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PubMed2006

The occurrence and removal of selected pharmaceutical compounds in a sewage treatment works utilising activated sludge treatment.

Pharmaceutical substances have been detected in sewage effluents as well as receiving waters in many parts of the world. In this study, the occurrence and removal of a number of drug compounds were studied within a large sewage treatment plant in the south of England. Samples were processed using solid phase extraction and analysed using gas chromatography-mass spectrometry (GC-MS). The results demonstrate that ibuprofen, paracetamol, salbutamol and mefenamic acid were present in both the influent and effluent of the works while propranolol-HCl was not found above the limit of quantification in any sample. Elimination rates were circa 90% for each compound but several hundred nanograms per litre were still present in the final effluent.

Acetaminophen↗
PubMed1989

Experimental renal papillary necrosis in the Syrian hamster.

These studies evaluate the susceptibility of the Syrian hamster to the induction of renal papillary lesions after exposure to 2-bromethylamine (2-BEA), mefenamic acid, indomethacin, acetaminophen and phenylbutazone. In most cases there were 25 animals per dose group. Papillary necrosis was produced by single or multiple ip doses of 75 mg 2-BEA/kg and above, and was present within 12 hr of administration of a dose of 500 mg/kg body weight. There were lesions in the renal papilla of hamsters 10 days after a single dose of 500 mg 2-BEA/kg. The severity of papillary lesions increased up to 4 days after exposure in hamsters given a single dose of either 250 or 500 mg 2-BEA/kg. The severity of papillary lesions did not increase with the number of doses in hamsters given multiple doses (2-5) of 100 mg 2-BEA/kg. Renal papillary necrosis was observed in about 40% of hamsters given 100, 200 or 400 mg mefenamic acid/kg. Only a few of the hamsters given indomethacin had renal papillary lesions and none of those given acetaminophen (up to 400 mg/kg) or phenylbutazone (up to 600 mg/kg) developed renal papillary lesions.

Acetaminophen↗
PubMed1998

Effect of elevated viscosity in the upper gastrointestinal tract on drug absorption in dogs.

The objectives of these studies were, first, to determine the effect of elevated luminal viscosity on the gastrointestinal absorption of four model drugs and, second, to identify the key processes influencing drug absorption under elevated viscosity conditions. Studies were conducted in vitro and in healthy female mongrel dogs under fasting conditions. In the canine model, both the rate and extent of paracetamol and hydrochlorothiazide absorption were significantly decreased by the coadministration of 15 g guar gum dissolved in 500 ml normal saline. In the case of cimetidine, the rate but not extent of absorption was decreased. Owing to the high variability in the data, no statistically based conclusion could be drawn about the effects of coadministered guar gum on the oral absorption of the poorly soluble mefenamic acid. Based on the in vitro data, it appears that substantial reductions in the dissolution rate of paracetamol, hydrochlorothiazide and cimetidine account for the effects observed in vivo. It is concluded that the effect of an elevation in the intraluminal viscosity on drug absorption is greatest for highly soluble drugs, and results from a combination of a decrease in dissolution rate and gastric emptying rate.

Acetaminophen↗
PubMed1984

Mechanism of the biphasic arteriolar response to angiotensin II.

Male Sprague-Dawley rats (140-180 g) were anesthetized with alpha-chloralose and urethan. The cremaster muscle with intact blood supply and neural innervation was suspended in a tissue bath containing a modified Krebs solution. With the use of television microscopy the luminal diameters of third-order arterioles (14-32 micron) were measured before and after adding angiotensin II (ANG II, bath concn 10(-6) M). The arterioles responded to ANG II with an initial, transient constriction followed by a more prolonged dilation to a diameter larger than the control diameter. Pretreating the muscle with [Sar1, Ile8]ANG II significantly attenuated both the arteriolar constriction and subsequent dilation induced by ANG II. Treatment of the cremaster muscle with mefenamic acid or indomethacin, inhibitors of prostaglandin synthesis, produced a significant reduction in the diameter of the arterioles and abolished the dilator phase of the arteriolar response to ANG II without preventing the ANG II-induced constriction. These results demonstrate that within the intact microcirculation, ANG II produces both an arteriolar constriction and a dilation that are mediated by specific ANG II receptors. The ANG II-induced dilation of the arterioles appears to be caused by increased prostaglandin synthesis and release.

Angiotensin II↗
PubMed1975

Mode of action of antirheumatic drugs on the cyclic 3',5'-AMP regulated glycosaminoglycan secretion in fibroblasts.

The effect non-steroidal anti-inflammatory drugs on formation and release of glycosaminoglycans (GAG) and cyclic 3',5'-AMP levels was studied in embryonic mouse fibroblasts. The results were compared and correlated with the action of these drugs on cyclic 3',5'-AMP-dependent as well as independent protein kinase obtained from bovine diaphragm. 1. Phenylbutazone dose-dependently decreased cyclic 3',5'-AMP levels and GAG secretion both in unstimulated and PGE1 stimulated cells. 2. Indometacin decreased cyclic 3',5'-AMP levels and GAG secretion only in cells with elevated cyclic 3',5'-AMP levels after stimulation by PGE1. 3. Sodium salicylate decreased cyclic 3',5'-AMP levels in the presence and absence of PGE1. However, GAG secretion was reduced only in cells with elevated cyclic 3',5'-AMP levels, since the drug activated cyclic 3',5'-AMP-independent protein kinase activity, thus presumably precluding changes in GAG formation at low levels of cyclic 3',5'-AMP. 4. Mefenamic acid decreased cyclic 3',5'-AMP levels in cells stimulated by PGE1, whereas GAG secretion was increased both in the absence and presence of PGE1. This increase in GAG secretion was closely correlated to an enhanced cyclic 3',5'-AMP-dependent and independent protein kinase activity. The results indicate that non-steroidal anti-inflammatory drugs may exert their effects on GAG formation by interfering with cyclic 3',-5'-AMP formation or function.

Animals↗
PubMed1994

Effects of patent ductus arteriosus on left ventricular output and organ blood flows in preterm infants with respiratory distress syndrome treated with surfactant.

Thirty preterm infants (birth weight < 1500 gm) treated with Surfactant TA for the respiratory distress syndrome, who had no complicating clinical problems other than ductal patency, were studied by serial Doppler flow examinations to determine the effects of early left-to-right shunt through the patent ductus arteriosus on the left ventricular output and organ blood flows. Doppler flow variables in 15 infants with a hemodynamically significant patent ductus arteriosus (hsPDA) were compared with those in 15 subjects without hsPDA matched for age, body weight, and gestational age. Infants with hsPDA had significantly higher left ventricular output and significantly lower blood flow volume in the abdominal aorta, and lower temporal mean blood flow velocities, with concomitant increases in the relative vascular resistance in the celiac artery, superior mesenteric artery, and renal artery. Pulsatility indexes of these vessels and the anterior cerebral artery were significantly higher in the hsPDA group, but the temporal mean blood flow velocities in the anterior cerebral artery and its vascular resistance were not significantly different between the two groups. After closure of the patent ductus arterious was achieved with mefenamic acid therapy, alterations in Doppler flow variables in the hsPDA group reverted to the levels seen in the group without hsPDA. These results suggest that despite large left-to-right ductal shunting, the heart of the preterm infant is capable of mounting a compensatory increase of cardiac output sufficient to maintain unchanged cerebral blood flow, but is unable to maintain postductal organ blood flows because of decreased perfusion pressure (ductal steal) and localized increase in vascular resistance.

Blood Flow Velocity↗
PubMed1997

The role of the IsK protein in the specific pharmacological properties of the IKs channel complex.

IKs channels are composed of IsK and KvLQT1 subunits and underly the slowly activating, voltage-dependent IKs conductance in heart. Although it appears clear that the IsK protein affects both the biophysical properties and regulation of IKs channels, its role in channel pharmacology is unclear. In the present study we demonstrate that KvLQT1 homopolymeric K+ channels are inhibited by the IKs blockers 293B, azimilide and 17-beta-oestradiol. However, IKs channels induced by the coexpression of IsK and KvLQT1 subunits have a 6-100 fold higher affinity for these blockers. Moreover, the IKs activators mefenamic acid and DIDS had little effect on KvLQT1 homopolymeric channels, although they dramatically enhanced steady-state currents through heteropolymeric IKs channels by arresting them in an open state. In summary, the IsK protein modulates the effects of both blockers and activators of IKs channels. This finding is important for the action and specificity of these drugs as IsK protein expression in heart and other tissues is regulated during development and by hormones.

Animals↗
PubMed1975

The antagonism by anti-inflammatory analgesics of prostaglandin f 2 alpha-induced contractions of human and rabbit myometrium in vitro.

The anti-inflammatory analgesic drugs, aspirin, indomethacin, phenylbutazone, mefenamic acid ibuprofen and flurbiprofen are shown to inhibit in a dose-dependent manner the force of contraction of isolated human pregnant myometrial strips which have been stimulated to contract by adding prostaglandin (PG) F2alpha to the tissue bath. These drugs and also flufenamic acid and salicin show a similar antagonism of the action of PGF2alpha with isolated rabbit non-pregnant myometrium. The ratio of the inhibitory concentration in vitro to the maximum plasma level after a normal dose in vivo suggests that phenylbutazone and possibly ibuprofen may be capable of inhibiting human uterine contractions in vivo. Patients who were treated with aspirin during induction of abortion using PGF2alpha during the second trimester of pregnancy showed no significant change in the induction-abortion interval compared with patients not taking aspirin.

Abortion, Induced↗
PubMed1991

Meclofenamate inhibits prostaglandin E binding and adenylyl cyclase activation in human myometrium.

The effect of sodium meclofenamate on the binding of [3H]prostaglandin E2 [( 3H]PGE2) to membranes from human myometrium was investigated. Meclofenamate inhibited the binding of [3H]PGE2 to high-affinity (dissociation constant 1.5 nmol/l) sites in a reversible dose-dependent manner (inhibition constant 11 mumol/l). The mechanism of inhibition was mainly competitive, but at high doses of meclofenamate (greater than or equal to 100 mumol/l) there was loss of PGE receptor sites. Of several PG synthesis inhibitors tested, only meclofenamate and, to a lesser extent, mefenamic acid had a significant inhibitory effect. PGE2 stimulated cyclic AMP generation in slices of human myometrium and this was inhibited by meclofenamate in a dose-dependent manner (50% inhibition occurred at 9 mumol/l). Again, this effect was specific for meclofenamate and fitted a competitive mechanism at doses in the range 1-10 mumol/l and a non-competitive mechanism at higher doses. The data show that meclofenamate, in addition to its traditional role as a PG synthesis inhibitor, affects directly PGE receptor binding and activation.

Adenylyl Cyclases↗
PubMed1978

Asthma improved by nonsteroidal anti-inflammatory drugs.

A patient who claimed benefit from aspirin for her reversible bronchospasm was challenged orally in a placebo-controlled study with aspirin and other aspirin-like drugs. Specific airways conductance and spirometry were monitored for up to 150 minutes after oral challenge. Aspirin, mefenamic acid, and ibuprofen administration resulted in marked (45% to 80%) improvement in forced expiratory volume in 1 second (FEV1) compared to lactose placebo. Indomethacin, sodium salicylate, and tartrazine resulted in modest (15% to 25%) FEV1 improvement, while phenylbutazone produced a 25% decrease. These results are discussed here in terms of the ability of these drugs to inhibit the prostaglandin synthetase enzyme system. This case suggests that aspirin and other nonsteroidal anti-inflammatory drugs may be beneficial rather than harmful in some asthmatic patients.

Airway Resistance↗
PubMed1991

Attenuation of epileptogenesis by nonsteroidal anti-inflammatory drugs in the rat.

Subconvulsive doses (25 mg/kg) of pentylenetetrazol were administered at intervals of 4 days for 20 sessions, to induce kindling in conscious, free-moving rats, with chronically-implanted electrodes. This regimen induced an excitation of the CNS, which intensified over the 20 sessions. Periods of motor arrest, concurrent with bursts of electrocortical spike-wave activity, increased to clonic convulsions, concurrent with bursts of spike activity. Separate groups of rats were pretreated over the twenty sessions with nonsteroidal anti-inflammatory drugs (NSAIDs). Pretreatment with paracetamol produced a dose-related reduction in pentylenetetrazol-induced seizure activity. Pretreatment with 20 mg/kg mefenamic acid attenuated, while 60 mg/kg dose potentiated, the pentylenetetrazol-induced excitation. Pretreatment with 10 or 30 mg/kg ibuprofen had no significant effect, while 90 mg/kg was lethal, by itself, in 58% of the group. When all the groups received a single dose of pentylenetetrazol, three weeks after the twenty sessions, there were no significant differences between the groups in level of pentylenetetrazol-induced excitation, when compared to the control (saline-pretreated) group. This suggests that the effective NSAIDs had influenced the manifestation of, but not development of, epileptogenesis over the 20 sessions.

Animals↗
PubMed1979

Characteristics of histamine tachyphylaxis in canine tracheal smooth muscle.

In isolated canine tracheal smooth muscle, repeated administrations of histamine result in a rapid reduction in contractile response to about 15% of the initial contraction (tachyphylaxis). Development of this tachyphylaxis is specific inasmuch as: 1) it does not develop to acetylcholine (10(-6) M or 10(-4) M), or serotonin (10(-5) M; and 2) maximally developed histamine tachyphylaxis is not associated with a parallel reduction in response to acetylcholine. Pretreatment with propranolol (10(-5) M) or phentolamine (10(-4) M) does not prevent tachyphylaxis: however, pretreatment with atropine (10(-4) M) does prevent tachyphylaxis in about 50% of the animals tested. Tachyphylaxis to histamine can be reversed in a dose- and time-dependent fashion with prostaglandin synthesis inhibiting agents. The order of potency obtained with such compounds (indomethacin greater than mefenamic acid greater than oxyphenbutazone greater than acetylsalicylic acid) is consistent with potencies for inhibition of prostaglandin synthesis found in the literature. Also, in indomethacin pretreated strips in which tachyphylaxis to histamine was prevented, exogenous addition of PGE2 (1.42 x 10(1-) M to 2.84 x 10(-9) M) and PGA2 in a high concentration (2.9 x 10(-9) M) are capable of selectively reducing the response to histamine without an effect on acetylcholine-induced contractions. These data suggest that the mechanism of histamine tachyphylaxis in the canine tracheal smooth muscle preparation involves prostaglandin synthesis.

Acetylcholine↗
PubMed1994

Dirofilaria immitis: depression of endothelium-dependent relaxation of canine femoral artery seen in vivo does not persist in vitro.

In heartworm-infected dogs, circulating filarial factors appear to be responsible for the seasonal depression of endothelium-dependent responses seen in the in vivo femoral artery. The effect of heartworm infection on vascular responses of the femoral artery in vitro, when the vessel is not constantly exposed to circulating factors, is unknown. Experiments were designed to test the hypothesis that in vivo exposure to circulating filarial factors leads to changes in the magnitude and mechanism of endothelium-dependent relaxation that are demonstrable in vitro. Rings of femoral artery from heartworm-infected and noninfected control dogs were suspended in muscle baths, and dose-response relationships to endothelium-dependent (methacholine) and -independent (sodium nitroprusside) vasodilators were done. To determine the mechanism of relaxation, dose-response relationships were also done in the presence of an inhibitor of nitric oxide synthase (L-NAME), an inhibitor of guanylate cyclase (methylene blue), or an inhibitor of cyclooxygenase (mefenamic acid). Heartworm infection did not depress endothelium-dependent relaxation of the femoral artery in vitro. Furthermore, the mechanism of relaxation in heartworm and control femoral artery is identical. These data suggest that the effect of circulating filarial factors that alter the magnitude and mechanism of relaxation in systemic vessels in heartworm-infected dogs rapidly disappears in their absence. This results has important bearing on the dynamics of heartworm-induced pathophysiological changes during infection and could influence the nature and chronology of responses to therapy.

Animals↗
PubMed2003

[Variance of bioavailability of pharmaceutical preparations and analysis of factors affecting it].

Phenytoin (pulverized powder), mefenamic acid (capsule), and sulpiride (film-coated tablet) are currently available on the Japanese market. For absorption of these drugs from their pharmaceutical preparations, they must disintegrate and dissolve during passage through the gastrointestinal tract. The bioavailability of these drugs differ among different pharmaceutical preparations and even for the same preparation. This led to a review of the influence of the features of pharmaceutical preparations and the physicochemical properties of film coating materials as well as the physiologic factors affecting drug bioavailability. The influence of coadministered drugs and concomitant intake of beverages and food on the bioavailability of drugs from pharmaceutical preparations is also described.

Animals↗
PubMed1987

Effects of atrial natriuretic peptide on renal function and renin release in the isolated perfused rat kidney.

The effects of synthetic atrial natriuretic peptide (ANP) on the renal hemodynamics, glomerular filtration rate (GFR), fluid and electrolyte excretion and renin release were studied in the isolated perfused rat kidney (IPK). When 10(-9) mol of ANP was administered in 75 ml of perfusate, the renal vascular resistance (RVR) was transiently decreased for 3 to 5 min, thereafter increased for 30 min and then tended to return to the control level. ANP increased the GFR (0.55 +/- 0.08 to 0.71 +/- 0.07 ml/min), urine flow (UV) (0.018 +/- 0.002 to 0.194 +/- 0.028 ml/min), absolute Na excretion (UNaV) (1.83 +/- 0.03 to 17.93 +/- 2.71 microEq/min) and absolute K excretion (UKV) (0.67 +/- 0.13 to 2.33 +/- 0.18 microEq/min). The addition of indomethacin or mefenamic acid to the perfusate before the administration of ANP exerted no influence on any of the effects of ANP. Renin release was inhibited by approximately 50% compared to the ANP-free control group. With the administration of ANP, UV and UNaV reached a peak 15-20 min after the GFR reached a peak and remained elevated after the GFR fell below the control level. These findings suggest that 10(-9) mol of ANP causes natriuresis and renin suppression in the IPK, and that the natriuresis is prostaglandin-independent and cannot be explained only by an increase in GFR.

Animals↗
PubMed1992

Comparison of the safety and efficacy of a combination analgesic Myprodol and Ponstan in the treatment of dental pain.

A comparison of the efficacy of Myprodol, a combination analgesic (Ibuprofen, Paracetamol and Codeine phosphate) and Ponstan (Mefenamic acid) was undertaken in a randomised double blind trial of 52 patients who underwent surgical removal of impacted or unerupted teeth. Pain scores were measured for patients pre- and post operatively by means of a visual analogue scale and data was analysed using the BMPD package on the ISM main frame computer at the Medical Research Council. The results indicated that although Myprodol and Ponstan were equally adequate and well tolerated in the control of post operative dental pain, Myprodol exceeded Ponstan in duration of analgesia and in the degree of pain intensity control experienced by the patient.

Acetaminophen↗
PubMed2000

First-line management of menorrhagia: findings from a survey of general practitioners in Forth Valley.

This study was undertaken to determine local GPs' current management of menorrhagia, prior to the release of the Royal College of Obs tetricians and Gynaecologists' (RCOG) guideline on the initial management of menorrhagia. A postal questionnaire was sent to 204 GPs in the Forth Valley area. An 84% (n = 173) response rate was recorded. Responses were compared with RCOG guideline recommendations after its release. Fifty-two percent of respondents measured a full blood count and 56% performed a pelvic examination. Two thirds of GPs chose the recommended treatments (mefenamic acid or tranexamic acid) as their first or second choice of treatment in women not requiring contraception. One third chose cyclical progestogens. Only 10% of GPs selected an ineffective treatment (cyclical progestogens) as their first or second choice of treatment in women requiring contraception. This survey demonstrates that the majority of GPs are already prescribing the treatments recommended in the RCOG guidelines. There is a need for education amongst a minority to improve their practice. Half of the GPs reported compliance with the recommended investigations of full blood count and pelvic examination. The point at which these investigations are performed in the initial management of menorrhagia may need further discussion between primary and secondary care clinicians to clarify their purpose.

Data Collection↗
PubMed1991

Plasma exchange (PE) treatment in drug-induced toxic epidermal necrolysis (TEN).

Toxic epidermal necrolysis (TEN) or Lyell's syndrome is a rare fulminating skin disease notorious for its rapidly progressive course and high mortality rate. TEN is characterized by the sudden onset of epithelial necrosis of skin with frequently associated involvement of the gastrointestinal, genitourinary tract and bronchopulmonary linings. We describe the clinical course of five patients with severe drug-induced TEN, treated with PE. The suspected drugs were carbamazepine in one patient, paracetamol in one, a combination of paracetamol and mefenamic acid in one, allopurinol in one and ciprofloxacin in one. Three had a skin involvement affecting almost the entire surface of the body. In addition to the skin lesions, mouth, esophagus and lungs were also involved. Steroids proved ineffective. PE was carried out because of the rapid deterioration of the clinical picture. The mean number of PE sessions was 3.22 (range 1-5). Complete remission of the syndrome was achieved in four patients. One patient died due to septic shock. As so far there is no treatment of proven value for this condition, controlled trials should be set up in order to assess the value of PE in TEN.

Aged↗