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Biomedical subjects

M A Frye

Publications and source records attributed to M A Frye.

At least 55 records · Page 3Linked to original sources

Gabapentin does not alter single-dose lithium pharmacokinetics.

Lithium (Li) and gabapentin are both exclusively eliminated by renal excretion. When used in combination, a competitive drug-drug interaction could possibly alter Li renal excretion with important clinical implications considering the rather narrow therapeutic index of Li. This study examined the single-dose pharmacokinetic profiles of Li in 13 patients receiving placebo and then steady-state gabapentin (mean daily dose: 3,646.15 mg). During both phases, a single 600-mg dose of Li was orally administered with serial Li levels obtained at time zero and at 0.25, 0.5, 1, 2, 3, 4, 8, 12, 24, 48, and 72 hours. The pharmacokinetic parameters assessed were the following: area under the concentration time curve (AUC) for Li, maximal concentration of Li (Li Cmax), and time to reach peak Li concentration (Li Tmax). For patients receiving gabapentin, the mean Li AUC at 72 hours was 9.91+/-3.54 mmol x hr/mL and did not differ significantly from the mean Li AUC of 10.19+/-2.89 mmol x hr/mL for patients receiving placebo. The mean Li Cmax was 0.69+/-0.13 mmol/L for gabapentin patients and did not differ from the mean Li Cmax of 0.72+/-0.15 mmol/L for placebo patients. The mean serum Li Tmax was 1.38+/-0.62 hours for gabapentin patients and did not differ significantly from the mean serum Li Tmax of 1.5+/-0.91 hours for placebo patients. These data indicate that gabapentin treatment at this high therapeutic dose does not cause clinically significant alterations in short-term Li pharmacokinetics in patients with normal renal function. These preliminary data warrant further controlled study in a larger, more heterogenous patient sample and a longer duration of assessment, but they do suggest that these two medications may be administered in combination for the management of bipolar disorder.

Acetates↗

A history of the use of anticonvulsants as mood stabilizers in the last two decades of the 20th century.

Anticonvulsants have moved into an important position as alternatives and adjuncts to lithium carbonate in the treatment of bipolar illness. Work with the nonhomologous model of kindled seizures helped in the choice of carbamazepine as a potential mood stabilizer and in the study of the mechanisms of action of the second generation anticonvulsants carbamazepine and valproate, as well as the putative third generation psychotropic anticonvulsants lamotrigine and gabapentin. Anticonvulsant neuropeptides such as TRH and nonconvulsant approaches with repeated transcranial magnetic stimulation (rTMS) also appear promising.

Anticonvulsants↗

Cost reduction with maintenance ECT in refractory bipolar disorder.

A case report of outpatient maintenance electroconvulsive therapy (ECT) is presented in a patient with bipolar disorder type I refractory to conventional medication treatment but responsive to ECT. A cost comparison is made showing substantial savings when outpatient maintenance ECT is used in lieu of inpatient hospitalization with ECT. A detailed life chart illustrating multiple medication trials that failed to stabilize the patient accompanies the financial summary. This case highlights the advantages of outpatient maintenance ECT for bipolar depression particularly with regard to safety, efficacy, and significant health care cost reduction.

Adult↗

Rapid cycling bipolar affective disorder: lack of relation to hypothyroidism.

Thyroid indices were measured after an extended period of medication-free evaluation averaging 6 weeks in 67 consecutively admitted patients with bipolar illness. Thyroid hormone levels -- thyroxine (T4), free T4 and triiodothyronine (T3) -- were not significantly different in the 31 rapid cyclers (> or = 4 affective episodes/year) than in 36 non-rapid cyclers. Analysis of covariance indicated a non-significant trend relation between higher T4 and a greater number of affective episodes in the year prior to admission and male gender when age was covaried. Several previous reports, primarily in medicated subjects, have suggested a link between rapid cycling patients and decreased peripheral thyroid indices (low hormone levels and elevated TSH), but now the majority of studies do not support such a relation. Among those in the literature, this study includes patients studied for the longest time off medications and further suggests that the commonly-cited relation between subclinical hypothyroidism and rapid cycling bipolar illness be reevaluated.

Adult↗

Comparative antidepressant effects of intravenous and intrathecal thyrotropin-releasing hormone: confounding effects of tolerance and implications for therapeutics.

A significant amount of preclinical and human data indicate that thyrotropin-releasing hormone (TRH) has antidepressant effects. Although early studies showing these effects using intravenous TRH were not consistently replicated, it has been suggested that this could be explained by its poor blood-brain barrier penetration. For this reason we compared the antidepressant effect of intrathecal and intravenous TRH administered in a double-blind design to 2 treatment-refractory patients with bipolar II disorder. Each experienced a robust antidepressant response by both routes; subsequent open trials of intravenous TRH also were effective until apparent tolerance developed. Intrathecal TRH was readministered and both subjects again experienced robust antidepressant responses. These preliminary data suggest a differential mechanism of tolerance to the two routes of administration and raise the possibility that a subgroup of patients may be responsive to the antidepressant effects of TRH independent of its route of administration.

Affect↗

Alternative approaches to refractory depression in bipolar illness.

Thus, there appears to be a large variety of approaches to refractory bipolar depression. In contrast to several decades ago, wherein augmentation of lithium with antidepressants and neuroleptics was essentially the only treatment mode available, a panoply of treatment options now exist. However, their relative efficacy in different illness subtypes and stages remains to be better delineated, as do their optimal sequencing and use in combination in individual patients. It is the opinion of these authors and many of our colleagues in the field that initial use of several mood stabilizer drugs in combination may have a preferable long-term outcome in some rapid cycling patients, compared with the immediate use of a unimodal antidepressant with an inadequate single mood stabilizer, although this remains to be systematically studied. The use of thyroid augmentation strategies would appear to have merit in relationship to not only the potential treatment of lithium-related hypothyroidism, but also in augmenting antimanic and antidepressant effects. As one moves toward some of the complex combination treatment strategies discussed in this chapter, one has to be particularly careful about drug interactions and their potential for toxicity as well as therapeutic effects. Perhaps a prevailing guideline would be to use these agents more carefully in combination therapy than in monotherapy, with slow upward titration of dose to individual patients' side effects thresholds, even in preference to targeting of conventional blood level windows. In this way, side effects can be avoided during the assessment of complex combination regimens. In addition, one should be aware of potential pharmacokinetic interactions. For example, with the addition of valproate to carbamazenine, one should reduce the dose of carbamazepine, as valproate will not only increase the free fraction of carbamazepine based on displacement of protein binding, but will lead to increased accumulation of carbamazepine-10,11-epoxide. This epoxide is not measured in conventional assays but could contribute to the side effects profile (Ketter and Post, 1994). Similarly, valproate will markedly increase blood levels of lamotrigine; the starting dose of this agent should be substantially lower than conventional dosage when these two drugs are used in combination. We suggest the utility of detailed mapping with a formal system-such as the Life Chart Methodology (LCM) (Leverich and Post, 1996)-of mood fluctuation vs. medications in order to optimize and rationalize complex combination therapy. In this way, not only can the nuances of partial response be better defined, but also basic decisions about the therapeutic index and relative likelihood of response can be more readily assessed. We have discussed the other merits of the life chart method as an important clinical treatment tool as well as a research tool in other venues, but reemphasize its potential great importance in the treatment of refractory cyclic bipolar patients, in whom an initial period of remission of depression may, in many instances, be as likely attributable to the natural course of illness as the current intervention being offered. As such, it behooves the clinician to have a systematic database for the more subtle issues of dose titration and sequential addition of medications in complex combination regimens. In the face of inefficiency to one combination strategy, how one moves to the next strategy remains a highly individualized, clinically-based algorithm. We suggest the potential utility of moving towards a new set of mood stabilizers and then repeating some of the unimodal antidepressant additions and augmentation trials in an attempt to overcome refractory depression. Refractory depression in bipolar patients should be viewed as a medical emergency in light of the high potential for suicide in the illness in general (Chen and Dilsaver, 1996) and in patients who have either sustained or episodic refracto

Bipolar Disorder↗

The place of anticonvulsant therapy in bipolar illness.

With the increasing recognition of lithium's inadequacy as an acute and prophylactic treatment for many patients and subtypes of bipolar illness, the search for alternative agents has centered around the mood stabilizing anticonvulsants carbamazepine and valproate. In many instances, these drugs are effective alone or in combination with lithium in those patients less responsive to lithium monotherapy, including those with greater numbers of prior episodes, rapid-cycling, dysphoric mania, co-morbid substance abuse or other associated medical problems, and patients without a family history of bipolar illness in first-degree relatives. Nineteen double-blind studies utilizing a variety of designs suggest that carbamazepine, or its keto-congener oxcarbazepine, is effective in acute mania; six controlled studies report evidence of the efficacy of valproate in the treatment of acute mania as well. Fourteen controlled or partially controlled studies of prophylaxis suggest carbamazepine is also effective in preventing both manic and depressive episodes. valproate prophylaxis data, although based entirely on uncontrolled studies, appear equally promising. Thus, both drugs are widely used and are now recognized as major therapeutic tools for lithium-nonresponsive bipolar illness. The high-potency anticonvulsant benzodiazepines, clonazepam and lorazepam, are used adjunctively with lithium or the anticonvulsant mood stabilizers as substitutes or alternatives for neuroleptics in the treatment of manic breakthroughs. Preliminary controlled clinical trials suggest that the calcium channel blockers may have antimanic or mood-stabilizing effects in a subgroup of patients. A new series of anticonvulsants has just been FDA-approved and warrant clinical trials to determine their efficacy in acute and long-term treatment of mania and depression. Systematic exploration of the optimal use of lithium and the mood-stabilizing anticonvulsants alone and in combination, as well as with adjunctive antidepressants, is now required so that more definitive treatment recommendations for different types and stages of bipolar illness can be more strongly evidence based.

Affect↗

Increased neural cell adhesion molecule in the CSF of patients with mood disorder.

Neural cell adhesion molecule (N-CAM) is involved in cell-cell interactions during synaptogenesis, morphogenesis, and plasticity of the nervous system. Disturbances in synaptic restructuring and neural plasticity may be related to the pathogenesis of several neuropsychiatric diseases, including mood disorders and schizophrenia. Disturbances in brain cellular function may alter concentrations of N-CAM in the CSF. Soluble human N-CAM proteins are detectable in the CSF but are minor constituents of serum. We have recently found an increase in N-CAM content in the CSF of patients with schizophrenia. Although the pathogenesis of both schizophrenia and mood disorders is unknown, ventriculomegaly, decreased temporal lobe volume, and subcortical structural abnormalities have been reported for both disorders. We have therefore measured N-CAM concentrations in the CSF of patients with mood disorder. There were significant increases in amounts of N-CAM immunoreactive proteins, primarily the 120-kDa band, in the CSF of psychiatric inpatients with bipolar mood disorder type I and recurrent unipolar major depression. There were no differences in bipolar mood disorder type II patients as compared with normals. There were no significant effects of medication treatment on N-CAM concentrations. It is possible that the 120-kDa N-CAM band present in the CSF is derived from CNS cells as a secreted soluble N-CAM isoform. Our results suggest the possibility of latent state-related disturbances in N-CAM cellular function, i.e., residue from a previous episode, or abnormal N-CAM turnover in the CNS of patients with mood disorder.

Adult↗

The relationship between antimanic agent for treatment of classic or dysphoric mania and length of hospital stay.

BACKGROUND: This retrospective study was conducted to evaluate the relationship between the mood-stabilizing agents lithium, carbamazepine, and divalproex sodium and time course of drug response as measured by length of hospital stay. METHOD: Seventy-eight patients were evaluated. Discharge date and length of hospitalization were obtained by review of the dictated discharge summary by investigators who were blind to medication status. Drug choice, including blood levels, was then identified as well as any adjunctive treatment. Statistical evaluation (SAS software) of time to improvement was conducted using nonparametric survival models. Possible confounding variables were assessed by parametric survival regression models and proportional hazards models. RESULTS: The individual survival curves of four major antimanic treatment groups revealed a significant difference by the second week of hospitalization in the divalproex sodium and the lithium/carbamazepine combination groups as compared with the lithium or carbamazepine groups (chi 2 = 13.83, df = 3, p = .003). The mean +/- SD length of stay was approximately 40% shorter for the divalproex sodium (10.2 +/- 2.0 days) and the lithium/carbamazepine combination (11.7 +/- 2.1 days) groups compared with the lithium alone (17.6 +/- 1.0 days) and the carbamazepine alone (18.1 +/- 3.0 days) groups. Regression analysis of possible confounding variables including adjunctive treatment (benzodiazepines and neuroleptics), severity of illness (number of years ill and previous hospitalizations), and discharge date revealed no statistically significant effect. CONCLUSION: Shortcomings of our study include those inherent in the design of a non-randomized, small naturalistic study and retrospective chart review. Our study does, however, suggest different drug response rates for the treatment of classic and dysphoric mania and warrants further controlled investigation.

Adult↗

Osteoporosis and calcification of the aorta.

In an age-stratified random sample of 200 Rochester, Minnesota women, the prevalence of aortic calcification rose with aging, as did the prevalence of vertebral fractures, while bone mass fell. The statistically significant positive association of aortic calcification with vertebral fractures and the negative associations with bone mass at six skeletal sites were mainly accounted for by age. After age-adjustment, the only association remaining was a negative one between calcified aortic plaques and bone mineral density (BMD) of the lumbar spine (P < 0.05). Aortic calcification was not associated with any measures of calcium metabolism, after adjusting for age, except for a slight negative association between linear aortic calcifications and 25(OH) vitamin D levels (P < 0.05). BMD values of the lumbar spine were somewhat greater than predicted for age in women with severe aortic calcification, but similar findings were seen at other skeletal sites and none of the differences was statistically significant. While overestimation of bone mass was generally minimal, severe aortic calcification may distort lumbar spine assessments in a minority of postmenopausal women.

Adult↗

Epidemiology of vertebral fractures in women.

Vertebral fracture prevalence was assessed in an age-stratified random sample of Rochester, Minnesota women aged 50 years and over. Vertebral fractures, including wedge and concavity as well as compression fractures, were common and increased with age. The estimated incidence of new vertebral fractures also rose with age, reaching 29.6 per 1,000 person-years in women aged greater than or equal to 85 years. The prevalence of one or more vertebral fractures also increased with declining bone mass, reaching 42% in women with spinal bone mineral density less than 0.6 g/cm2 by dual photon absorptiometry. Bone mass and age contributed independently to the risk of vertebral fracture, but "age" may reflect other manifestations of osteoporosis.

Adult↗

Elevated concentration of N-CAM VASE isoforms in schizophrenia.

Neural cell adhesion molecule (N-CAM) is a cell recognition molecule, four major isoforms (180, 140, 120, and 105-115 kDa) of which are present in brain. N-CAM has several roles in cellular organization and CNS development. Previously we have found an elevation in CSF N-CAM 120 kDa in the CSF of patients with schizophrenia, bipolar disorder, and depression. We now report an increase in the variable alternative spliced exon (VASE), a 10 amino acid sequence inserted into the fourth N-CAM domain, in the CSF of patients with schizophrenia, but not in bipolar disorder or depression. VASE-immunoreactive (VASE-ir) bands were measured in CSF from patients with schizophrenia (n = 14), bipolar disorder I (n = 7), bipolar disorder II (n = 9), unipolar depression (n = 17) and matched controls (n = 37) by Western immunoblotting. Three VASE-ir bands were distinguished in lumbar CSF corresponding to heavy (165 kDa), medium (155 kDa) and low (140 kDa) MW. A logarithmic transformation was applied to the VASE protein units and analyzed with a MANOVA. There was a 51% and 45% increase in VASE heavy (p = 0.0008) and medium (p = 0.04) MW protein, respectively, in patients with schizophrenia as compared with normal controls. Current neuroleptic treatment in patients with schizophrenia had no effect on CSF VASE concentrations. VASE concentration correlated significantly with behavioral ratings in patients with schizophrenia but not affective disorders. Thus, VASE immunoreactivity is increased in schizophrenia but not in affective disorders. These results provide further evidence of an abnormality of N-CAM protein in chronic schizophrenia and suggest differences between schizophrenia and affective disorders in regulation of N-CAM.

Alternative Splicing↗