Studies on dexamethasone metabolism in man: effect of diphenylhydantoin

Role of Dexamethasone and Methylprednisolone Corticosteroids in Coronavirus Disease 2019 Hospitalized Patients: A Review

The WHO announced coronavirus disease 2019 (COVID-19) as a pandemic disease globally on March 11, 2020, after it emerged in China. The emergence of COVID-19 has lasted over a year, and despite promising vaccine reports that have been produced, we still have a long way to go until such remedies are accessible to everyone. The immunomodulatory strategy has been kept at the top priority for the research agenda for COVID-19. Corticosteroids have been used to modulate the immune response in a wide range of diseases for the last 70 years. These drugs have been shown to avoid and reduce inflammation in tissues and the bloodstream through non-genomic and genomic effects. Now, the use of corticosteroids increased the chance of survival and relief by combating the viral strong inflammatory impacts and has moved to the forefront in the management of patients seeking supplemental oxygen. The goal of this review is to illuminate dexamethasone and methylprednisolone, i.e., in terms of their chemical and physical properties, role in COVID-19 patients suffering from pneumonia, the proposed mode of action in COVID-19, pharmacokinetics, pharmacodynamics, clinical outcomes in immunocompromised populations with COVID-19, interaction with other drugs, and contradiction to explore the trends and perspectives for future research. Literature was searched from scientific databases such as Science Direct, Wiley, Springer, PubMed, and books for the preparation of this review. The RECOVERY trial, a massive, multidisciplinary, randomized, and open-label trial, is mainly accountable for recommendations over the usage of corticosteroids in COVID-19 patients. The corticosteroids such as dexamethasone and methylprednisolone in the form of medication have anti-inflammatory, analgesic, and anti-allergic characteristics, including the ability to inhibit the immune system. These drugs are also recommended for treating symptoms of multiple ailments such as rheumatic and autoimmune diseases, leukemia, multiple myeloma, and Hodgkin’s and non-Hodgkin’s lymphoma along with other drugs. Toxicology studies proved them safe usually at low dosage via oral or other routes.

Simultaneous assay of cortisol and dexamethasone improved diagnostic accuracy of the dexamethasone suppression test

OBJECTIVES

The overnight dexamethasone (DXM) suppression test (DST) has high sensitivity, but moderate specificity, for diagnosing hypercortisolism. We have evaluated if simultaneous measurement of S-DXM may correct for variable DXM bioavailability and increase the diagnostic performance of DST, and if saliva (sa) is a feasible adjunct or alternative to serum.

DESIGN AND METHODS

Prospective study of DST was carried out in patients with suspected Cushing's syndrome (CS) (n = 49), incidentaloma (n = 152) and healthy controls (n = 101). Cortisol, cortisone and DXM were assayed by liquid chromatography-tandem mass spectrometry (LC-MS/MS).

RESULTS

Three hundred and two subjects underwent DST; S-cortisol was ≥50 nmol/L in 83 patients, of whom 11 had CS and 27 had autonomous cortisol secretion. The lower 2.5 percentile of S-DXM in subjects with negative DST (n = 208) was 3.3 nmol/L, which was selected as the DXM cut-off level. Nine patients had the combination of low S-DXM and positive DST. Of these, three had been misdiagnosed as having autonomous cortisol secretion. DST results were highly reproducible and confirmed in a replication cohort (n = 58). Patients with overt CS had significantly elevated post-DST sa-cortisol and sa-cortisone levels compared with controls; 23 of 25 with autonomous cortisol secretion had elevated sa-cortisone and 14 had elevated sa-cortisol.

CONCLUSIONS

Simultaneous measurement of serum DXM and cortisol reduced false-positive DSTs by 20% and improved the specificity. S-DXM >3.3 nmol/L is sufficient for the suppression of cortisol <50 nmol/L. Measurement of glucocorticoids in saliva is a non-invasive and easy procedure and post-DST sa-cortisone was found particularly useful in the diagnosis of CS.

Efficacy and tolerability of lacosamide for secondary epileptic seizures in patients with brain tumor: A multicenter, observational retrospective study

The present observational, multicenter, retrospective study investigated the efficacy and tolerability of lacosamide in controlling secondary epileptic seizures in patients with brain tumors in Spain. Data from the medical records of patients ≥18 years of age with brain tumors, who had received at least one dose of lacosamide for seizure management between July 2013 and November 2013, were collected. The primary and secondary objectives of the present study were to assess the effectiveness and tolerability of lacosamide. Data from 39 patients (mean age, 54.1 years; 66.7% male) were collected, where the two main reasons for initiation of lacosamide treatment were the lack of efficacy of other antiepileptic drugs (in 76.9% of patients) and the presence of adverse events (12.8%) associated with other antiepileptic drugs. At the initiation of treatment, patients received a mean lacosamide dose of 138.5±68.3 mg/day. At 6 months, lacosamide had significantly reduced the mean number of seizures from 26.4 (standard deviation [SD], 50.4) seizures for the 6 months prior to lacosamide initiation to a mean of 9.4 (SD, 22.8) seizures during the 6 months subsequent to lacosamide initiation; P<0.001. Lacosamide was generally well tolerated; of the 25 patients who had complete safety data available at a 6-month follow-up, 3 patients (12%) reported an adverse event, including dizziness, asthenia, instability and irritability. The present retrospective analysis suggested that lacosamide is an effective and well-tolerated treatment in patients experiencing seizures due to brain tumors. Additional prospective studies with a larger patient population and randomized trial design are warranted.

The palliation of cerebral tumours with high-dose dexamethasone: a review

The historical use of corticosteroids for cerebral oedema due to malignancy is reviewed. The mechanisms for the formation and treatment of cerebral oedema are discussed and advice is given as to the clinical use of dexamethasone, including mention of adverse effects and drug interactions.

Treatment of hypopituitarism in patients receiving antiepileptic drugs

Evidence suggests that there may be drug interactions between antiepileptic drugs and hormonal therapies, which can present a challenge to endocrinologists dealing with patients who have both hypopituitarism and neurological diseases. Data are scarce for this subgroup of patients; however, data for the interaction of antiepileptic drugs with the pituitary axis have shown that chronic use of many antiepileptic drugs, such as carbamazepine, oxcarbazepine, and topiramate, enhances hepatic cytochrome P450 3A4 (CYP3A4) activity, and can decrease serum concentrations of sex hormones. Other antiepileptic drugs increase sex hormone-binding globulin, which reduces the bioactivity of testosterone and estradiol. Additionally, the combined oestrogen-progestagen contraceptive pill might decrease lamotrigine concentrations, which could worsen seizure control. Moreover, sex hormones and their metabolites can directly act on neuronal excitability, acting as neurosteroids. Because carbamazepine and oxcarbazepine can enhance the sensitivity of renal tubules, a reduction in desmopressin dose might be necessary in patients with central diabetes insipidus. Although the effects of antiepileptic drugs in central hypothyroidism have not yet been studied, substantial evidence indicates that several antiepileptic drugs can increase thyroid hormone metabolism. However, although it is reasonable to expect a need for a thyroxine dose increase with some antiepileptic drugs, the effect of excessive thyroxine in lowering seizure threshold should also be considered. There are no reports of significant interactions between antiepileptic drugs and the efficacy of human growth hormone therapy, and few data are available for the effects of second-generation antiepileptic drugs on hypopituitarism treatment.

Corticosteroids in brain cancer patients: benefits and pitfalls

Glucocorticoids have been used for decades in the treatment of brain tumor patients and belong to the most powerful class of agents in reducing tumor-associated edema and minimizing side effects and the risk of encephalopathy in patients undergoing radiation therapy. Unfortunately, corticosteroids are associated with numerous and well-characterized adverse effects, constituting a major challenge in patients requiring long-term application of corticosteroids. Novel antiangiogenic agents, such as bevacizumab (Avastin®), which have been increasingly used in cancer patients, are associated with significant steroid-sparing effects, allowing neuro-oncologists to reduce the overall use of corticosteroids in patients with progressive malignant brain tumors. Recent experimental studies have revealed novel insights into the mechanisms and effects of corticosteroids in cancer patients, including modulation of tumor biology, angiogenesis and steroid-associated neurotoxicity. This article summarizes current concepts of using corticosteroids in brain cancer patients and highlights potential pitfalls in their effects on both tumor and neural progenitor cells.

[Primary prophylaxis of early seizures after surgery of cerebral supratentorial tumors: Group for the Study of Functional-Sterotactic Neurosurgery of The Spain Society of Neurosurgery recommendations]

Our review of the literature is basically focused on the primary prophylaxis of early seizures after surgery of cerebral supratentorial tumors, with the aim of suggesting several recommendations in medical antiepileptic treatment to avoid this kind of seizures which occur immediately after surgery. In conclusion, it is recommended to provide criteria for prophylaxis of early seizures after surgery of cerebral supratentorial tumors. It́s recommended a one week treatment with antiepileptic drugs in patients who didńt have seizures jet, starting immediately after the surgical treatment. If seizures appear during progress of the disease, a large period treatment will be needed. Preferred antiepileptic treatment is intravenous and with a low interactions profile. Levetiracetam, followed by valproic acid seem to be most appropriated drugs due to their properties and protective effects, particularly for our patients requirements. These recommendations are considered a general proposal to effective clinical management of early seizures after surgery, not taking into account the single circumstances of our patients. Always, clinical features of the patients could modify even significantly these guides in the benefit of each patient.

Seizures and brain tumors

Seizures commonly occur in people with brain tumors. They may be the presenting symptom of a brain tumor, or develop some time after tumor diagnosis. The risk of seizures is greatest when the tumors have a central location, slow growth rate, and when multiple lesions are present. Interactions between anti-epileptic drugs (AEDs), chemotherapeutic agents, and corticosteroids increase the complexity and challenge in managing seizures, and drugs that do not interfere with the cytochrome P-450 enzyme complex and have low protein binding may be preferable. The comparative efficacy and side effects of the various AEDs are not established in brain tumors, so drug choice relies on both the theoretical advantages of pharmacokinetic properties and clinical judgment. Prophylactic anticonvulsant treatment is not advisable in brain tumor patients who have not experienced seizures.

Pharmacokinetic interactions with rifampicin : clinical relevance

The antituberculosis drug rifampicin (rifampin) induces a number of drug-metabolising enzymes, having the greatest effects on the expression of cytochrome P450 (CYP) 3A4 in the liver and in the small intestine. In addition, rifampicin induces some drug transporter proteins, such as intestinal and hepatic P-glycoprotein. Full induction of drug-metabolising enzymes is reached in about 1 week after starting rifampicin treatment and the induction dissipates in roughly 2 weeks after discontinuing rifampicin. Rifampicin has its greatest effects on the pharmacokinetics of orally administered drugs that are metabolised by CYP3A4 and/or are transported by P-glycoprotein. Thus, for example, oral midazolam, triazolam, simvastatin, verapamil and most dihydropyridine calcium channel antagonists are ineffective during rifampicin treatment. The plasma concentrations of several anti-infectives, such as the antimycotics itraconazole and ketoconazole and the HIV protease inhibitors indinavir, nelfinavir and saquinavir, are also greatly reduced by rifampicin. The use of rifampicin with these HIV protease inhibitors is contraindicated to avoid treatment failures. Rifampicin can cause acute transplant rejection in patients treated with immunosuppressive drugs, such as cyclosporin. In addition, rifampicin reduces the plasma concentrations of methadone, leading to symptoms of opioid withdrawal in most patients. Rifampicin also induces CYP2C-mediated metabolism and thus reduces the plasma concentrations of, for example, the CYP2C9 substrate (S)-warfarin and the sulfonylurea antidiabetic drugs. In addition, rifampicin can reduce the plasma concentrations of drugs that are not metabolised (e.g. digoxin) by inducing drug transporters such as P-glycoprotein. Thus, the effects of rifampicin on drug metabolism and transport are broad and of established clinical significance. Potential drug interactions should be considered whenever beginning or discontinuing rifampicin treatment. It is particularly important to remember that the concentrations of many of the other drugs used by the patient will increase when rifampicin is discontinued as the induction starts to wear off.

Prophylactic anticonvulsants in patients with brain tumour

OBJECTIVE

We conducted a clinical trial to determine if prophylactic anticonvulsants in brain tumour patients (without prior seizures) reduced seizure frequency. We stopped accrual at 100 patients on the basis of the interim analysis.

METHODS

One hundred newly diagnosed brain tumour patients received anticonvulsants (AC Group) or not (No AC Group) in this prospective randomized unblinded study. Sixty patients had metastatic, and 40 had primary brain tumours. Forty-six (46%) patients were randomized to the AC Group and 54 (54%) to the No AC Group. Median follow-up was 5.44 months (range 0.13-30.1 months).

RESULTS

Seizures occurred in 26 (26%) patients, eleven in the AC Group and 15 in the No AC Group. Seizure-free survivals were not different; at three months 87% of the AC Group and 90% of the No AC Group were seizure-free (log rank test, p = 0.98). Seventy patients died (unrelated to seizures) and survival rates were equivalent in both groups (median survival = 6.8 months versus 5.6 months, respectively; log rank test, p = 0.50). We then terminated accrual at 100 patients because seizure and survival rates were much lower than expected; we would need > or = 900 patients to have a suitably powered study.

CONCLUSIONS

These data should be used by individuals contemplating a clinical trial to determine if prophylactic anticonvulsants are effective in subsets of brain tumour patients (e.g. only anaplastic astrocytomas). When taken together with the results of a similar randomized trial, prophylactic anticonvulsants are unlikely to be effective or useful in brain tumour patients who have not had a seizure.

Hypercortisolemia decreases dexamethasone half-life in rabbit

The pharmacokinetics of dexamethasone have been found to be related to endogenous hypothalamic-pituitary-adrenal (HPA) axis activity. Lower plasma dexamethasone levels in psychiatric patients (especially depressed) who are dexamethasone suppression test (DST) nonsuppressors have previously been reported. Since DST nonsuppression is one measure of HPA axis hyperactivity and is usually associated with relatively increased plasma cortisol levels and lower post dose plasma dexamethasone levels, we hypothesized that hypercortisolemia can induce a more rapid disappearance of dexamethasone from plasma. We therefore studied the kinetics of dexamethasone in rabbits before and after a period of sustained hypercortisolemia produced by administration of IM hydrocortisone acetate, a slowly absorbed salt of cortisol. Mean dexamethasone half-life decreased significantly from baseline of 1.92 h on day zero in seven rabbits to 1.17 h on experimental day 17 of induced hypercortisolemia (P < 0.001), while there was no significant change in saline treated controls (n = 3). Dexamethasone half-life had returned to the baseline levels when retested 88 days later on experimental day 105. The results indicate that pronounced hypercortisolemia decreases dexamethasone half-life in rabbits, and support the concept that increased circulating cortisol levels induce hepatic enzymes that metabolize dexamethasone. Thus, the lower postdexamethasone plasma dexamethasone levels and decreased dexamethasone half-life in DST nonsuppressors may in part reflect the effect of prior or coincident hypercortisolemia.

Inositol treatment has no effect on the dexamethasone suppression test

The dexamethasone suppression test (DST) is a widely studied state marker for endogenous depression. Several drugs cause false positives or negatives in this test. Since inositol is a new treatment for depression it is important to determine if it causes artifacts in the DST. Five patients with major depression diagnosed according to DSM-IV underwent a dexamethasone suppression test before and after one and two weeks of 12 grams daily inositol treatment. Three normal subjects underwent the same procedure before and after one week of inositol treatment. Four depressed patients and all three normal subjects demonstrated pretreatment dexamethasone suppression of plasma cortisol. One or two weeks of inositol treatment had no effect on post-dexamethasone cortisol plasma levels in patients or subjects. One depressed patient was a non-suppressor before treatment and continued to show elevated post dexamethasone cortisol levels after one week of inositol treatment. However, after two weeks on inositol, when substantial clinical improvement was noted, he converted to a normal DST. Chronic inositol treatment does not seem to induce false positive DST results.

Treatment of lupus with corticosteroids

Through direct signals to the nucleus mediated by the glucocorticoid receptor, exogenous glucocorticoids impact a broad array of cellular functions. DNA binding of the glucocorticoid receptor, depending upon the specific promoter to which the receptor binds, affects gene expression by recruiting transcription factors to the promoter or by interfering with the function of co-factors required for gene transcription. Steroid effects on the adhesion functions and release of products by phagocytic cells are prompt, occurring within hours of administration. Administration of corticosteroids results in rapid depletion of circulating T-cells due to a combination of effects including enhanced circulatory emigration, induction of apoptosis, inhibition of T-cell growth factors, and impaired release of cells from lymphoid tissues. Corticosteroid effects on B-cell function and immunoglobulin production are more delayed. The broad, generally suppressive effects of corticosteroids on the immune response render them useful for the management of most organ system manifestations of lupus. Corticosteroid toxicity in lupus is notable for greater susceptibility to infections, osteoporosis, osteonecrosis and accelerated atherogenesis. Although use of corticosteroids for patients with severe disease manifestations is associated with higher numbers of deaths from infections, overall survival appears to be improved.

Dexamethasone metabolism in dexamethasone suppression test suppressors and nonsuppressors

BACKGROUND

Variable dexamethasone kinetics is a possible confound in the dexamethasone suppression test. Modifications to include dexamethasone plasma levels and specific dexamethasone "windows" have been proposed. Our study aims to validate our proposed dexamethasone windows in an independent sample of 121 subjects.

METHODS

We performed dexamethasone suppression tests in 162 subjects with mixed psychiatric diagnoses. Dexamethasone levels and beta-phase half-life of dexamethasone were computed for suppressors and nonsuppressors.

RESULTS

Dexamethasone levels were lower in nonsuppressors than in suppressors. Dexamethasone levels correlated inversely with cortisol levels in the total sample, but were nonsignificant or weakly associated in those samples restricted to the windows. The beta-phase half-life of dexamethasone was shorter in nonsuppressors. The dexamethasone windows were validated at 3:00 PM and 10:00 PM. We propose 4.0 ng/mL as a revised upper limit of the 8:00 AM dexamethasone window.

CONCLUSIONS

The plasma dexamethasone level is confirmed as a confound in the dexamethasone suppression test through more rapid dexamethasone clearance in nonsuppressors. Application of dexamethasone windows will reduce this source of test variance.

Effect of phenobarbitone on the low-dose dexamethasone suppression test and the urinary corticoid: creatinine ratio in dogs

OBJECTIVES

To investigate potential effects of phenobarbitone on the low-dose dexamethasone suppression (LDDS) test and urinary corticoid to creatinine ratio in dogs in a controlled prospective study and in a clinical setting.

ANIMALS

Ten crossbreed experimental dogs and 10 client-owned dogs of mixed breeds treated chronically with phenobarbitone to control seizures.

PROCEDURES

Experimental dogs were allocated to treatment (6 mg/kg oral phenobarbitone, n = 6) and control (n = 4) groups. LDDS tests (dexamethasone 0.01 mg/kg intravenously, cortisol concentration determined at 0, 2, 4, 6 and 8 h) were conducted repeatedly over a 3-month period. Urinary corticoid to creatinine ratios were measured before LDDS tests. A single LDDS test was performed on 10 epileptic dogs.

RESULTS

LDDS and urinary corticoid to creatinine ratios in dogs were not affected by treatment with phenobarbitone.

CONCLUSIONS

Phenobarbitone does not interfere with LDDS testing regardless of dosage or treatment time. Urinary corticoid to creatinine ratios are also unaffected.

Plasma dexamethasone concentration and cortisol response during manic episodes

BACKGROUND

Despite the widespread study of the dexamethasone suppression test (DST) in patients diagnosed with major depression, it has been less well studied during manic and mixed states of bipolar disorder.

METHODS

Cortisol response to the administration of 1 mg of dexamethasone was studied in 44 patients diagnosed bipolar disorder, manic (n = 37) or mixed (n = 7). Dexamethasone levels and cortisol responses were compared between these groups. Four patients initially meeting criteria for bipolar disorder, mixed, and 7 patients initially meeting criteria for bipolar disorder, manic, all of whom were characterized as DST nonsuppressors, were retested after remission.

RESULTS

Dexamethasone levels were lower and cortisol levels higher in those patients diagnosed bipolar disorder, mixed. An inverse correlation was found between log-transformed dexamethasone levels and log-transformed cortisol levels at 3 PM (r = -.619, p < or = .001) and 10 PM (r = -.501, p < or = .001). In those subjects retested after remission, dexamethasone levels were higher and cortisol levels lower than during the manic and mixed states.

CONCLUSIONS

Disturbances in the hypothalamic-pituitary-adrenal axis are observed frequently during mixed states of bipolar disorder, but are also not uncommon in purely manic episodes. These changes appear to be state dependent and revert with treatment.

Pig hepatocytes as an in vitro model to study the regulation of human CYP3A4: prediction of drug-drug interactions with 17 alpha-ethynylestradiol

The objective of this study was to provide evidence of the validity of pig hepatocytes as a model to study the regulation of human CYP3A4 with special emphasis on drug-drug interactions. Thirteen different drugs were incubated with primary monolayer cultures of pig hepatocytes (n = 4). The study included both drugs reported to cause drug interactions in the clinic with 17 alpha-ethynylestradiol (EE2), other drugs metabolized by CYP3A4, and drugs not reported to cause any problems. Effect of the drug exposure to pig hepatocytes was determined by immunodetection using a monoclonal human CYP3A4 antibody and measurement of 6 beta-hydroxylation of testosterone and 2-hydroxylation of 17 alpha-ethynylestradiol (EE2), both reactions known to be catalyzed by CYP3A4 in humans. Data were compared to data from human hepatocytes and to reported observations of drug-drug interactions in the clinic. The drugs known to be inducers of CYP3A4 in humans significantly increased a CYP isoform in pigs catalyzing 6 beta-hydroxylation of testosterone and 2-hydroxylation of EE2, whereas drugs not reported to have clinical interactions with EE2 had no or only marginal effect. Induction by the drugs known to be inducers of CYP3A4 increased with drug exposure time and the CYP3A4 activity, represented by testosterone 6 beta-hydroxylation, was highest at 72 h for the investigated induction periods (24, 48 and 72 h), except for dexamethasone where the effect peaked after 24 h. Induction of the 2-hydroxylation of EE2 correlated well with the increase in 6 beta-hydroxylation of testosterone (except for sulphinpyranzone) and the increase in the protein level of CYP3A detected by a monoclonal human CYP3A4 antibody, thus confirming the 2-hydroxylation of EE2 in pigs as being biotransformed by a CYP isoform presumably belonging to the CYP3A subfamily as in humans. In conclusion, these results indicate that pig hepatocytes may be a valuable model to mimic the regulation of human CYP3A4.

Are blunted dexamethasone-induced growth hormone responses unique to depression?

In health, acute administration of glucocorticoids, such as dexamethasone (DEX), leads to growth hormone (GH) secretion. Depression is characterized by blunted DEX/GH responses. In order to determine the specificity of this test for depression we administered 4 mg of oral DEX, to patients with a DSM-III-R diagnosis of depression, schizophrenia, mania and alcohol dependency syndrome. Samples for GH estimation were taken at -15 min, 0 min, +60 min, +180 min, +240 min and +300 min. GH responses were attenuated to a similar degree in depression and mania. Less marked attenuation was seen in schizophrenia while those with alcohol dependency syndrome had GH responses indistinguishable from normal volunteers. Overall, we conclude that subnormal DEX/GH secretion is not specific to depression.

The hypothalamic-pituitary-adrenal axis in obesity

The hypothalamic-pituitary-adrenal (HPA) axis normally maintains the concentration of cortisol within a narrow range with a diurnal variation characterized by higher cortisol concentrations in the morning and reduced levels in the evening. Excessive or deficient secretion of cortisol is associated with pathologic changes. Obesity has been linked with age, sex and racial alterations in the functioning of the HPA axis which are reviewed. The possible relationship of altered HPA axis activity with the long-term complications of obesity are considered.

Management of brain metastases

Brain metastases usually develop in patients with disseminated systemic disease. Effective palliation is available for the vast majority of patients with brain metastases, but many will die within 6 months, usually from progressive systemic tumor. However, in a substantial proportion of patients, a vigorous therapeutic approach using surgery, radiotherapy, and possibly chemotherapy leads to years of productive life. Recurrent brain metastases can often be retreated using newer techniques of brachytherapy and stereotactic radiosurgery as well as conventional treatments. Brain metastases do not necessarily mean imminent death for every patient, and physicians can now offer patients a growing range of therapeutic options. Furthermore, attention to symptomatic therapies can improve the quality of life for all patients, even those whose survival will be relatively short.

Preliminary studies of 6 beta-hydroxydexamethasone and its importance in the DST

The role of the metabolites of dexamethasone (DEX) in the dexamethasone suppression test (DST) has never been fully elucidated. We report here our preliminary studies of 6 beta-hydroxydexamethasone (6 OH-Dex), a known metabolite of DEX, on the hypothalamic-pituitary-adrenal (HPA) axis of the rat; its activity in the most commonly used radioimmunoassay for plasma DEX; and its plasma concentrations in a normal human subject during the standard 1.0 mg DST. Six OH-Dex administered subcutaneously to rats at a dose of 1 mg/kg was able to completely suppress corticosterone production for at least 3 hr. In the IgG Corp. radioimmunoassay for plasma DEX, 6 OH-Dex was moderately cross-reactive yielding a 50% cross-reactivity of 10%. Gas chromatographic coupled mass spectroscopic analysis of human plasma samples, obtained 12 to 20 hr after the oral ingestion of 1.0 mg DEX, demonstrated similar plasma concentrations for both the parent compound and the 6-hydroxyl metabolite. The relevance of these findings, particularly to pharmacokinetic studies of the DST, is discussed.

Effects of antiepileptic drugs on hormones

A hormone is an intrinsic substance carried via the blood to a target organ which is then functionally stimulated. Similar to extrinsically administered medications, the metabolism and function of the hormones may be altered by antiepileptic drugs (AEDs). The proposed mechanisms are (a) enhanced metabolism (natural steroids, synthetic steroids, e.g., decadron and birth control pills, thyroxine, and vitamin D3), (b) altered protein bonding (thyroxine, sex hormones), (c) impaired release into the systemic circulation (calcitonin, insulin, vitamin K clotting factors) and (d) altered end-organ effect. The AEDs most likely to interact with hormones are barbiturates, carbamazepine, and phenytoin.

A possible defect in the inter-conversion between cortisone and cortisol in prepubertal patients with congenital adrenal hyperplasia receiving cortisone acetate therapy

Oral administration of cortisone acetate is widely used to treat prepubertal patients with congenital adrenal hyperplasia (CAH). However, efficient 'first pass' hepatic conversion of the biologically inactive cortisone (E) to cortisol (F) by the 11-reductase component of the 11 beta-hydroxysteroid dehydrogenase (11 beta-HSD) system is required for suppression of the hypothalamic-pituitary-adrenal (HPA) axis. 11-beta-HSD activity can be assessed by measurement of urinary tetrahydroderivatives of E (tetrahydrocortisone, THE) and F (tetrahydrocortisol, THF), formed in separate hepatic compartments by reduction of the A ring. Inadequate HPA axis suppression is frequently encountered in peripubertal CAH patients receiving cortisone acetate therapy. In this paper, we describe THE and THF concentration in 24 h urine samples collected every 3-6 months from 14 prepubertal patients with simple virilizing CAH. The patients had been receiving cortisone acetate and 9 alpha-fluorohydrocortisone since diagnosis and were investigated for 2-4 years during which there was marked intra- and inter-individual variation in the level of suppression. Good and poor control of HPA axis suppression were defined on the basis of a profile of early morning serum 17-hydroxyprogesterone, androstenedione, plasma renin activity and 24 h urinary excretion of pregnanetriol, pregnanetriolone and 5 beta, 17 alpha-hydroxypregnanolone. Serum steroids were measured by RIA and urinary metabolites quantitated as methyloxime-trimethylsilylimidazole derivatives by gas chromatography and GC-mass spectrometry. There were no significant differences in the THE/THF ratio between male (n = 9) and female (n = 5) patients during either good or poor therapeutic control. The data were therefore analyzed without consideration of patient sex. Urinary THE/THF (mean +/- SD) was significantly higher in patients during periods of poor control (6.56 +/- 2.51, P less than 0.001) compared with periods of good control (3.73 +/- 0.96) in the same patients. THE/THF levels were also significantly (P less than 0.001) higher in CAH patients, irrespective of the level of control, than those for the normal subjects (1.79 +/- 0.20). Furthermore, THE excretion was significantly higher during periods of poor control compared with good control at all doses of cortisone acetate administered (10-50 mg/day). There were no significant differences in THF excretion. THE levels also rose significantly (P less than 0.001) in response to increasing total dose during periods of poor control. The increase in THF excretion was slight and significant only at doses greater than 40 mg/day compared with doses less than 15 mg/day.(ABSTRACT TRUNCATED AT 400 WORDS)

A longitudinal evaluation of dexamethasone and cortisol plasma concentrations in the dexamethasone suppression test before and during treatment with antidepressant drugs

Thirty depressed in- and outpatients received serial dexamethasone suppression tests (DSTs). Plasma dexamethasone and cortisol concentrations were drawn at 1600 on the day following a 1-mg oral dose of dexamethasone. The first DST was performed after patients were drug-free for a period of 1 week; the second, third, and fourth DSTs while patients received antidepressant medication. Dexamethasone and cortisol concentrations drawn in the drug-free period correlated significantly. The cortisol to dexamethasone ratio changed significantly with time in DST nonsuppressors, suggesting that nonsuppression is associated with an altered pharmacodynamic response of the hypothalamopituitary-adrenal axis to dexamethasone during depression. When dexamethasone concentrations from the drug-free period were compared with those drawn during antidepressant treatment, no significant differences were noted.

A robust assay for dexamethasone in plasma using a heterologous 125I radioligand and a magnetizable solid-phase antiserum

An assay using an antiserum raised against a dexamethasone 21-hemisuccinate conjugate and the heterologous radioligand dexamethasone 21-(carboxymethyl) ether was developed, validated, and used to study the pharmacokinetics of this steroid for 12 h following administration to patients with congenital adrenal hyperplasia. Coupling the antiserum to magnetizable cellulose allowed rapid separation of bound/free steroid. A C-21 rather than a C-3 antiserum was used to minimize interference with a main metabolite, 6 beta-hydroxydexamethasone. Close correspondence of assay (0.35 nmol/L) and curve (0.25 nmol/L) sensitivities suggests that interference by matrix effects is minimal. This was confirmed by good agreement in data from the in-house assay and that of a reference procedure. Good precision was demonstrated by the precision profile and Shewhart chart quality control data. The latter also demonstrated the assay was robust and reliable in routine practice.

Labeling of hepatic glycogen after short- and long-term stimulation of glycogen synthesis in rats injected with 3H-galactose

The effects of short- and long-term stimulation of glycogen synthesis elicited by dexamethasone were studied by light (LM) and electron (EM) microscopic radioautography (RAG) and biochemical analysis. Adrenalectomized rats were fasted overnight and pretreated for short- (3 hr) or long-term (14 hr) periods with dexamethasone prior to intravenous injection of tracer doses of 3H-galactose. Analysis of LM-RAGs from short-term rats revealed that about equal percentages (44%) of hepatocytes became heavily or lightly labeled 1 hr after labeling. The percentage of heavily labeled cells increased slightly 6 hr after labeling, and unlabeled glycogen became apparent in some hepatocytes. The percentage of heavily labeled cells had decreased somewhat 12 hr after labeling, and more unlabeled glycogen was evident. In the long-term rats 1 hr after labeling, a higher percentage of heavily labeled cells (76%) was observed compared to short-term rats, and most glycogen was labeled. In spite of the high amount of labeling seen initially, the percentage of heavily labeled hepatocytes had decreased considerably to 55% by 12 hr after injection; and sparsely labeled and unlabeled glycogen was prevalent. The EM-RAGs of both short- and long-term rats were similar. Silver grains were associated with glycogen patches 1 hr after labeling; 12 hr after labeling, the glycogen patches had enlarged; and label, where present, was dispersed over the enlarged glycogen clumps. Analysis of DPM/mg tissue corroborated the observed decrease in label 12 hr after administration in the long-term animals. The loss of label observed 12 hr after injection in the long-term pretreated rats suggests that turnover of glycogen occurred during this interval despite the net accumulation of glycogen that was visible morphologically and evident from biochemical measurement.

Plasma dexamethasone concentrations and the dexamethasone suppression test

Altered bioavailability or altered pharmacokinetics of dexamethasone (dex) may contribute to a positive Dexamethasone Suppression Test (DST) in psychiatric patients. We measured plasma dex and plasma cortisol concentrations in 32 patients with primary major depressive disorder (MDD), 14 patients with other psychiatric disorders, and 16 normal controls. Cortisol was measured by the competitive protein binding (CPB) assay and dex by RIA (IgG Corp.). Additionally, cortisol was measured by a fluorescent polarization immunoassay (FPIA) available on the Abbott TDx analyzer in an attempt to validate this method for use in the DST. The agreement between FPIA and CPB cortisol results was excellent. Depressed nonsuppressors, by definition, had significantly higher mean plasma cortisol concentrations than depressed suppressors, psychiatric controls, and normal volunteers at 8:00 AM, 3:00 PM, and 10:00 PM postdex. When DST nonsuppressors and suppressors were compared regardless of diagnostic group, plasma dex concentrations were significantly lower (p less than 0.01) in the DST nonsuppressors. There was a significant negative correlation between plasma cortisol levels and plasma dex levels across all subjects at 8:00 AM (r = -0.365, n = 44, p less than 0.05). When the subjects were sorted by diagnostic category, there was a strong, but not statistically significant, trend toward lower plasma dex concentrations in the melancholic nonsuppressors versus the melancholic suppressors and between the psychiatric control non-suppressors and the corresponding suppressor group. These relationships disappeared when we restricted our analyses to an empirically derived middle range of plasma dex concentrations within which the DST results were considered to be valid. We conclude that bioavailability or pharmacokinetics of dex may significantly contribute to DST results. Further investigation is needed to determine whether or not the quantification of dex and its metabolites and their determination at which specific timepoints during the DST will enhance the predictive or interpretive value of the DST in psychiatric patients.

Prenatal treatment of congenital adrenal hyperplasia: report of a new case

A mother at risk for 21-hydroxylase deficiency was treated with oral dexamethasone (0.5 mg 12 hourly) from early pregnancy, in an attempt to prevent in utero virilization in case of a female fetus. Fetal karyotype was 46,XX, and because of a possible intra HLA recombination, treatment was continued to term. The newborn had a modest virilization and hormonal studies confirmed the diagnosis of congenital adrenal hyperplasia (CAH). This observation and review of the literature suggest that efficient prenatal treatment of CAH requires a higher and more frequent dosage of dexamethasone.

Direct radioimmunoassay procedure for plasma dexamethasone with a sensitivity at the picogram level

A simple radioimmunoassay (RIA) for the direct quantitation of plasma dexamethasone (DEX) at the picogram level has been developed. An antiserum with high specificity and avidity was obtained by the immunization of a carefully synthesized dexamethasone-21-succinyl-thyroglobulin with a high incorporation ratio. As little as 1 pg of DEX in 50 microL of plasma sample can be detected directly by this RIA without extraction and other purification procedures. Intra- and interassay coefficients of variation were 2.1 and 3.3% for plasma levels at 2.93 ng/mL or 2.3 and 7.2% for plasma levels at 0.88 ng/mL. Blank values for plasma of normal or pre-DEX patients were always under the detection limit (20 pg/mL). Excellent linearity (r = 0.9991-0.9999) was demonstrated between the serial dilutions of six plasma samples and their corresponding DEX concentrations. In single-dose DEX (0.25-1 mg) pharmacokinetic studies, plasma DEX was consistently detectable up to 24 h post dose. Compared with existing methods, this direct RIA demonstrates superior performance with regard to simplicity, sensitivity, specificity, and reproducibility. It also enables high sample throughput and has proven robust in our hands. This assay should be readily transferable to other laboratories for clinical or research purposes.

Specific determination of plasma dexamethasone by HPLC and RIA--application to standard dexamethasone suppression test in psychiatric patients

Three radioimmunoassays (RIA), with or without preparative HPLC, were applied to the monitoring of plasma dexamethasone (DXM) levels during standard dexamethasone suppression test (DST) in psychiatric patients. Due to the robotic ease of the fully automated HPLC process, precision of the chromatographic assay was equivalent to that of the direct assays, but prepurification improved both sensitivity and specificity. These improvements allowed the elucidation of the following features: (1) half (36) of the patients (68) displayed infranormal DXM levels (less than or equal to 0.40 ng/ml) whatever the cortisol response; (2) 22% (15) patients (68) with DXM levels in the low control range showed a strong inhibition of cortisol suppression. These observations raise some doubts on the validity of the DST test and introduce the following questions. (1) What is the dependence of cortisol suppression upon DXM absorption and catabolism? (2) Does plasma DXM measurement several hours after its physiological action still reflect its effect on the hypothalamo-hypophyseal axis? (3) What is the reliability of DXM direct assays when measuring low DXM levels in the presence of high cortisol?

Prenatal treatment in congenital adrenal hyperplasia due to 21-hydroxylase deficiency: up-date 88 of the French multicentric study

A multicentric study of prenatal treatment of congenital adrenal hyperplasia (CAH) resulting from 21-hydroxylase deficiency in 43 pregnancies at risk for CAH is presented. The mothers were given dexamethasone per os, 0.5 mg either 12-hourly or 8-hourly. From the analysis of the results obtained in the present study and review of the literature, it would appear that the first condition for successful prevention of female virilization in utero (a total of 6 cases) is to start treatment as early as possible, no later than the 7th week. The dose of dexamethasone should be related to maternal size: 20 micrograms/kg/day (in 2 or 3 fractioned) doses would seem to be both efficient and safe. Adrenal suppression of both maternal and fetal adrenal function should be controlled by appropriate hormonal determinations. Finally, the advantages of early prenatal diagnosis or no prenatal diagnosis are discussed.

Phenytoin-induced resistance to pancuronium. Use of atracurium infusion in management of a neurosurgical patient

A case report is presented of a patient receiving chronic phenytoin therapy who demonstrated resistance to pancuronium by increased hourly requirements. Stable neuromuscular blockade was achieved by atracurium infusion at normal rates. Possible explanations for the differences in response to the two non-depolarizing muscle relaxants are discussed.

Cutaneous and immunologic reactions to phenytoin

Phenytoin (diphenylhydantoin; Dilantin) is a highly effective and widely prescribed anticonvulsant and antiarrhythmic agent. Since 1938 it has been invaluable in the treatment of grand mal and psychomotor epilepsy. Hydantoin derivatives have been used medicinally for more than a half-century. In recent years dermatologists have broadened the indications for phenytoin use to include recessive dystrophic epidermolysis bullosa, linear scleroderma, and pachyonychia congenita. In spite of widespread use and popularity, it is interesting that the frequency of complications relating to drug therapy remains low, relatively speaking. Nevertheless, a broad spectrum of cutaneous and immunologic reactions to phenytoin have been reported. These range from tissue proliferative syndromes (side effects), drug hypersensitivity syndromes (allergic effects), and a possible linkage with lymphoma (idiosyncratic effects). Therapeutic and toxic reactions to this commonly prescribed drug are comprehensively reviewed, analyzed, and summarized in this monograph.

Chronic administration of tricyclic antidepressants suppresses hypothalamo-pituitary-adrenocortical activity in male rats

The effect of chronic administration of the clinically effective antidepressants, imipramine, clomipramine and desipramine, on corticosterone (CS) release in male rats was investigated. Chronic administration of imipramine, clomipramine and desipramine at a dose of 20 mg/kg b.w./day, but not at a dose of 2 mg/kg b.w./day, suppressed blood CS concentration at 2000h and abolished its circadian rhythm. The normal circadian rhythm of CS release resumed seven days after the termination of imipramine injection. The acute administration of imipramine (20 mg/kg b.w./day) at 0800h but not at 2000h elevated CS concentrations. Chronic administration of imipramine (20 mg/kg b.w./day) tended to increase the inhibitory effect of dexamethasone on CS release. Adrenocortical sensitivity to exogenous adrenocorticotropic hormone tended to be decreased by chronic administration of imipramine (20 mg/kg b.w./day). These results indicate that antidepressants have effects on the hypothalamo-pituitary-adrenocortical axis which may confound psychoneuroendocrinological tests, such as the dexamethasone suppression test, for the diagnosis of affective disorders.

Dexamethasone bioavailability: implications for DST research

The bioavailability of dexamethasone (DEX) has recently been demonstrated to be a critical factor in determining Dexamethasone Suppression Test (DST) status in psychiatric patients. This brief review focuses on several aspects of DEX bioavailability as they relate to the use of the DST in neuroendocrine research. Several methodologies, including radioimmunoassay, high-performance liquid chromatography, and gas chromatography-mass spectrometry are available for quantification of DEX in biological fluids, although few detailed comparisons between methods have been reported. Surprisingly, little systematic research on the metabolism of DEX has been reported, but it appears that hepatic rather than renal mechanisms are the major source of DEX elimination. The marked variability in serum DEX levels following oral administration in psychiatric patients is also observed in normal controls and patients with Cushing's syndrome. A variety of drugs can modify serum DEX levels and thereby after the effectiveness of DEX in suppressing serum cortisol levels. Simultaneous measurement of serum DEX and cortisol levels appears to be necessary for the appropriate evaluation of DST results. This procedure may help explain many of the inconsistencies in recent DST research.

Corticosteroid therapy in adolescent patients

Since their introduction in the 1950s, corticosteroids have become an important adjunct in the therapy for a wide variety of diseases. Improved guidelines for clinical applications and for reduction in undesirable effects have been achieved through a better understanding of corticosteroid mechanisms of action and pharmacokinetic properties. This discussion will review the indications and adverse effects associated with corticosteroid therapy. Emphasis will be placed on the important aspects of corticosteroid therapy in adolescent patients including recent advances essential to the development of guidelines for dosing and therapeutic monitoring.

The biotransformation and urinary excretion of dexamethasone in equine male castrates

The pro-drugs of dexamethasone, a potent glucocorticoid, are frequently used as anti-inflammatory steroids in equine veterinary practice. In the present study the biotransformation and urinary excretion of tritium labelled dexamethasone were investigated in cross-bred castrated male horses after therapeutic doses. Between 40-50% of the administered radioactivity was excreted in the urine within 24 h; a further 10% being excreted over the next 3 days. The urinary radioactivity was largely excreted in the unconjugated steroid fraction. In the first 24 h urine sample, 26-36% of the total dose was recovered in the unconjugated fraction, 8-13% in the conjugated fraction and about 5% was unextractable from the urine. The metabolites identified by microchemical transformations and thin-layer chromatography were unchanged dexamethasone, 17-oxodexamethasone, 11-dehydrodexamethasone, 20-dihydrodexamethasone, 6-hydroxydexamethasone and 6-hydroxy-17-oxodexamethasone together accounting for approx 60% of the urinary activity. About 25% of the urinary radioactivity associated with polar metabolites still remains unidentified.

Identification and quantification of 6 beta-hydroxydexamethasone as a major urinary metabolite of dexamethasone in man

Identification of 6 beta-hydroxydexamethasone as a major urinary metabolite of dexamethasone in man has been accomplished by nuclear magnetic resonance spectroscopy and gas chromatography-mass spectrometry. Mass fragmentographic measurements revealed that more than 30% of the intravenously or orally administered dexamethasone dose was excreted in the 24-h urine as 6 beta-hydroxydexamethasone, while only a small fraction of the dose was excreted as unchanged dexamethasone and its glucuronic acid conjugate.

False-positive results in the radioimmunoassay detection of stilbene derivatives after administration of fluorinated corticosteroids to animals

During routine inspections, indications were found that the therapeutic use of fluocortolone or dexamethasone can cause false-positive results in the detection of stilbene derivatives by radioimmunoassay (RIA) in samples of animal origin. After experimental application of the fluorinated corticosteroids to rabbits or calves, the assumed false-positive RIA results were confirmed. The kinetics after application of dexamethasone were concomitant with the elimination of radioactive [3H]dexamethasone. Furthermore, it could be demonstrated that [3H]dexamethasone was transformed in the faeces of rabbits and calves. The metabolites formed were not completely separated by the extraction procedure used for the RIA and seemed to be responsible for the false-positive results.

Anticonvulsant therapy and cortisol elimination

The effect of anticonvulsant therapy on early morning concentration of cortisol in saliva and plasma was assessed in a group of epileptic patients receiving regular phenytoin medication and the results compared with those obtained from a group of normal subjects not receiving drug therapy. Values of cortisol in matched samples of plasma (331 +/- 23 nmol l-1, mean +/- s.e. mean, n = 6) and saliva (11.4 +/- 0.9 nmol l-1, mean +/- s.e. mean, n = 9) provided by epileptics did not differ significantly from those in the plasma (334 +/- 41 nmol l-1, mean +/- s.e. mean) and saliva (12.0 +/- 2.0 nmol-1, mean +/- s.e. mean) of healthy volunteers (n = 12). Six anticonvulsant-treated epileptics, together with six age and sex matched normal volunteers, each received intravenous dexamethasone (1 mg h-1) to determine the half-life of cortisol in plasma and saliva. In the anticonvulsant-treated group, the half-life of cortisol in plasma (73 +/- 5 min, mean +/- s.e. mean) and saliva (83 +/- 5 min, mean +/- s.e. mean) was reduced significantly (P less than 0.01 plasma, P less than 0.05 saliva) from that observed in healthy volunteers. In patients, the half life of cortisol and antipyrine showed a significant correlation (r2 = 0.75, P less than 0.05 plasma, r2 = 0.71, P less than 0.05 saliva). The antipyrine half-life in saliva was reduced significantly (P less than 0.02) and the antipyrine clearance rate, increased significantly (P less than 0.005) in the treated epileptic group, reflecting drug-induced microsomal enzyme production.(ABSTRACT TRUNCATED AT 250 WORDS)

Disregulation of hypothalamic-pituitary-adrenal axis in the mentally retarded

Previous reports of cognitive and social improvement in the mentally retarded after administration of MSH/ACTH fragments suggested disregulation of the hypothalamic-pituitary-adrenal (HPA) axis. The current study examined the integrity of this system with the Dexamethasone Suppression Test (DST). The DST is a biological index of HPA integrity and recently has been used as a diagnostic aid for endogenous depression. Thirty-five mentally retarded patients were administered 1 mg of dexamethasone just after a sample of blood was taken. Blood samples were analyzed for cortisol by RIA at 11:00 p.m. (basal), 8:00 a.m., 4:00 p.m., and 10:00 p.m. Between 40% and 48% (depending on sampling) of the patients failed to suppress cortisol (greater than 4 micrograms/dl), after the DST challenge. The results suggested that a significant proportion of mentally retarded patients have a DST index reflecting a disordered HPA axis and complements earlier studies of cognitive enhancement observed after treatment with MSH/ACTH fragments. The possibility that the stress of hospitalization was related to a disordered HPA was suggested. The possible co-existence of depression in the mentally retarded invites further study.

A new defect in the peripheral conversion of cortisone to cortisol

A steroid disorder is described in two sisters, aged 13 and 17 years, in which the metabolism of cortisol results almost exclusively in urinary excretion of tetrahydro-cortisone (11-keto) derivatives. The evidence implies the existence of a deficiency in the peripheral enzymatic conversion of cortisone to cortisol.

On the interaction between phenytoin and digoxin

An open, randomized, single-blind cross over trial to investigate phenytoin-digoxin interactions at steady state was performed in 6 healthy male volunteers. Coadministration of phenytoin caused a significant reduction in the elimination half-life of digoxin from 33.9 to 23.7 h and a diminution in AUC0-48 from 31.6 to 24.4 ng X ml-1 X h. Renal digoxin clearance was not significantly altered from 135.7 to 120.3 ml X min-1. Assuming no change in beta-acetyldigoxin absorption, the in decrease time-course the serum digoxin concentration was due to a significantly increased total digoxin clearance from 258.6 to 328.3 ml X min-1. An insignificant reduction in the digoxin distribution volume from 749.4 to 668.0 l was also observed. No relevant change in the pharmacokinetic parameters (elimination half-life, area under the serum concentration time-curve, protein binding) of phenytoin was observed when phenytoin and digoxin were co-administered. The data suggest that with this drug combination the serum digoxin concentration should be carefully monitored and, if necessary, the daily digoxin dose should be increased.

Plasma corticosterone and cortisol following dexamethasone in psychiatric patients

Radioimmunoassays of cortisol (F) and corticosterone (B) were carried out in 133 plasma specimens, obtained at 0800 or 1600 h on the day following administration of dexamethasone (1.0 mg), from 69 patients admitted to a psychiatric inpatient service, to test suggestions that assays of B might complement those of F in the dexamethasone suppression test (DST) in a psychiatric setting. The overall correlation between F and B was +0.80. Concentrations of B averaged 5-8% those of F. We found close agreement (80-85%) between positive (F greater than or equal to 4.5 micrograms/dl) and negative DST results for both steroids assayed by radioimmunoassay at a criterion of greater than or equal to 1.5 ng/ml for B, as well as a reasonable compromise between sensitivity and specificity of the B-DST at that criterion. Post-dexamethasone samples obtained at 1600 h showed somewhat closer agreement between the B-DST and the F-DST than at 0800 h. Inclusion of 0800 h samples added little to the rate of positive results with the F-DST but did add to those of the B-DST by about 10% or more, depending on the criterion selected for a positive B-DST. The rate of positive DSTs among 44 patients who had both steroids assayed at both times was approximately 61%, and the agreement between positive test results among these patients was 92%. In a mixed population of acutely ill, hospitalized patients with various DSM-III diagnoses, but excluding those with medical or pharmacologic contraindications to the DST, high rates of positive DST results were obtained in patients with major depressive disorders (47-58%), with little difference found among those with bipolar, non-bipolar or melancholic characteristics. High rates also were found among manic and other acutely psychotic patients, as well as others with neurotic or characterological diagnoses, but rarely in a small group of chronic schizophrenics. Thus, a positive DST as evaluated with B or F is evidently not specific for cases of major depression, but may be indicative of acute illness, possibly with affective features. The results support suggestions that a steroid suppression test based on corticosterone may be useful to aid in diagnosis of major psychiatric illnesses and might complement or substitute for the F-DST. It may be possible to avoid certain pharmacologic complications in the DST by use of a test based on suppression of B by F rather than by dexamethasone.

Cortisol and dexamethasone elimination during treatment with cimetidine

In a randomised cross-over study of treatment for 7 days with cimetidine 600 mg twice daily and placebo, cimetidine had no effect on the pharmacokinetics of a single intravenous dose of dexamethasone sodium phosphate. Likewise the elimination characteristics of endogenous cortisol in the dexamethasone suppressed state were not affected by cimetidine.