Patients' Individualized Care Perceptions and Health Literacy Using an Interactive App During Breast and Prostate Cancer Treatment: Two Parallel Randomized Controlled Trials

The use of symptom management mobile apps can reduce patients' symptom burden during cancer treatment, but the evidence is lacking about their effect on care. Moreover, if patients' health literacy can be improved, it needs to be more rigorously tested. This study aimed to evaluate patients' perceptions of individualized care and health literacy using an interactive app in two randomized trials. Patients undergoing neoadjuvant chemotherapy for breast cancer (N = 149) and radiotherapy for prostate cancer (N = 150) were consecutively included and randomized into one intervention or control group. Outcome measures were Individualized Care Scale, Swedish Functional Health Literacy Scale, and Swedish Communicative and Critical Health Literacy Scale. In the breast cancer trial, no group differences were observed regarding individualized care or health literacy. Most patients had sufficient health literacy levels. In the prostate cancer trial, intervention group patients rated higher perceived individualized care regarding decision control at follow-up than the control group. Less than half had sufficient health literacy levels and intervention group patients significantly improved their ability to seek, understand, and communicate health information. Education level explained significant variance in health literacy in both trials. Using an interactive app can positively affect individualization in care and health literacy skills among patients treated for prostate cancer, although further research is warranted.

Sexual Satisfaction and Associated Biopsychosocial Factors in Stroke Patients Admitted to Specialized Cognitive Rehabilitation

Introduction

The consequences of stroke on sexual life in stroke patients in need of specialized cognitive rehabilitation have been limited explored. A biopsychosocial perspective in post-stroke sexuality studies is warranted to capture the complex picture of stroke consequences and sexual life after stroke and sexual satisfaction is an important outcome measure when exploring such multifactorial associations.

Aim

To explore sexual satisfaction and associated biopsychosocial factors in stroke patients admitted to specialized cognitive rehabilitation.

Methods

A cross-sectional study was performed including 91 consecutive stroke patients admitted to specialized cognitive rehabilitation. Data were collected from medical records and by face-to-face interviews using a structured interview guide and questionnaires. Descriptive and inferential statistics were applied.

Main outcome measures

A wide range of biopsychosocial variables including medical and sociodemographic characteristics, social support, sexual complaints, aspects of sexual life, psychological distress and life satisfaction were analyzed in relation to the main outcome “Satisfaction with sexual life.”

Results

Only 33 % were satisfied with sexual life. Prevalence of sexual complaints was high, more frequent in women (84%) than in men (64%). Three-quarters were less sexually active than before stroke. Multivariable analyses showed that anxiety, sleep problems, manifested sexual complaint, decrease in sexual activity and fear of partner rejection were significantly associated with low odds of sexual satisfaction, while affectionate support and partnership satisfaction were significant for sexual satisfaction. When combined in a biopsychosocial multivariable model only fear of partner rejection (OR 0.07; 95 % CI: 0.01–0.42) and decrease in sexual activity (OR 0.11; 95 % CI: 0.02–0.58) showed significant contribution to sexual satisfaction.

Conclusion

The variety of predictors for sexual satisfaction indicates that therapeutic actions need to be individualized and points towards a broad assessment and interventional approach to meet the sexual rehabilitation needs of stroke patients with cognitive impairments in need of specialized rehabilitation.

Vikan JK, Snekkevik H, Nilsson MI, et al. Sexual Satisfaction and Associated Biopsychosocial Factors in Stroke Patients Admitted to Specialized Cognitive Rehabilitation. Sex Med 2021;9:100424.

A study to examine the influence of health professionals' advice and support on work capacity and sick leave after breast cancer surgery

PURPOSE

The aim of this study was to investigate how women, shortly after breast cancer surgery, experienced encounters with, and information from, healthcare professionals regarding work and sick leave and if these experiences were associated with self-reported work capacity and sick leave.

METHODS

This is a cross-sectional study based on questionnaire data from 605 women who had had breast cancer surgery, aged 20-63 years. Exclusion criteria were known distant metastases, pre surgical therapy, and/or previous breast cancer. Data on age, type of surgery, global health, and work environment were included as covariates in multivariable logistic regression analysis.

RESULTS

Five percent of the women had not received any advice concerning work or sick leave. Women reporting receiving useful advice or support related to paid work had lower risk of reporting reduced physical or psychological/social work capacity due to the cancer or treatment (OR 0.46 (95 % CI 0.26-0.81) respective OR 0.45 (95 % CI 0.26-0.77)). There were no associations between having received useful advice or support concerning work and being on sick leave. Women encouraged to take sick leave had an OR of 2.17 (95 % CI 1.39-3.37) of being sickness absent. They also to a higher extent had reduced physical and psychological/social work capacity. Women who reported to have been encouraged to work were sickness absent to a lower extent (OR 0.64; 95 % CI 0.41-0.98) and reported higher physical work capacity.

CONCLUSIONS

Work and sick leave is being discussed during consultations with women with breast cancer and the advice given seems to be in line with the women's subjective work capacity.

Combined aerobic exercise and enzyme replacement therapy rejuvenates the mitochondrial-lysosomal axis and alleviates autophagic blockage in Pompe disease

A unifying feature in the pathogenesis of aging, neurodegenerative disease, and lysosomal storage disorders is the progressive deposition of macromolecular debris impervious to enzyme catalysis by cellular waste disposal mechanisms (e.g., lipofuscin). Aerobic exercise training (AET) has pleiotropic effects and stimulates mitochondrial biogenesis, antioxidant defense systems, and autophagic flux in multiple organs and tissues. Our aim was to explore the therapeutic potential of AET as an ancillary therapy to mitigate autophagic buildup and oxidative damage and rejuvenate the mitochondrial-lysosomal axis in Pompe disease (GSD II/PD). Fourteen weeks of combined recombinant acid α-glucosidase (rhGAA) and AET polytherapy attenuated mitochondrial swelling, fortified antioxidant defense systems, reduced oxidative damage, and augmented glycogen clearance and removal of autophagic debris/lipofuscin in fast-twitch skeletal muscle of GAA-KO mice. Ancillary AET potently augmented the pool of PI4KA transcripts and exerted a mild restorative effect on Syt VII and VAMP-5/myobrevin, collectively suggesting improved endosomal transport and Ca(2+)- mediated lysosomal exocytosis. Compared with traditional rhGAA monotherapy, AET and rhGAA polytherapy effectively mitigated buildup of protein carbonyls, autophagic debris/lipofuscin, and P62/SQSTM1, while enhancing MnSOD expression, nuclear translocation of Nrf-2, muscle mass, and motor function in GAA-KO mice. Combined AET and rhGAA therapy reactivates cellular clearance pathways, mitigates mitochondrial senescence, and strengthens antioxidant defense systems in GSD II/PD. Aerobic exercise training (or pharmacologic targeting of contractile-activity-induced pathways) may have therapeutic potential for mitochondrial-lysosomal axis rejuvenation in lysosomal storage disorders and related conditions (e.g., aging and neurodegenerative disease).

Adjustment and social support at work early after breast cancer surgery and its associations with sickness absence

INTRODUCTION

As half of the women with breast cancer are of working ages and usually survive, knowledge is needed on how to support them early regarding work-related problems caused by treatments. Most previous studies have focused on individual and disease-related factors, whereas few have focused on work-related factors such as work adjustment and social support. The aim of this study was to investigate received and perceived social support from supervisor and colleagues as well as work adjustments, and their associations with sickness absence, among women who recently had had breast cancer surgery.

METHOD

Inclusion criteria were as follows: women aged 20-63 years, living in Stockholm County, treated surgically for a first diagnosis of breast cancer, literate in Swedish, without pre-surgical chemotherapy or known distant metastases. Included in the study were 605 women who worked at diagnosis and that had answered a questionnaire within eight weeks of inclusion. Descriptive statistics, univariate, and multivariable logistic regression analyses were applied to estimate odds ratios (OR) with 95% confidence intervals (CI) for the likelihood of being sickness absent.

RESULTS

Most women perceived and received social support and work adjustment after breast cancer surgery. Low adjustment (OR = 2.14; 95% CI, 1.45-3.18) and less social support (OR = 1.80; 95% CI, 1.16-2.78) were significantly associated with being sickness absent. Adjusting for sociodemographics, strenuous work posture, and treatment did not attenuate these associations.

CONCLUSION

Adjustment at work and social support from employer are associated with sickness absence and needs to be explored in discussions on return to work after breast cancer surgery.

Women's reflections and actions regarding working after breast cancer surgery - a focus group study

BACKGROUND

To better understand processes affecting return to work (RTW) after breast cancer, more knowledge from the perspective of sickness absentees is warranted. Still, research based on women's own reasoning and actions in RTW is very scarce. This study aims to elucidate how women with breast cancer reflect and act on work-related issues.

MATERIAL AND METHODS

Thematic analyses of data from four focus group interviews with 23 women who had had breast cancer surgery in the previous 3-13 months were carried out.

RESULTS

The five following themes of reflections regarding RTW were identified: 'health and functioning', 'self-esteem/integrity', 'value of work', 'relationships at work', and 'social circumstances'. These reflections were associated with the three identified themes of actions taken by the women: 'to work or to be sickness absent', 'to adjust work according to own needs or not', and 'to disclose or to hide one's cancer'. There was a distinct difference between women who experienced work as a source of well-being and those who needed a respite from work.

CONCLUSION

This study adds knowledge to the process of RTW after breast cancer and focuses on factors that lead the women to an active role in this process. We point to the interplay between women's own preferences, perceived competence, outer opportunities, and the actions each woman take with regard to RTW, which need to be recognized by all stakeholders involved. Furthermore, it continues to be essential to address the specific issue of disclosure in the workplace because this may be distressing for women.

Simulated resistance training, but not alendronate, increases cortical bone formation and suppresses sclerostin during disuse

Mechanical loading modulates the osteocyte-derived protein sclerostin, a potent inhibitor of bone formation. We hypothesized that simulated resistance training (SRT), combined with alendronate (ALEN) treatment, during hindlimb unloading (HU) would most effectively mitigate disuse-induced decrements in cortical bone geometry and formation rate (BFR). Sixty male, Sprague-Dawley rats (6-mo-old) were randomly assigned to either cage control (CC), HU, HU plus either ALEN (HU+ALEN), or SRT (HU+SRT), or combined ALEN and SRT (HU+SRT/ALEN) for 28 days. Computed tomography scans on days -1 and 28 were taken at the middiaphyseal tibia. HU+SRT and HU+SRT/ALEN rats were subjected to muscle contractions once every 3 days during HU (4 sets of 5 repetitions; 1,000 ms isometric + 1,000 ms eccentric). The HU+ALEN and HU+SRT/ALEN rats received 10 μg/kg ALEN 3 times/wk. Compared with the CC animals, HU suppressed the normal slow growth-induced increases of cortical bone mineral content, cortical bone area, and polar cross-sectional moment of inertia; however, SRT during HU restored cortical bone growth. HU suppressed middiaphyseal tibia periosteal BFR by 56% vs. CC (P < 0.05). However, SRT during HU restored BFR at both periosteal (to 2.6-fold higher than CC) and endocortical (14-fold higher than CC) surfaces (P < 0.01). ALEN attenuated the SRT-induced BFR gains during HU. The proportion of sclerostin-positive osteocytes in cortical bone was significantly higher (+121% vs. CC) in the HU group; SRT during HU effectively suppressed the higher proportion of sclerostin-positive osteocytes. In conclusion, a minimum number of high-intensity muscle contractions, performed during disuse, restores cortical BFR and suppress unloading-induced increases in sclerostin-positive osteocytes.

Pharmacokinetics and effects on prolactin of remoxipride in patients with tardive dyskinesia

The pharmacokinetics of remoxipride, a new selective dopamine-D2 receptor antagonist with antipsychotic action, was evaluated in eight elderly psychiatric patients with tardive dyskinesia (TD). The daily oral doses of remoxipride were gradually increased from 50 mg per day to 200 mg t.i.d. over 2 weeks. The pharmacokinetics following the initial 50 mg dose (day 1) and the last 200 mg dose (day 15) of the drug were compared in serial samples. Plasma prolactin concentrations were assessed at the same time points. The area under the total plasma concentration versus time curves (AUC) of remoxipride increased proportionally with dose from day 1 to 15. The mean "dose corrected" AUC values for the total concentrations were 96.8 at day 1 (4 X 24.2, 50 mg single oral dose) and 92.2 mumol.h/l at day 15 (200 mg). The unbound fraction of remoxipride calculated on AUC was slightly higher on day 15 (20%) than on day 1 (15%) (P less than 0.05), indicating slightly concentration-dependent protein binding of the drug. The mean elimination half-life of total remoxipride was slightly longer on day 15 than day 1 (7.5 versus 5.3 h, P less than 0.01) The corresponding half-lives for the unbound concentrations were 6.4 and 3.9 h, respectively (P less than 0.01). The pharmacokinetics of remoxipride is similar in these TD patients and in non-TD patients in previous studies. Following repeated administration of remoxipride, tolerance to the prolactin-releasing action of remoxipride is observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Plasma concentrations of remoxipride and the gastrointestinal transit of 111In-marked extended-release coated spheres

To explore the oral absorption of remoxipride, spheres of remoxipride were labeled with indium-111 colloid before coating with a release-controlling ethylcellulose membrane. Since the labeling remained inside the coating, it was suitable as a marker. Eight healthy volunteers were given a single dose of 100 mg remoxipride in 111In-marked spheres as a multiple-unit capsule. The radioactivity and the position of the spheres (microcapsules) were followed externally for 30 hr by gamma scintigraphy. Parallel to this, plasma concentrations were drawn for 48 hr to confirm the extended dissolution and absorption of remoxipride. The hard gelatin, multiple-unit capsule released the microcapsules within the stomach. These were then rapidly emptied into the small intestine, within 0.5-1 hr. There was then an immediate distribution in the upper small intestine before collection in the lower portion, within 2-5 hr. After passing into the large intestine, there was again extended distribution of the microcapsules. A mean Cmax of 2.7 microM remoxipride was achieved 4 hr after drug administration and a mean AUC of 26.1 mumol.L-1.hr was achieved. Judging from the absorption versus time profile, calculated according to the Wagner-Nelson method, and the scintigraphic images, it is concluded that the main absorption occurs from the small intestine. Data from four volunteers, however, indicated a comparatively good absorption also from the large intestine. Due to the good absorption properties, it is reasonable to expect a low variation in the extent of bioavailability of remoxipride after administration in an extended-release, multiple-unit capsule formulation.

Remoxipride--a new potential antipsychotic compound. Tolerability and pharmacokinetics after single oral and intravenous administration in healthy male volunteers

The tolerability and pharmacokinetics of remoxipride were studied in 18 healthy normal male volunteers. Increasing oral doses of 0.5-100 mg were given to eight male volunteers in one study (study I). In addition, an intravenous (IV) infusion of 20 mg remoxipride and a 20 mg oral dose were given in an open crossover study to ten males (study II). Remoxipride was well tolerated with respect to cardiovascular effects, clinical chemistry, body temperature and adverse effects in all subjects. Following IV administration, remoxipride plasma concentrations declined exponentially in five subjects and biexponentially in the remaining five. The mean apparent volume of distribution was 0.5 l/kg (SD = 0.10) and the mean half-life 4.1 h (range 2.6-6.6). The recovery of unchanged remoxipride in urine was 10-36%, and the mean renal clearance was 32 ml/min (SD = 13). Remoxipride was a low clearance drug with a total plasma clearance of about 120 ml/min (SD = 41). The mean oral bioavailability was 96%. There was a linear relationship between the peak plasma concentration as well as the area under the concentration versus time curve and the administered dose. A transient increase in plasma prolactin concentrations occurred but there were no effects on plasma growth hormone levels.

Effect of urinary pH on the plasma and urinary kinetics of remoxipride in man

The influence of urinary pH on the plasma and urinary kinetics of remoxipride in man has been studied in an open crossover trial in ten healthy male volunteers. Ammonium chloride (urinary pH 5.2) and sodium hydrogen carbonate (urinary pH 7.8) were used as pretreatments on two occasions in randomized order. On each occasion remoxipride 50 mg solution was administered orally and plasma and urinary concentrations of the drug were determined by HPLC and plasma prolactin concentrations by RIA. Remoxipride was rapidly distributed in the body according to a one-compartment model. The mean plasma elimination half-life (t1/2) was 3.6 h in the ammonium chloride experiment and 6.2 h in the sodium hydrogen carbonate experiment. The mean plasma clearance of remoxipride was 141 and 89.9 ml.min-1 in the acidic and alkaline conditions, respectively, and the corresponding mean renal clearances were 58.5 ml.min-1 and 11.7 ml.min-1. The urinary excretion of remoxipride up to 72 h after drug administration was 43.1% and 12.3% following acidification and alkalinization, respectively. Remoxipride induced a similar rapid, transient elevation of plasma prolactin under both conditions. Thus, the urinary pH has a marked effect on the elimination kinetics of remoxipride. After an overdose, treatment with ammonium chloride might be valuable in hastening elimination of remoxipride from the body.

Remoxipride--a new potential antipsychotic drug. Pharmacological effects and pharmacokinetics following repeated oral administration in male volunteers

Remoxipride, a new potential antipsychotic drug, was administered over 4 days at two dose levels, 70 and 140 mg t.i.d., to eight healthy male volunteers. Pharmacokinetics, safety, tolerability, and effect on plasma prolactin levels were evaluated. Remoxipride exhibited essentially linear pharmacokinetics. Only minor deviations in biochemical and physiological safety parameters were found. The drug was well tolerated by all subjects at the 70 mg dose level. At 140 mg akathisia appeared in seven subjects. The drug induced a rapid and transient increase in plasma prolactin concentrations at both dose levels after single doses. During steady state, a significant reduction in the prolactin response was observed as compared to after the first dose.

Remoxipride, a selective dopamine D2 receptor antagonist, in tardive dyskinesia

Remoxipride in a dose range of 150-600 mg/day was evaluated in a single-blind placebo controlled study in eight patients with persistent tardive dyskinesia (TD). Dyskinesia score was significantly reduced without an increase in parkinsonism. The maximum mean reduction in dyskinesia rating score was 44%. After withdrawal of remoxipride TD scores returned to baseline levels without rebound deterioration. A negative correlation between remoxipride concentrations and the dyskinesia scores were found. Adverse effects were few and mild and no clinically relevant changes were seen in clinical chemistry, haematology or cardiovascular assessments. It is concluded that remoxipride in the dose range used has anti-dyskinetic effects but does not induce parkinsonism.

Pharmacokinetics of methadone in methadone maintenance treatment: characterization of therapeutic failures

Deuterated methadone (M-d3) and GC-MS analysis were used to study the steady state pharmacokinetics of methadone (M) in eight patients reported as therapeutic failures in a methadone maintenance treatment programme. The patients were compared to an unselected group of 12 patients stabilized on M for 25 days. During one dosage interval a pulse dose of M-d3 was administered intravenously instead of the oral M-dose (M-d0). The pharmacokinetic parameters, half-life in the beta-phase (t1/2 beta), volume of distribution during the postdistributive phase (Vd beta) and during steady state (Vdss) were determined as well as the body (ClS) and renal (ClR) clearances of M. Pronounced differences in Vd beta and Vdss were found between the two groups. The therapeutic failures had a smaller Vd beta and Vdss 3.09 +/- 0.96 1/kg and 2.74 +/- 0.96 1/kg vs 4.56 +/- 1.00 1/kg and 4.20 +/- 0.78 1/kg in the control group. The differences were due to changes between the groups in the volume of the central compartment. Differences between the groups were also found in t1/2 beta - 24.5 +/- 2.6 h in the therapeutic failures and 34.0 +/- 7.0 h (p less than 0.001) in the comparison group. However, the change in t1/2 beta was probably a consequence of the change in Vd beta, as the body clearance of M was similar in the two groups - 104 +/- 36 ml/min vs 111 +/- 36 ml/min. The smaller volume of distribution could lead to unacceptably high fluctuation of M in the central compartment, and withdrawal symptoms during the latter part of the dosage interval.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical pharmacokinetics of methadone

Studies with single doses of methadone have shown that the oral biological availability is 79 +/- 21%, range 41-99%. The rate of elimination is mostly due to metabolic clearance. Below a urinary pH of 6, renal clearance becomes of quantitative importance. In five subjects treated with ammonium chloride (acidic urine), the plasma half-life of methadone was found to be 19.5 +/- 3.6 h. When treated with sodium bicarbonate the same subjects had plasma half-lives of 42.1 +/- 8.8 h. During continuous treatment with methadone, cellular tolerance may occur and in some subjects also metabolic tolerance. In treatment of severe cancer pain such adaptive changes in methadone pharmacodynamics and pharmacokinetics are best managed by a regimen involving a fixed dose but a flexible and patient-controlled dosage interval.

Clinical evaluation of oral methadone in treatment of cancer pain

A dose-adjustment program for oral methadone and the long-term effects of the analgesic therapy have been evaluated in 15 patients with incurable cancer. Rapid and continuous pain relief without serious side-effects was achieved by "ad libitum" dosage in the first 3-5 days. Thereafter, a dosage based on each patients's subjective need was instituted. The mean daily dose was 44 during the first day and it decreased to 22 mg daily at the end of the dose-adjustment week. Three patients did not complete the program because of insufficient effect or severe nausea. Among the 12 patients who chose to continue the methadone treatment after the initial dose-adjustment period, four continued the therapy to their death, three discontinued the therapy due to insufficient effect, and three due to adverse reactions. In one case it was possible to stop the treatment due to decreased pain. The treatment period in these 12 patients varied between 8 and 270 days. Oral methadone offers good pain relief for long periods of time in this group of patients and has obvious advantages as compared to long term parenteral therapy with narcotic analgesics.

Pharmacokinetics of methadone during maintenance treatment: adaptive changes during the induction phase

Deuterated methadone (M-d3) and GCMS were used to study the pharmacokinetics of methadone (M) during the induction stage of methadone maintenance treatment (MMT). A pulse dose of M-d3 was given on Days 1 and 25 of two dosage regimens, one with a continuous 30 mg dose (n = 6), and the other with 30 mg for 10 days, followed by 60 mg as the maintenance dose (n = 6). Plasma and urinary levels of M and M-d3 were measured throughout and plasma half-lives, oral bioavailabilities and volumes of distribution were calculated from the data of Days 1-2 and 24-26. The oral bioavailability of a methadone solution was found to be between 81 and 95%: elimination half-life in the beta-phase varied between 19 and 58 h; the volume of distribution was 4.1 +/- 0.65 l/kg; and total body clearance of M was 54-195 ml/min and its renal clearance 3.4-34 ml/min. A consistent finding was a lower urinary pH and increased renal clearance during the first month of treatment. The shorter elimination half-lives in those patients probably caused unacceptably high fluctuation in the body content of M during the 24 h dosage interval, and may have interfered therefore, with its therapeutic effectiveness.

Effect of urinary pH on the disposition of methadone in man

The influence of urinary pH on the acute disposition of methadone in man was studied in five healthy volunteers. A cross-over experiment was performed in each subject. In the first experiment the subjects were treated with ammonium chloride (urinary pH approximately 5.2) and in the other the urine was made alkaline (pH approximately 7.8) by treatment with sodium hydrogen carbonate. d, l-Methadone-HCl 10 mg (M) was administered intramuscularly on each occasion and blood, saliva and urine levels of M were determined by mass fragmentography. Plasma half-lives, volumes of distribution and body clearances of M were calculated in both experiments. The plasma half-lives in the beta-phase were 19.5 +/- 3.6 h (acidic urine) and 42.1 +/- 8.8h (alkaline urine), respectively (p less than 0.001). The volumes of distribution were increased when the pretreatment was changed from ammonium chloride to sodium bicarbonate, namely from 3.51 +/- 0.41 l/kg to 5.24 +/- 0.83 l/kg (p less than 0.01). The body clearance decreased from 134 +/- 21 ml/min (acidic) to 91.9 +/- 9.1 ml/min (alkaline urine) (p less than 0.01). The ration M plasma/M RBC was about 2.3 and the elimination of M from RBCs was good agreement with the plasma kinetics of M under both experimental conditions. The salivary levels of M did not reflect the plasma kinetics and considerable variation was seen in the ratio M saliva/ M plasma (0.26-2.98). Thus, the present experiments demonstrate that pretreatment either with ammonium chloride or bicarbonate had profound effects on both the distribution and elimination kinetics of methadone.

Patient-controlled dose regimen of methadone for chronic cancer pain

Fourteen patients with severe cancer pain participated in a trial of methadone given in a fixed dose (10 mg) but at intervals selected by the patients themselves during the loading phase. The aim was to achieve rapid pain relief while avoiding the risk of toxicity from accumulation of methadone. As expected, the dosage intervals increased gradually over the first few days of treatment, the daily dose decreasing from 30-80 mg on the first day to 10-40 mg at the end of the week. Plasma concentrations of methadone varied sevenfold after four to five days (0.24 to 1.75 mumol/1; 7.4 to 54.2 microgram/100 ml). Eleven patients reported complete or almost complete pain relief and elected to continue with methadone after the study. In no case was treatment withdrawn because of intoxication. From these findings a patient-controlled dosage regimen of oral methadone may be an effective and safe alternative to parenteral narcotic medication, adjusting both for individual variation in pain intensity and for pharmacokinetics.

Single dose pharmacokinetics and bioavailability of methadone in man studied with a stable isotope method

The disposition of methadone was studied in eight opiate dependent subjects during detoxification. Plasma concentrations were determined by mass fragmentography of 48 hours after administration of methadone 20 mg as tablets and simultaneous intravenous injection of deuterium-labelled methadone 20 mg. Pharmacokinetic parameters were calculated for the intravenous dose assuming a two compartment of open model. Bioavailability was determined by comprising the areas under the plasma concentration versus time curves of unlabelled and labelled methadone. The beta-phase plasma half-lives varied five-fold, with a range from 8.5 to 47 h. The apparent volumes of distribution varied from 2.1 to 5.6 l/kg. Five patients had a bioavailability exceeding 90%, and three had lower bioavailabilities of between 41 and 76%. The unlabelled and labelled drug appeared to be pharmacokinetically equivalent. The data show that for a majority of these subjects the bioavailability was higher than 45%, the previously reported value. The marked individual variation in methadone pharmacodynamics and kinetics, and the possibilities both of cellular and metabolic tolerance, require an individually optimized dosage regimen.

Pharmacokinetics of methadone during maintenance therapy: pulse labeling with deuterated methadone in the steady state

A technique is presented for study of steady state kinetics of methadone using pulse labeling with deuterated methadone (d3) and mass fragmentography to measure both unlabeled and labeled methadone in blood. Seven subjects maintained on methadone for at least 10 months were admitted to a closed metabolic ward. The daily dose of unlabeled methadone (d0) was substituted by one dose of methoadone-d3 and plasma levels of methadone-d0 and methadone-d3 were followed for 48 h using a precise (SD +/- 5%) and sensitive (30 pmol/ml) mass fragmentographic technique. Plasma half-lives (T1/2) for both methadone-do and methadone-d3 were calculated from samples obtained 8--24 H following the dose of methadone-d3. The t1/2 of oral methadone-d3 was shorter (22 +/- 2 h) than that of methadone-d0 (52 +/- 20 h). The same pattern was observed after intravenous administration. The results indicate multiple pools of methadone in the body.