Drug-related Changes Research Articles

A 52-week oral toxicity study of a new antineoplastic agent S-1 in dogs

52-week oral repeated-dose S-1 toxicity studies were conducted. Male and female dogs were orally treated with 0, 0.1, 0.5 or 2.5 mg/kg/day for 52 weeks and permitted to recover for 13 weeks. Furthermore, to estimate the no-toxic dose, male and female dogs were given S-1 orally for 52 weeks at doses of 0, 0.004 and 0.02 mg/kg/day. The 2.5 mg/kg/day regimen produced one dead or moribund dog of each sex; black-brown patch (melanin deposition) and inflammatory changes in the eyes and skin; decreased in body weight gains; increases in MCV, MCH, monocyte ratio, and serum protein and uric acid; decreases in lymphocyte ratio and erythrocyte count, hematocrit, hemoglobin, albumin, A/G ratio, cholesterol (esterified, total and free), phospholipids, triglycerides, cholinesterase activity and creatinine; increases in relative liver and adrenal weights. Histopathological examinations revealed melanin deposits in superficial lymph nodes, increases in macrophage and plasma cell accumulation, and corneal atrophy accompanied by melanin deposits and capillary proliferation. A slight black-brown patch (melanin deposition) in the conjunctiva and skin was observed in the 0.1 and 0.5 mg/kg/day groups. No drug-related changes were observed in groups that received 0.02 and 0.004 mg/kg/day. All changes observed during the treatment period disappeared during recovery except for melanin deposits in the conjunctiva and superficial lymph nodes, corneal opacity, and a few hematological and blood chemistry parameters. In conclusion, the no-toxic dose in these 52-week studies was estimated to be 0.02 mg/kg/day.

Male fertility in rats treated with etretinate for 4 weeks.

The toxicity of Etretinate, a retinoid compound, on the male reproductive system was studied in male rats. The drug was administered for four weeks at the dose levels of 0 (control: Vehicle, Peanut oil), 5 and 25 mg/kg/day. The animals were then allowed to mate, and their male reproductive functions and organs were examined in detail. No significant changes due to toxicity were observed in male reproductive functions and organs in the 5 mg/kg/day group after the 4-week treatment. In contrast, males in the 25 mg/kg/day group showed drug-related changes in their reproductive performance (decrease of mating ability and fertility rate), testosterone blood level, sperm head counts, sperm viability and number in the caudal epididymis, organ weight and in the histopathology of their reproductive organs (atrophy of seminiferous tubules, necrosis of spermatocytes and spermatids, vacuolation of nuclei of spermatocytes and spermatids). Even though Etretinate belong to the retinoid group of compounds, the changes seen in the 25 mg/kg/day group were almost the same as those observed in Vitamin A-deficient animals. In conclusion, there is a correlation between changes due to toxicity observed for parameters of male fertility and for histopathological evaluation of the testis of rats that receiving high dose, treatment with Etretinate for 4 weeks.

Isometric Measurement of Hamstrings and Quadriceps Strength in Multiple Sclerosis Patients: Sensitivity and Variability

The use of mechanized testing of quadriceps and hamstrings strength in isometric contraction in multiple sclerosis patients has not been previously reported. To determine the utility of such testing in clinical trials, two studies were carried out. First, to assess variability both within a testing session and between testing sessions, twenty-four MS patients with leg weakness that had been stable for at least two months were evaluated every eight weeks over a sixteen-week period. Quadriceps and hamstrings strength were measured in isometric contraction in triplicate at each testing session. The intra-class correlation coefficient for the mean strength determinations done every eight weeks for sixteen weeks was 0.99 and the coefficients of variation were 7.81 ± 6.97% for hamstrings and 5.97 ± 4.03% for quadriceps. Only four series of determinations out of eighty-six had coefficients of variation greater than 20%. In the second study, patients undergoing symptomatic treatment with an experimental drug, 4-aminopyridine, were tested to determine whether treatment-related changes were seen, and these changes were compared with the results of conventional manual muscle strength testing. Isometric test results appeared to be more sensitive to drug-related changes than manual motor testing. These results suggest that quantitative isometric strength testing may be useful in clinical trials of MS patients. Key Words: Isometric testing—Multiple sclerosis—Leg strength.

Effects of pantoprazole on endocrine function in healthy male volunteers

In a randomized, double-blind, two-period crossover study, pantoprazole 40 mg or placebo were given orally to 12 male volunteers for 2 weeks each. There was a wash-out period of at least 1 week between the two treatment periods. The effects of pantoprazole or placebo on cortisol and testosterone (primary criteria), and tri-iodothyronine, thyroxine, thyroid-stimulating hormone, thyronine-binding protein, parathyroid hormone, insulin, glucagon, renin, aldosterone, follicle-stimulating hormone, luteotrophic hormone, prolactin and somatotrophic hormone were compared. In addition, intragastric 24-h pH, 24-h H(+)-activity, and volume of nocturnal gastric juice were determined by gastric aspiration technique. Pantoprazole did not influence plasma levels of testosterone, circadian cortisol concentrations or plasma cortisol levels after exogenous adrenocorticotropic hormone stimulation, as compared to placebo (P > 0.05, Koch's test). Furthermore, there were no clinically relevant changes with any of the other endocrine parameters. Pantoprazole significantly increased the median 24-h pH (group median 4.3 vs. 1.8; P < 0.001) and decreased 24-h H(+)-activity (4.0 vs. 22.6 mmol/L; P < 0.001). The volume of nocturnal gastric juice did not significantly differ between the two treatments. Pantoprazole was well tolerated and the frequency of adverse events was similar to placebo. No drug-related changes in laboratory values were observed. Pantoprazole did not influence endocrine function in healthy male volunteers during short-term treatment.

Subchronic toxicity of pentostatin in Wistar rats.

Pentostatin, an adenosine deaminase inhibitor, has been approved for the treatment of refractory hairy cell leukemia. In a preclinical toxicity study, Wistar rats were administered 0, 1, 10, 25, and 50 mg/kg (0, 6, 60, 150, and 300 mg/m2, respectively) pentostatin intravenously once a week for 26 wk (1.5-75-fold above the therapeutic dose in humans). Lymphoplasmacytic thyroiditis was present in 20% of females given 25 mg/kg and in 20 and 47% of males and females given 50 mg/kg, respectively. Thyroiditis was still present 4 wk following drug withdrawal. Thyroiditis was characterized by glandular enlargement, follicular epithelial hyperplasia and degeneration, colloid depletion, and interstitial infiltrates of lymphocytes and plasma cells. Drug-related changes in other tissues included lymphoid depletion of T-cell regions of thymus, spleen, and lymph nodes; bronchiolization of alveolar ducts with accumulation of mucus and foamy macrophages; testicular atrophy with sperm granulomas; dermoepidermal lymphocytic infiltrates with ulceration and alopecia; and hepatocytomegaly.

Placebo response in antidepressant drug trials

SummaryResponse patterns derived from dichotomized (0/1) weekly CGI ratings conducted in antidepressant drug trials (Quitkin et al, 1984) were compared with those found in the pooled data from several randomized double-blind trials comparing the relative efficacy and tolerability low-dose flupenthixol im with that of three trieyclics (amitriptyline sr, imipramine, doxepine). Using the configurational frequency analysis (Krauth and Lienert, 1973), the postulated patterns could be rediscovered in our data apart from “early onset persistent patterns” which were less frequent in Quitkin et al's (1984) drug data. However, apart from this finding no “typical” patterns in terms of drug- or placebo-dependent response patterns could be detected in either the flupenthixol or Quitkin et al's (1984) data. It is concluded that there is little empirical evidence for the assumption of placebo- or drug related change- or response patterns. Moreover, theoretical aspects do not support the usefulness of such concepts.

13-week oral toxicity study of lactitol (NS-4) in dogs followed by 4-week recovery test

13-week repeated dose toxicity studies were conducted on lactitol, a hepatic encephalopathy drug. In the experiment I, male and female dogs were orally treated with lactitol at doses of 0, 1.0, 2.5 and 6.25 g/kg/day for 13 weeks, followed by 4 weeks recovery period. In the experiment II, male and female dogs were orally treated with lactitol at doses of 0, 0.25, 0.50 and 1.0 g/kg/day for 13 weeks in order to require the no-toxic dose. 1. Soft stool and diarrhea were observed at the 0.50 g/kg group and above, and vomiting was observed at the 1.0 g/kg group and above. Increased water consumption was observed at the 6.25 g/kg group. No deaths occurred at all groups. 2. In urinalysis, increased urine volume was observed at the 6.25 g/kg group. 3. Blood chemistry showed decreased BUN at the 6.25 g/kg group. 4. There were no drug-related changes in body weight, food consumption, ophthalmological examination, electrocardiography, hematology and pathology. 5. At the end of the recovery period, all these changes observed at the end of the administration period were disappeared. Based on these results, it was considered that the no-toxic dose of lactitol is 0.25 g/kg/day.

Topical Effect of Intravesical Oxybutynin

Intravesical oxybutynin was instilled into rat bladders in graded doses by repeated catheterization to study the local bladder effects of drug concentration and incidental urinary infection. On the thirteenth day, after 5 doses, bladders were recovered for measurement and histological study. In the highest dose group, systemic absorption from the bladder caused weight loss and cachexia. However, in no group was there any clear evidence of drug-related mucosal or bladder wall change. Instead, the two high dose groups seemed somehow protected from the combined adverse effects of catheterization and infection.

A 4-week subcutaneous toxicity study of recombinant human interferon alpha A (LBD-007) in Sprague-Dawley rats.

Recombinant human interferon alpha A (code name: LBD-007) was subcutaneously administered to both sexes of Sprague-Dawley rats at the doses of 0, 6, 12 and 24 x 10(6) IU/kg of body weight five days per week for 4 weeks to evaluate the subchronic toxicity. 20 to 50% of rats except the male control group showed minimal to mild, focal to multifocal renal mineralization. Whether renal mineralization is related to the test substance is not elucidated. Male rats dosed at 24 x 10(6) IU/kg showed the decrease of the absolute kidney weights and the increase of the brain relative weights. Female rats dosed at 24 x 10(6) IU/kg showed the increase of the absolute and relative ovary weights, and the decreases of specific gravity, bilirubin and urobilinogen in urine. However, no drug-related changes were noted in clinical findings, body weights, food consumption, water consumption, hematology, blood clinical chemistry and necropsy findings. Based on the results it is concluded that the estimated subcutaneous non-toxic dose of the recombinant human interferon alpha A (LBD-007) in rats is (6 approximately 12) x 10(6) IU/kg.

A 6-month subcutaneous toxicity study of recombinant human interferon alpha A (LBD-007) in Sprague-Dawley rats.

Recombinant human interferon alpha A (code name: LBD-007) was subcutaneously administered to both sexes of Sprague-Dawley rats at the doses of 0, 3, 6 and 12 x 10(6) IU/kg of body weight six days per week for 6 months to evaluate the chronic toxicity. Male rats dosed at 12 x 10(6) IU/kg for 26 weeks showed a decrease of ketone body in the urine, and female rats dosed at 12 x 10(6) IU/kg for 26 weeks showed a decrease of serum alkaline phosphatase. Microscopic changes with remarkable incidence were nephropathy, renal mineralization and ultimobranchial cysts of the thyroid gland in all groups of both sexes of rats. These changes were not considered to be drug-related toxicity because they appeared to be minimal, occasionally mild in severity and did not have dose-dependency as well as clinical significance. In general, no drug-related change was noted in clinical findings, body weights, food consumption, water consumption, hematology, organ weights and necropsy findings. Based on the results, it is concluded that the estimated subcutaneous non-toxic dose of the recombinant human interferon alpha A (LBD-007) in rats would be 6 x 10(6) IU/kg.

Acetyl- l-carnitine: Behavioral, electrophysiological, and neurochemical effects

—Aged rats were chronically administered acetyl- l-carnitine (AC) for 10 months. During this period they were tested on learning and sensorimotor tasks and were then subsequently tested electrophysiologically to assess induction and decay rates of long-term synaptic enhancement (LTE) in the hippocampus. Four groups were tested: young controls (4 mo-con), middle-aged controls (16 mo-con), old controls (24 mo-con), and old AC-treated rats (24 mo-AC). After completion of electrophysiological testing, each rat was sacrificed and investigated for age- or drug-related changes in three neurotransmitter markers; including, NMDA-sensitive glutamate receptors, high affinity choline uptake, and adenosine receptor number in the neocortex, hippocampus or caudate nucleus. Aging impaired spatial learning and there was a robust positive correlation between NMDA receptors in the hippocampus and acquisition of the spatial learning task. Induction of hippocampal LTE was reduced in 24 mo-AC rats and NMDA receptor number and high-affinity choline uptake in the frontal cortex was increased. Several suggestions are offered to explain the action of AC on these neurobiological parameters in old rats.

Orally administered cefpodoxime proxetil for treatment of uncomplicated gonococcal urethritis in males: a dose-response study

An open-label, dose-response study of cefpodoxime proxetil (CPD), an expanded-spectrum cephalosporin, was conducted with 58 males with uncomplicated Neisseria gonorrhoeae infections with single doses of 600, 400, 200, 100, or 50 mg of CPD administered orally by tablet. CPD eradicated N. gonorrhoeae in all 50 evaluable patients (10 per group) at all doses studied. Eight of the isolates eradicated were beta-lactamase-producing organisms. Two patients reported three side effects, nausea, vomiting, and diarrhea, which were mild and resolved without intervention or sequelae. There were no clinically remarkable drug-related changes in vital signs or clinical laboratory assays. Results show that single oral doses of CPD are an effective and well-tolerated treatment for uncomplicated N. gonorrhoeae infection in males at doses as low as 50 mg.

Acetylcholine modulates averaged sensory evoked responses and perforant path evoked field potentials in the rat dentate gyrus

The effect of localized application of acetylcholine (ACh) on well chacracterized components of sensory evoked and electrically induced potentials in the dentate gyrus was investigated in rats while performing a tone discrimination task. Local pressure application of ACh to the granule cell layer of the dentate gyrus through the recording pipette increased the amoplitude of perforant path evoked population spikes without changing the amplitude of the field EPSP. When the pipette was relocated to the outer molecular layer of the dentate (OM), ACh application decreased the amplitude of the perforant path field EPSP. Two major components of the averaged auditory evoked potential (AEP) recorded during criterion performance of the discrimination task were significantly changed by dendritic application of ACh. The N 1 component of the OM AEP which has been shown to reflect perforant path synaptic activity decreased in amplitude while the N 2 component wich represent activity from septal connections, was significantly increased. These effects were not due to pressure ejection nor drug related changes in behavioral performance of the task. The results suggest that ACh may act to differentially modulate the synaptic excitability of dentate granule cells, allowing them to acquire responses to sensory stimulation during establishment and maintenance of discrimination learning.

Comparison of error patterns produced by scopolamine and MK-801 on repeated acquisition and transition baselines.

An understanding of the differential role of cholinergic and glutaminergic systems may be limited by the failure to move the analysis of learning impairments beyond an assessment of changes in overall accuracy. This paper reports the results of two studies in which the effects in rats of scopolamine (0.5-3.0 mg/kg IP), a cholinergic antagonist, and MK-801 (0.05-0.3 mg/kg IP), an NMDA-receptor antagonist, were compared in two different repeated learning procedures and the nature of the underlying error patterns produced by each was evaluated. The first study examined drug effects upon a repeated sequence acquisition procedure and found that while both drugs decreased overall accuracy in a dose-dependent manner, the predominant error pattern varied significantly with drug; scopolamine primarily produced skipping errors within the sequence, whereas MK-801 more prominently increased perseveration on the first and second members of the sequence. In the second study, which used a repeated transition procedure, both drugs again significantly decreased overall accuracy in a dose-dependent manner, but no consistent differences in error patterning produced by the drugs were observed. Thus, while both cholinergic and NMDA systems play a role in learning, the behavioral processes underlying the changes in overall accuracy may differ, as indicated by the differential patterns of errors produced by scopolamine and MK-801 in the repeated acquisition baseline. Furthermore, the observed differences in the underlying behavioral processes of scopolamine and MK-801 in the repeated acquisition but not on the repeated transition procedure suggest that each of the two drugs may affect more than one of the variables controlling behavior, with the relative impact of drug-related changes in controlling variables depending upon the operative contingencies of the learning task.

A 52-week oral chronic toxicity study of 6-amidino-2-naphthyl 4-[(4,5-dihydro-1H-imidazol-2-yl)amino] benzoate dimethanesulfonate (FUT-187) in rats with a recovery period of 5 weeks.

The chronic toxicity of FUT-187, a synthetic protease inhibitor, was investigated in Sprague-Dawley rats. FUT-187 was given orally to the rats at doses of 0.4, 2, 10, 50 and 250 mg/kg/day for 52 weeks. The drug was then withdrawn for 5 weeks. The results are summarized as follows: There were no deaths or toxic signs caused by the drug throughout the experimental period. There were no drug-related changes in food consumption, ophthalmological examination, hematology or blood chemistry. Slight suppression of growth was observed in males in the 250 mg/kg group. This change was reversed on withdrawal of the drug. Drug crystals were observed in the urinary sediments of both sexes in the 250 mg/kg group, but this change disappeared on withdrawal of the drug. Gross pathological examination revealed the following changes: enlargement and nodule formation in the pancreas in both sexes given more than 10 mg/kg of the drug; dark red spots in the glandular stomach in males in the 250 mg/kg group; thickening of the small intestinal walls in both sexes given more than 50 mg/kg. Of these organs, no changes were observed in the stomach and small intestine at the end of the recovery period. Increased pancreas weight was observed in both sexes given more than 50 mg/kg of the drug. Examination at the end of the recovery period suggested reversibility, showing a lesser degree of change. Histopathological examination revealed the following changes in the pancreatic acinar cells: acidophilic foci and nodules in both sexes given more than 10 mg/kg of the drug; adenoma in one male in the 250 mg/kg group; increased zymogen granules in both sexes given more than 50 mg/kg of drug; fine vacuolization in females in the 250 mg/kg group. At the end of the recovery period, increased zymogen granules and fine vacuolization of the acinar cells were not found. Furthermore, erosion or healed erosion in the glandular stomach, duodenum and jejunum was observed in a few males or females in the 250 mg/kg group, but those changes disappeared after the recovery period. In the liver, altered cell foci was observed more frequently in males in the 250 mg/kg group than the other groups, but this change also disappeared after the recovery period. In addition, brown pigmentation in the proximal renal tubules of the kidney was observed in both sexes in the 250 mg/kg group, but lesions observed in the examination after the recovery period were less noticeable than in the examination at the end of the administration period.

PENGOBATAN PENDERITA MALARIA FALSIPARUM TANPA KOMPLIKASI DENGAN MEFLOKUIN DI DAERAH RESISTEN KLOROKUIN

Treatment with mefloquine of uncomplicated falciparum malaria patients was undertaken in ITCI Hospital, Balikpapan, East Kalimantan, Indonesia in 1991. This study was conducted to assess the efficacy and safety of mefloquine, and to assess in vitro sensitivity of P. falciparum to other antimalarials currently in use. A total of 16 falciparum malaria patients who had been selected according to WHO criteria for the drug sensitivity test were treated with 750 mg mefloquine single dose orally. All patients were hospitalized for 3-5 days and followed up on day 7, 14, 21 and 28. Clinical and parasitological examinations were carried out during the study, haematological and biochemical examinations were also performed before drug administration and when the patient was discharged from the hospital. The main presenting symptoms were chills, headache and fever. Cure rate was 100% with the mean fever clearance time and parasite clearance time was 9.3 ±_ 2.4 hours and 47.1 +_ 3.7 hours respectively. No significant drug-related changes were noted in hematological or biochemical parameters. Only nausea was observed as a side effect of mefloquine which was mild and disappeared without treatment. ITCI Hospital area is a highly chloroquine resistant area (90,9%) and also as a multidrug resistant area (50%). This study shows that mefloquine is effective and safe for the treatment of uncomplicated falcipamm malaria resistant to chloroquine as well as for multidrug resistant cases.

A 13-week dermal toxicity study of prednisolone farnesylate (PNF) gel in rats with a recovery period of 5 weeks

The toxicity of Prednisolone farnesylate (PNF) gel, a synthetic glucocorticoid, was investigated in the Sprague-Dawley rat. PNF gel was administered dermally to the rats at doses of 0.25, 1, 4 and 16 mg/kg/day for 13 weeks, then the drug was withdrawn for 5 weeks to evaluate the reversibility. In addition, 10 mg/kg/day prednisolone gel (PN gel), which is approximate to 16 mg/kg/day PNF gel in prednisolone molarity, was also administered to the rats for comparison. The results are summarized as follows: 1. In the PNF gel 16 mg/kg/day group, temporary erythema at the application site, retarded body weight gains, a decrease in the white blood cell count and lymphocyte ratio with an increase in the segmented neutrophil ratio, an elevation of serum AIP activity were observed. The pathological examinations revealed atrophy of the adrenal glands, lymphatic organs and skin. In addition, histopathological lesions were also found in the liver, pancreatic islets, bone, bone marrow and mammary glands. 2. In the PNF gel 4 mg/kg/day group, retarded body weight gains were observed, and histopathological lesions were noted in the adrenal glands, lymphatic organs, skin at the application site, liver and bone marrows. 3. In the groups that received less than 1 mg/kg/day of PNF gel, there were no toxic signs induced by the drug. 4. In the PN gel 10 mg/kg/day group, drug-related changes were almost similar to those of the PNF gel group, but the severity of the lesions was stronger than in the PNF gel group. 5. After the 5-week recovery period, the above changes almost completely disappeared and so it was demonstrated that the changes were reversible. 6. Based on these results, it was concluded that the overt toxic dose of PNF gel was 4 mg/kg/day and the non-toxic dose was 1 mg/kg/day in the present study.

Long Term Toxicity Studies in Rats and Dogs with the Antiarrhythmic Agent Pirmenol Hydrochloride

Pirmenol HCl, a new antiarrhythmic, was studied for toxicity in rats and dogs following oral administration for 52 consecutive weeks. Dogs were given 5, 10 and 15 mg/kg twice daily whereas rats received 25, 50 and 100 mg/kg/day. Transient responses in dogs such as dry oral mucosa represented pharmacological reactions. Rats showed weight gain suppression and lowered food consumption; serum glucose was slightly reduced at 50 and 100 mg/kg. There were no overt drug-related changes in other parameters indicating that pirmenol HCl does not have detrimental effects on rats and dogs following long term administration.

Effect of repeated oral administration of BY 1023/SK&amp;F 96022 – a new substituted benzimidazole derivative – on pentagastrin‐stimulated gastric acid secretion and pharmacokinetics in man

Pentagastrin stimulated gastric secretion was measured in 12 healthy male subjects after repeated once daily oral administration of 20 and 40 mg BY 1023/SK&F 96022--a new substituted benzimidazole derivative. Twenty milligrams inhibited acid output compared with placebo by 24% (2.5-3.5 h) and 26% (24.5-25.5 h) after the first oral intake. Inhibition increased to 56% and 50%, respectively, after the seventh oral dose. Forty milligrams inhibited acid output by a mean of 51% (2.5 to 3.5 h) and 52% (24.5-25.5) after the first oral intake. After the seventh dose mean inhibition rose to 85% and 66%, respectively. The drug was well tolerated, no drug-related changes in clinical laboratory, ECG, heart rate and blood pressure were observed. Fasting gastrin serum concentrations tended to increase with both doses, the mean values being within the normal range. AUC, Cmax and t1/2 of the drug after repeated oral intake were not significantly different when compared with a single dose at either 20 mg or 40 mg.

Laboratory Study of Drug-Related Performance Changes

Performance decrements associated with therapeutic drugs may increase the risk of many common activities that require intact skills. However, accident data that define such risks are difficult to obtain, and the assessment of skill decrements often must be based on data obtained from the laboratory study of drug effects. The validity and reliability of conclusions drawn from laboratory data are a function of experiment design and measurement methods. Critical issues include the assumptions, rationale, and hypotheses underlying laboratory measurement of skills performance. Drug doses and dosing regimens, subject characteristics, and response measures are key variables that limit data interpretation. The design of reported experiments, including the selection of a battery of laboratory tests, reveals the underlying issues, and data from the experiments demonstrate both valid conclusions and constraints on interpretation.