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PubMed1984

Effect of acetazolamide on rat gastric mucosal protection and stimulated bicarbonate secretion with 16,16-dimethyl PGE2.

The effect of pretreatment with acetazolamide, a carbonic anhydrase inhibitor, was studied on the mucosal protection provided by and the gastric alkaline secretion stimulated by 16,16-dimethyl prostaglandin E2. Using a model employing a chamber of the rat whole stomach, 16,16-dimethyl prostaglandin E2 (1 microgram/ml) was found to significantly (p less than 0.05) increase the secretion of bicarbonate by 31.1 +/- 4.1 mu Eq/hr over basal values. This stimulated secretion was inhibited (to 18.0 +/- 2.2 mu Eq/hr) by pretreatment with acetazolamide (50 mg/kg body weight). In a separate series of experiments, the ability of this concentration of 16,16-dimethyl prostaglandin E2 to protect the rat stomach from necrosis caused by absolute ethanol was not impaired by prior exposure to the same dose of acetazolamide.

16,16-Dimethylprostaglandin E2↗
PubMed1984

Addition of the effects of norepinephrine and acetazolamide to decrease formation of cerebrospinal fluid.

In a system for ventriculocisternal perfusion of the choroid plexus, the rate of formation of new cerebrospinal fluid was measured by changes in dilution of an impermeant dye in the perfusate. Norepinephrine added to the perfusate decreased formation of cerebrospinal fluid in rats as was previously demonstrated in rabbits. The dose-response relationship for rats was determined. The formation rate was decreased 42% by 10(-3) M norepinephrine. Acetazolamide, 50 mg/kg i.v., caused a decrease of 46%. Given together, these drugs decreased formation 79%, demonstrating essentially full addition between the regulatory mechanisms involved. Addition of equal magnitude occurred when intraventricular nialamide, an inhibitor of monoamine oxidase, and i.v. acetazolamide were given together. This demonstrates addition between acetazolamide and endogenous norepinephrine (or other catecholamines present) in which metabolic breakdown is prevented by the inhibitor. The degree of reduction in cerebrospinal fluid formation seen in these experiments exceeds that reported for numerous other trials of single drugs.

Acetazolamide↗
PubMed1982

Ocular and systemic effects of acetazolamide in nephrectomized rabbits.

The effects of acetazolamide on intraocular pressure (IOP) were studied on rabbits previously nephrectomized to eliminate the renal effects of the drug. Administration of acetazolamide (5 mg/kg i.v.) reduced IOP from a baseline of 15.2 to 12.2 mm Hg 2 hr later. This dose was found not to alter arterial blood pH, pCO2, bicarbonate, or base excess. However, 4 hr after drug administration anterior chamber aqueous humor showed significant reductions in bicarbonate, pH, and base excess, whereas aqueous humor ascorbate was significantly elevated. Administration of acetazolamide 15 to 50 mg/kg i.v.) to nephrectomized rabbits caused significant acidosis and pCO2 retention, presumably related to red blood cell carbonic anhydrase inhibition. IOP reduction at these higher doses was greater than that which followed the 5 mg/kg administration.

Acetazolamide↗
PubMed1982

The effect of acetazolamide on the proteinuria of altitude.

Albumin was measured by dipstick tests and immunologically in 24-h and early morning urine (EMU) samples collected from 20 subjects during a high-altitude trek. Each was given acetazolamide (Diamox sustets) or placebo as part of a double-blind trial on the prophylactic use of acetazolamide in acute mountain sickness (AMS). At the highest altitudes, albuminuria was six times greater in those on placebo (p less than 0.001) and was related to the clinical features of AMS (p less than 0.01) and arterial oxygen tension (p less than 0.001). Urine dipsticks tests for proteinuria were also an index of AMS, but were inaccurate. The proteinuria is probably due to renal hypoxia, which causes increased glomerular permeability, reduced tubular readsorption, or both. The reduction in the clinical features of AMS achieved with acetazolamide therapy is also associate with improved renal function.

Acetazolamide↗
PubMed1978

[Periodic familial paralysis with hypokalemia. Hemodynamic and metabolic studies: favourable effect of acetazolamide (author's transl)].

The same protocol was used three times to produce a paralytic episode in a typical case of periodic familial paralysis with hypokalemia. This consisted of an effort together with a perfusion of hypertonic glucose serum and insulin. The first test provoked an attach of hypokalemic tetraplegia. The second test, two months after treatment with 500 mg daily of acetazolamide, produced no reaction. In the third test, the metabolic acidosis caused by acetazolamide was reduced by the injection of sodium bicarbonate, and a stronger effect than in the first test was observed. This confirms the efficacy of acetazolamide as a preventive treatment for paralytic attacks; the most reasonable hypothesis being that it acts through the metabolic acidosis that it induces. Metabolic and hemodynamic studies were carried out during the provoked attacks. Cardiac output and oxygen consumption are increased, while pulmonary capillary pressure and periopheral resistance are reduced. Diastolic pressure is lower when measured by an arm-cuff but shows no change when direct readings are taken in the blood-vessels. These results suggest that there is an increase in cellular energy needs, or that the smooth muscle in the vessel walls is paralyzed. The two tetraplegic attacks in tests 1 and 3 were associated with a metabolic acidosis, which is explained by a simultaneous transfer, though in the opposite direction, of H+ and K+ ions; the intra-cellular pH, as measured by the D.M.O. technique, was acid when there was not an attack, and this increased during paralysis.

Acetazolamide↗
PubMedDate not supplied

Acetazolamide therapy evaluation in haemorrhagic stroke.

The influence of acetazolamide in patients with hemorrhagic stroke was assessed in 54 patients in comparison with the influence of other therapies in 68 patients included in a control group. Modified Rankin Scale and mortality rate were evaluated at three different moments: onset, 72 hours and control (3 weeks-one month from the onset). A better outcome was seen when acetazolamide was given. Mortality rate was significantly lower in the group of acetazolamide. This therapy may be safely used in haemorrhagic stroke, especially when hydrocephalus is associated.

Acetazolamide↗
PubMed1995

The effects of acetazolamide on the electroretinographic responses in rats.

PURPOSE: To study the mechanisms and sites of action of the carbonic anhydrase inhibitor, acetazolamide (AZM), on the rod- and cone-mediated electroretinogram (ERG) of the dark-adapted rat. METHODS: After a within-subjects design, ERG responses to brief, full-field flashes were recorded from adult (60 to 90 days old) albino rats, with and without AZM (5 mg/100 g, intraperitoneally). Flickering stimuli (6 and 26 Hz) were used to study rod- and cone-mediated responses. Aspartate-isolated responses of the isolated retina were recorded with and without AZM in the superfusate. The a-wave and PIII responses were fitted with a model of the rod's response by estimating the maximum response (Rmp3), sensitivity (S), and delay td. The b-wave response amplitude and implicit time were examined as a function of stimulus energy. The parameters obtained in the AZM-treated and untreated conditions were compared. RESULTS: Acetazolamide causes a significant decrease in saturated rod response, b-wave amplitude, aspartate-isolated PIII, and the rod- and cone-mediated responses to flickering light. The estimated sensitivity of the rod response (S), b-wave sensitivity, and b-wave implicit time are not altered significantly by AZM. CONCLUSION: Acetazolamide, probably through mechanisms that acidify the retina, attenuates the amplitudes of the retinal responses without significant effect on sensitivity.

Acetazolamide↗
PubMed1994

Effect of timolol vs. acetazolamide on sodium hyaluronate-induced rise in intraocular pressure after cataract surgery.

This prospective study was done to compare the efficacy of timolol and acetazolamide in lowering the intraocular pressure (IOP) secondary to the use of sodium hyaluronate (Healon) in cataract surgery. Fifty patients undergoing extracapsular cataract extraction and implantation of a posterior chamber lens were randomly assigned to one of four treatment groups: no viscoelastic (10 patients), Healon with 0.5% timolol drops postoperatively (12 patients), Healon with acetazolamide postoperatively (16 patients), or Healon only (12 patients). The IOP was measured during the first 24 hours after surgery. Sodium hyaluronate caused a marked increase in IOP in the early (6 to 12 hours) postoperative period. Timolol proved to be more effective than acetazolamide in controlling this pressure increase.

Acetazolamide↗
PubMed1994

[Linealization correction for acetazolamide (Diamox) 99mTc-HMPAO SPECT image--a comparative study with PET].

We attempted to make a linearization correction for the acetazolamide 99mTc-HMPAO SPECT image. These results were compared to those by PET using the H2(15)O-bolus injection method. The subjects consisted of eleven patients with cerebrovascular diseases. The SPECT images were obtained by the double injection method in the resting state and after an administration of acetazolamide (1 g). Linearization correction was performed according to the Lassen's method. In this study, three different methods were compared, namely fixed Fr and alpha (70 ml/min/100 ml and 1.08), individual determination of Fr and alpha based on PET data, and finally the normalization of the two scan for administered dose, fixed Fr and alpha (50 ml/min/100 ml and 1.5). The corrected count rate ratios of the 99mTc-HMPAO SPECT images were correlated well with the values of regional cerebral blood flow measured by PET in all methods. Therefore, the first method was considered to be a simple and reliable one. In the last method, the relative change of cerebral blood flow after the administration of acetazolamide was calculated. The means of the percentage increase of cerebral blood flow were in good accord between 99mTc-HMPAO SPECT and PET. However, they showed much discrepancy when individually compared.

Acetazolamide↗
PubMed1994

[A quantitative approach to the rCBF response to acetazolamide using 99mTc-HMPAO and graphical analysis].

A simple noninvasive method for a quantitative measurement of brain perfusion is presented using intravenous radionuclide angiography with 99mTc-hexamethylpropylene amine oxime (HMPAO). Graphical analysis was employed for the evaluation of the unidirectional influx constant (ku) of the tracer from the blood to the brain and the initial distribution volume (Vn) for the tracer, which is the volume of the exchangeable region plus the plasma space. The ku and Vn values were standardized to provide objective and comparable values, brain perfusion indices (BPI) and corrected Vn (Corr. Vn), between subjects by setting the size ratio of ROI(brain) to ROI(aorta) at 10 and 1, respectively. BPI and Corr. Vn of the whole brain were measured before and 20 min after injection of 1 g acetazolamide. After acetazolamide administration, BPI and Corr. Vn increased in all eight subjects with cerebrovascular diseases and one with a pituitary adenoma, by a mean of x 1.26 and 1.24, respectively. Increase of BPI showed a significant correlation with increase of Corr. Vn. This technique is easy to apply as an adjunct to SPECT and may be helpful in the measurement of brain perfusion changes in the acetazolamide test.

Acetazolamide↗
PubMed1994

Vitreoretinal toxicity of acetazolamide following intravitreal administration in the rabbit eye.

Acetazolamide, a carbonic anhydrase inhibitor, has been shown effective in the treatment of cystoid macular edema; however, chronic use of the drug is limited by its serious systemic side effects. Intraocular administration can eliminate these systemic complications. We evaluated vitreoretinal toxicity after intravitreal injection of acetazolamide in the rabbit eye. The right eye of each rabbit received a single acetzolamide injection; the left eye received balanced salt solution and served as a control. The effect of the drug was evaluated by clinical observation, electroretinography, and histopathologic study. Intravitreal injection of up to 0.5 mg acetazolamide did not cause vitreoretinal toxicity. Injection of 1 mg or higher doses depressed the b-wave amplitude of electroretinograms and damaged the outer segments of the photoreceptors, as determined by light and electron microscopy.

Acetazolamide↗
PubMedDate not supplied

[The therapeutic acetazolamide test in the differentiation between beign and malignant ulcer].

The inhibitory action of acetazolamide on the gastric secretion and its favorable effects in the treatment of gastric ulcers being known, we have applied the therapeutic test with acetazolamide in differentiating benignant from malignant gastric ulcers. The inhibiting pharmacoagent was administered orally in doses of 25-30 mg/kg of body weight. Two hundred and forty-two (242) patients presenting a crater in the radiological image. The fundamental criteria was the size of the crater observed in the radiological examination. In all the cases of gastric ulcer the size of the cavity was considerably reduced after 7-9 days of treatment with acetazolamide, disappearing after about 2-3 weeks. The favorable evolution was obtained in the absence of special diet or bed rest. In 16 cases in which no radiological modifications in the cavity appeared after 7-9 days of treatment, the malignant nature was confirmed. Because of its simplicity and the efficiency of its results, the method can constitute a quick therapeutic test in the differentiation between a benign and a malignant cavity.

Acetazolamide↗
PubMed1993

Effects of acetazolamide on overnight oxygenation and acute mountain sickness in patients with asthma.

The aim of the study was to assess effects of acetazolamide in prevention of acute mountain sickness (AMS) and on overnight oxygenation, in patients with asthma treated at the altitude of 3,200 m. Sixteen patients with asthma, 6 males and 10 females, mean age 32 yrs, were first investigated at low altitude (760 m). They presented with mild airways obstruction, normal arterial blood gases, and normal oxygenation at night studied by pulse oximetry. After initial investigations, patients were divided by random number into the treated (T) and control (C) groups of eight patients each. T group patients received acetazolamide, 750 mg daily for 2 days, before the ascent and on the first day at altitude (3,200 m). Symptoms of AMS developed in seven patients from group C and in three from group T. The overnight pulse oximetry, performed on the first night at altitude, revealed that group T patients had statistically higher (p < 0.05) initial, 91 vs 87%, mean, 90 vs 86%, and minimum, 84 vs 75%, arterial oxygen saturation than group C patients. Overnight pulse oximetry was repeated on the 5th, 10th and 17th day at altitude, and showed that in group C patients, from the 5th day onwards, oxygenation improved to the level observed in group T patients on the first night. We conclude that pretreatment with acetazolamide before the ascent prevented patients with asthma from developing symptoms of AMS, and alleviated acute changes in arterial oxygen saturation brought about by the high altitude hypoxia.

Acclimatization↗
PubMed1977

Acetazolamide-accelerated anticonvulsant osteomalacia.

Severe osteomalacia was present in two epileptic patients who were under long-term treatment with congeners of phenytoin, phenobarbital, and acetazolamide. These patients showed slightly low serum calcium, normal or low serum phosphate, and normal parathyroid hormone concentrations. Discontinuation of acetazolamide produced an immediate threefold drop in the level of urinary calcium excretion and a slight rise in tubular reabsorption of phosphate, with no dectectable change in serum calcium or phosphate concentrations. Acetazolamide may have accelerated the development of osteomalacia by several mechanisms, including increased renal calcium excretion.

Acetazolamide↗
PubMed1996

[Postoperative course of intraocular pressure after uncomplicated cataract operation with and without acetazolamide].

We prospectively analyzed the course of intraocular pressure (IOP) within the first 20 h after uncomplicated phacoemulsification with lens-implantation in the capsule sac with and without acetazolamide. Sixty patients were divided into two groups with 30 patients each, group 1 [mean age 72.3 years, (49-88 years); preoperative IOP 14.2 +/- 2.41 mmHg (10-18 mmHg)] did not receive systemic IOP-lowering medication; group 2 [mean age 72.4 years, (53-88 years); preoperative IOP 14.7 +/- 2.98 mmHg, (9-20 mmHg)] received .250 mg acetazolamide intravenously immediately after surgery. The IOP was measured 6 and 20 h postoperatively with an applanation tonometer. In group 1 the IOP was 17.9 +/- 5.50 mmHg (7-28 mmHg) after 6 h, in group 2 16.6 +/- 5.51 mmHg (9-32 mmHg). In group 1, 8 patients (26.6%) had an IOP of more than 21 after 6 h and in group 2, 6 patients (20%). Statistically, there was no significant difference between groups after 6 h (P > 0.05). After 20 h the IOP was 15.9 +/- 4.50 mmHg (7-28 mmHg) in group 1 and 13.5 +/- 4.46 mmHg (7-26 mmHg) in group 2. Additionally, the two groups tended to be equal with 2 patients each with an IOP of more than 21 mmHg. After 20 h, there was a significant reduction in the IOP each group. Intravenous acetazolamide (250 mg) did not have a clinical relevant influence on IOP after uncomplicated phacoemulsification.

Acetazolamide↗
PubMed1996

[Positional impedance tests with acetazolamide: a clinical test for evaluating endolymphatic hydrops].

The authors report on the possible advantages acetazolamide, in conjunction with Positional Impedenzometry, can provide in the detection of minor labyrinthine hydrops and major labyrinthine fluid tension disorders. This study was carried out using the case/control method. The subjects were selected on the basis of symptoms and clinical examination revealing signs of endolymphatic hydrops. Tonal audiometry and positional impedenzometry according to Marullo were performed both before (pre-test) and after i.v. administration of 500 mg sodium acetazolamide (post-ACZ1 and post-ACZ2). Audiometry showed that in 77.2% of the cases there was a significant variation in threshold. In positional impedenzometry the average post-ACZ1 (delta PISC went from 22.06% (pre-test) to 13.16% and the post-ACZ2 (delta PISC went to 23.15%). On the other hand no significant changes were seen in the controls. Some hypotheses are offered on the mechanisms giving rise to these effects and particular attention is focused on the effect acetazolamide has on the carbon dioxide in the endolymphatic sac. In conclusion the authors consider the advantages this method offers over the "classical" tests used in diagnosing Ménière's Disease and minor hydrops.

Acetazolamide↗
PubMed1997

[Quantitative evaluation of response at acetazolamide test using 99mTc-ECD SPECT; a trial of production of the response map].

In the method by Matsuda and Takeuchi et al. for easy regional cerebral blood flow (rCBF) measurements at pre- and post-acetazolamide tests using 99mTc-ECD, a study was done for producing the increase rate of rCBF as a response map after acetazolamide administration. To prepare the response map calculated from the arithmetic operation of [(rCBF image at administration--rCBF image at rest)/rCBF image at rest x 100], the images were preprocessed by combination of matrix size conversion and smoothing techniques and then areas outside the brain were masked to remove amplified noises. The response map seemed helpful for visual evaluation of the response after acetazolamide administration, and also for understanding the disease conditions and clinical courses.

Acetazolamide↗
PubMed1998

[A study on accuracy of rCBF measurements loaded with acetazolamide based on the microsphere model using iodine-123-IMP SPECT].

We studied the accuracy of the method for measuring regional cerebral blood flow (rCBF) loaded with acetazolamide based on the microsphere model using iodine-123-IMP (IMP) SPECT. Two methods were examined, the super-early microsphere method with continuous withdrawal of arterial blood using the SPECT image obtained 5 min after tracer injection and the early microsphere method with one-point arterial sampling using the SPECT image obtained 30 min postinjection. On five subjects, after acetazolamide administration we measured rCBF by the analysis based on the two-compartment model using the data derived from dynamic SPECT scans and the sequential arterial blood sampling after IMP injection. Values of rCBF obtained by both super-early microsphere method and early microsphere method were significantly correlated with those obtained by the two-compartment model analysis (r = 0.982, 0.930, respectively). We conclude that it is possible to use the method based on the microsphere model in measuring rCBF loaded with acetazolamide. The early microsphere method with one-point sampling should be used clinically because of its simplicity and less-invasiveness.

Acetazolamide↗