PubMed Health⌕ Search

Biomedical subjects

P Seideman

Publications and source records attributed to P Seideman.

At least 37 records · Page 2Linked to original sources
PubMed1991

Lack of effect of paracetamol on the pharmacokinetics of indomethacin and paracetamol in humans.

Paracetamol is an analgetic drug with additive effect if combined with indomethacin. In rat experiments, paracetamol has been shown to be gastro-protective, and in animal experiments, indomethacin blood levels decreased during combined treatment with paracetamol. The kinetic effect of paracetamol on indomethacin has been investigated in ten healthy volunteers. The mean area under the indomethacin plasma concentration curve AUC 0-alpha was 10.4 +/- 4.21 micrograms/mL x hr and did not change during combined paracetamol treatment (11.0 +/- 3.24 micrograms/mL x hr NS). Paracetamol levels were unchanged. In this study, no evidence was found that paracetamol can alter the pharmacokinetics of indomethacin in humans.

Acetaminophen↗
PubMed1991

Trace analysis of methotrexate and 7-hydroxymethotrexate in human plasma and urine by a novel high-performance liquid chromatographic method.

A new high-performance liquid chromatographic method for the quantitative determination of methotrexate (MTX) and its metabolite 7-hydroxymethotrexate (7-OHMTX) in blood plasma and urine was developed. The method utilized a solid-phase extraction procedure (Certify II cartridges) for the simultaneous isolation of MTX and 7-OHMTX. Chromatographic separation was achieved using a C18 reversed-phase column with isocratic elution. The eluent was irradiated with UV light of 254 nm, which converted MTX and 7-OHMTX by photolytic oxidation to fluorescent products. The limits of detection of MTX and 7-OHMTX in plasma were approximately 0.2 and 1 nmol/L, respectively. The intraday variability in the quantitation of MTX and 7-OHMTX was less than 8% down to 1 nmol/L and 4.6 nmol/L, respectively. Both MTX and 7-OHMTX could be detected in plasma from a patient being treated for rheumatoid arthritis 1 week after the last dose (10 mg orally).

Chromatography, High Pressure Liquid↗
PubMed1991

Cerebral blood flow and indomethacin drug levels in subjects with and without central nervous side effects.

1. Central nervous system (CNS) side effects are observed during treatment with all nonsteroidal anti-inflammatory drugs (NSAIDs) but their effects are more common during treatment with indomethacin. 2. The aim of the study was to elucidate the mechanism of the CNS related side effects of indomethacin. Two groups were obtained, one with (n = 11), and one without (n = 7), CNS symptoms. Cerebral blood flow was measured in these groups with Doppler equipment, indomethacin levels with h.p.l.c. and CNS symptoms graded on a VAS scale. 3. Blood flow was reduced by 18-30% and was most marked 60 min after dose and did not differ between the two groups. The maximum CNS effect coincided with indomethacin peak levels 60-70 min after dose. These results could implicate that CNS symptoms may be related to indomethacin levels in sensitive patients.

Brain↗
PubMed1991

NSAIDs, musculoskeletal disorders and gastrointestinal adverse effects.

Paracetamol should be considered as first line treatment for the common painful musculoskeletal disorders, especially osteoarthrosis. NSAIDs, which are beneficial should this fail and inflammation be present, should be prescribed in the lowest dose for the shortest possible time.

Acetaminophen↗
PubMed1989

Influence of chronic diflunisal treatment on the plasma levels, metabolism and excretion of indomethacin.

The single-dose pharmacokinetics of indomethacin following 100 mg rectally was measured in two groups of 8 healthy subjects before and after diflunisal 500 mg p.o. once daily, or 500 mg in the morning and 1000 mg in the evening, until steady state conditions were reached. A further group of 8 healthy subjects was given 50 mg indomethacin rectally before and after diflunisal 500 mg p.o. twice daily. High dose diflunisal (1500 mg/day) decreased the renal clearance of indomethacin from 21.9 to 1.8 ml/min (92%) and reduced the renal excretion of both unchanged (63%) and conjugated (82%) indomethacin. The apparent total body clearance (0.12 l/h/kg), apparent volume of distribution (0.98 l/kg), and volume of distribution at steady state (0.80 l/kg) were decreased by 47%, 35% and 30%. The maximum plasma concentration (2.4 micrograms/ml) and total area under the curve (13.0 micrograms x h/ml) were increased by 40% and 119%, respectively. The terminal elimination half-life (5.7 h) and mean residence time (6.7 h) were slightly prolonged (7.0 h and 8.8 h) in the presence of diflunisal. The contribution of metabolism to the overall elimination of indomethacin was increased by only 2%. Similar results were obtained when the subjects were challenged with the low dose of diflunisal (500 mg/day), although the magnitude of the changes were smaller. The interaction between indomethacin and diflunisal may be due to competition both at the metabolic (conjugation) and the excretory (tubular secretion) levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

The effect of diclofenac sodium on renal function.

The effects of diclofenac sodium on the kidneys were studied during 4 1/2 hours in eight patients with normal renal function. Urinary output decreased within 10 min after the injection, and maximally by 80%. The renal plasma flow and the glomerular filtration rate initially diminished significantly, by 35%, but began to increase after only 2 hours. The dominant and persistent effect was reduction of free water clearance, with maximum fall from 5.9 to 0.08 ml/min after 2 1/2 hours. The long-lasting increased tubular reabsorption of water probably is important for the lowered intrapelvic pressure that is associated with good analgetic effect of diclofenac in ureteral colic.

Adult↗
PubMed1989

Computerized assessment of radiological changes of the hand in rheumatic diseases.

Evaluations of radiological changes in rheumatic diseases are subject to great inconsistency. In this study, digital image analysis is shown to be a promising tool in the evaluation of joint space narrowing. The repeatability of the measurements is shown to be better than that of manual methods and is also less dependent on the observer.

Aged↗
PubMed1989

Pharmacokinetic interactions of penicillamine in rheumatoid arthritis.

The pharmacokinetic effect of the combined treatment of penicillamine with indomethacin and chloroquine was investigated in patients with rheumatoid arthritis. The mean plasma penicillamine concentration increased by 26% during indomethacin and 34% during chloroquine treatment. This new pharmacokinetic interaction may have important clinical implications.

Adult↗
PubMed1988

Equianalgesic effects of paracetamol and indomethacin in rheumatoid arthritis.

The therapeutic and adverse effects of 2 weeks of treatment with high-dose indomethacin (150 mg/day) were compared with those of low-dose indomethacin (50 mg/day) combined with paracetamol (4 g/day) in a double-blind, double-dummy, cross-over study in 17 patients with active rheumatoid arthritis. Grip strength, Ritchie's index, joint circumference, joint pain, and patient's and physician's global assessments were estimated, and conventional laboratory parameters were followed. In addition, the time-concentration profiles of indomethacin and paracetamol were assessed during steady state. All patients had measurable plasma drug levels, indicating adequate compliance, and responders and nonresponders (five on each treatment) had equal drug levels, indicating that the variation in therapeutic efficacy was not secondary to pharmacokinetic differences. While there were fewer and milder side-effects during treatment with the drug combination, there was no difference in therapeutic efficacy. Hence, it appears that the main therapeutic profit of indomethacin in daily doses greater than 50 mg is enhanced analgesia. As such dosage involves pronounced side-effects, it seems more appropriate to employ the combination of 50 mg indomethacin and 4 g paracetamol, whereby similar analgesia can be obtained without an increase in side-effects.

Acetaminophen↗
PubMed1988

Effect of felodipine in refractory hypertension.

Felodipine (Plendil), a new drug, has been used in the treatment of five patients with refractory essential hypertension (WHO II-III). Their mean blood pressure at the last outpatient visit before the study was opened was 195 +/- 25/129 +/- 21 mmHg (mean +/- s.d.) (range 175-235/110-165 mmHg), despite treatment with combinations of diuretics, beta-blockers and vasodilators, including minoxidil and captopril. Felodipin is a dihydropyridine derivative, a calcium antagonist that exerts a relaxant effect on resistance vessels. The first period of the study consisted of a 5-day stay in hospital followed by 3 months during which observations were carried out at the Outpatients' Department. After the first days in hospital felodipine therapy was introduced at a dose of 25 mg three times daily, given together with diuretics, beta-blockers and, in one case, captopril. At 8.00 immediately before the first dose was given, the blood pressure was 178 +/- 19/118 +/- 19 mmHg (mean +/- s.d.); 2 h later it was 144 +/- 18/85 +/- 4 mmHg, at which level it remained throughout the rest of the study. At the 3-month follow-up the mean pressure (recorded at the Outpatients' Department) was 138 +/- 20/89 +/- 14 mmHg. Side-effects included headache, flushing, palpitations and ankle oedema (in two patients during the second part of the study); they were of a mild to moderate degree and did not interfere with the treatment. There was no evidence of general fluid retention, and the body weight remained constant.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Decreased plasma concentrations and clinical effects of alprenolol during combined treatment with pentobarbitone in hypertension.

The antihypertensive effect of alprenolol has been studied before, during and after additional pentobarbitone treatment. The combined alprenolol-pentobarbitone treatment significantly decreased alprenolol levels by 59% and 4-hydroxyalprenolol by 24%. The effect was significant after three doses and declined over 4-5 days after pentobarbitone withdrawal. The decreased alprenolol plasma levels were associated with increased pulse rate (6%), and systolic (8%) and diastolic (9%) blood pressure. The inhibition of exercise tachycardia by alprenolol was reduced by 18% at the end of pentobarbitone treatment compared to initial monotherapy with alprenolol. The interaction is probably clinically important in those patients with hypertension and angina pectoris that are treated with barbiturates and alprenolol.

Adult↗
PubMed1987

Additive renal effects of indomethacin and dipyridamole in man.

The effect of dipyridamole alone and in combination with indomethacin was studied in 11 water loaded rheumatic patients with normal kidney function. The adenosine uptake inhibitor dipyridamole and the prostaglandin synthesis inhibitor indomethacin decreased diuresis by 25-50% when given alone and by approximately 80% when combined. These effects were not associated with changes in renal PAH-clearance, but may be partially related to a fall in GFR. Sodium excretion was decreased in parallel with the fall in GFR. In addition, both indomethacin and dipyridamole reduced the free water clearance. Theophylline at therapeutic plasma levels reversed the reduction in GFR and transiently counteracted the inhibition of tubular water and sodium excretion induced by combined dipyridamole and indomethacin treatment. The results suggest that endogenous adenosine and prostaglandins are both involved in the control of renal function in man, and that drugs that affect these two autocoids may interact to cause adverse effects in man.

Adenosine↗
PubMed1987

Psoriatic arthritis treated with oral colchicine.

We investigated the use of colchicine in psoriatic arthritis to determine if we could confirm the good results obtained in an earlier, uncontrolled study. Twelve of 15 patients with psoriatic skin lesions and arthritis completed a 16-week placebo controlled double blind crossover study. A significant improvement was noted in grip strength, Ritchie's index, joint size, joint pain and overall therapeutic assessment. Psoriatic skin lesions were not improved by colchicine. The few side effects observed were related to gastrointestinal intolerance, which were usually controlled by temporarily reducing the dose of the drug. Our results indicate that 1.5 mg colchicine daily is an effective treatment for psoriatic arthritis.

Administration, Oral↗
PubMed1984

Short-term effects of felodipine, a new dihydropyridine, in hypertension.

Felodipine, a dihydropyridine, is a new vasodilating calcium antagonist which lowers blood pressure (BP) by selective action on vascular smooth muscle, especially in the resistance vessels. The effects on BP, heart rate (HR) and tolerance of different single oral doses of felodipine were studied in two series of hypertensive patients. When felodipine was given as single drug to 14 previously untreated hypertensives in a single-blind manner, BP was rapidly reduced by about 15% while HR increased by 25%. Felodipine given in a double-blind manner to eight patients on chronic beta-adrenoceptor blockade reduced BP by some 15-20% compared to placebo, while HR did not change. There was a significant correlation between the pre-treatment mean arterial BP (MAP) and the maximal relative change in MAP, i.e. the higher the initial BP the greater the reduction after felodipine. A significant correlation was also found between the plasma concentration of felodipine and the relative change in MAP. Felodipine was generally well tolerated. When given alone felodipine caused the side effects expected from a pure vasodilator, i.e. headache, flushing and palpitations. When given together with a beta-adrenoceptor blocker, the side effects were much less apparent.

Adult↗
PubMed1982

Alpha-receptor function changes after the first dose of prazosin.

The effect of oral prazosin on blood pressure and antagonism of phenylephrine-induce blood pressure increase was investigated in six healthy subjects during a dosing interval after the first dose and 3 days after the first dose of the drug. Prazosin lowered standing blood pressure more after the first dose than after the same dose 3 days later, despite similar plasma levels. Blood pressure decrease correlated with plasma prazosin levels during the elimination phase at the first dose, but not after 3 days of therapy. The phenylephrine log dose-response curves shifted to the right after prazosin, which indicates alpha-receptor antagonism of the drug. On day 4, the phenylephrine curve before prazosin dose shifted to the right of the pretreatment curve on day 1, despite very low prazosin plasma levels. On day 4 after after prazosin dosing the phenylephrine dose-response curves were shifted to the left of that on day 1. Our data indicated tolerance to prazosin effect on blood pressure and to phenylephrine agonism after 3 days dosing. Our data suggest that this might be due to desensitization of alpha-adrenoceptors with differential effects of agonists and antagonists.

Adult↗