the two groups. Significant correlations within some patients were obtained between prolactin and haloperidol (positive), prolactin and MHPG (negative), and HVA and MHPG (positive). Plasma catecholamine metabolites deserve further study as possible markers of early response to the treatment of acute psychosis with modest doses of neuroleptic drugs.

Effects of desipramine on clinical liver function tests

Results of liver function tests in 46 depressed patients changed little during treatment with desipramine and were uncorrelated with drug plasma levels. The findings suggest that tricyclic-associated hepatitis, rather than being dose dependent, is an uncommon, idiosyncratic phenomenon.

Subjective complaints during desipramine treatment. Relative importance of plasma drug concentrations and the severity of depression

Subjective complaints, including those traditionally considered tricyclic antidepressant side effects, were studied in 43 depressed inpatients during a three-week trial of desipramine hydrochloride. Multiple regression analysis was employed to examine the independent relationship of pretreatment symptoms, concurrent depression, and plasma drug concentrations to subjective complaints reported during treatment. As a group, subjective complaints were positively associated with pretreatment symptoms and the concurrent severity of depression, but not with plasma desipramine concentration. Of the 23 individual complaints studied, three increased during treatment and nine improved. Only two complaints, tremors and light-headedness, were significantly associated with plasma drug concentration. The data indicate that during initial treatment of severe depression with desipramine, subjective complaints are more likely to be symptoms of depression than side effects of the drug and that plasma desipramine determinations would not be useful for predicting or avoiding these complaints. The best management of most symptoms studied was adequate treatment of the depression.

Desipramine hydroxylation: variability and effect of antipsychotic drugs

Steady-state plasma concentrations of desipramine (DMI), unconjugated 2-OH DMI, and total 2-OH DMI were measured in 82 depressed inpatients, 35 of whom were concurrently receiving a phenothiazine or butyrophenone antipsychotic drug. In the patients not on an antipsychotic, the ratio of unconjugated metabolite to parent varied from 0.01 to 1.5, with a median of 0.48, and was inversely related to the parent drug level. Antipsychotic drug was associated with higher DMI levels and a lower proportion of OH-metabolite (median, 0.23). In both groups the unconjugated form accounted for only about 10% of the total metabolite. No relationship of age, sex, drinking history, or smoking to DMI or 2-OH DMI levels was found.