Acute Myopic Shift after a Single Dose of Acetazolamide: A Case Report and Review of the Literature

We report the case of a 32-year-old male who presented with an acute myopic shift as a result of uveal effusion following a single administration of 250 mg acetazolamide. The drug was discontinued and following cycloplegia and topical steroid therapy, we observed progressive deepening of the anterior chamber, reopening of the iridocorneal angle, and complete resolution of the myopic shift after 5 days. A literature review since 1956 identified 23 cases, including ours, which developed a myopic shift after a median time of 24 h (3 - 24) following a median dose of 500 mg (125 - 1000) acetazolamide, with about a third complicated by angle closure ocular hypertension. This presumed idiosyncratic reaction can occur without prior drug exposure and independent of the phakic status. Treatment options include systematic drug withdrawal associated with cycloplegia, anti-glaucomatous agents, and/or corticosteroids. Full recovery is achieved within about 5 days (2 - 14). Given the widespread use of acetazolamide, awareness of this idiosyncratic reaction is crucial to avoid complications of acute angle-closure glaucoma.

The manifestations of metabolic acidosis during acetazolamide treatment in a cohort of pediatric idiopathic intracranial hypertension

BACKGROUND

Idiopathic intracranial hypertension is characterized by increased intracranial pressure with unidentified pathology. Despite its use as the first-line treatment, data on acetazolamide's effectiveness and safety in pediatric idiopathic intracranial hypertension is sparse. This study's objective was to assess those issues and the need for routine blood gas monitoring during treatment.

METHODS

Retrospective observational cohort study, based on multicenter computerized medical charts of pediatric patients with idiopathic intracranial hypertension diagnosed between 2007-2018 in three medical centers serving one metropolitan area (an estimated population of 400,000 children). Clinical and laboratory data of children up to 18 years old, fulfilling the Friedman criteria and taking acetazolamide, were collected and analyzed.

RESULTS

Sixty-eight patients were included with a mean acetazolamide treatment duration of 8.5 months and a median maximal dose 18 mg/kg/d. Sixty-two children had mild (76%), moderate (13%), or severe (1.5%) metabolic acidosis. At least one adverse effect (neurologic, gastrointestinal, renal) was recorded among 27% of patients. No significant difference was found between the mean pH of children with or without clinical adverse effects (p = 0.35). No correlation was found between laboratory acidosis and adverse effect severity (p = 0.3), or between median acetazolamide dose and acidosis level (p = 0.57).

CONCLUSIONS

Although laboratory finding of metabolic acidosis is common among patients with idiopathic intracranial hypertension treated with acetazolamide, it is not correlated with clinics. Therefore, we recommend sending blood tests during acetazolamide treatment based on clinical judgment. A higher resolution version of the Graphical abstract is available as Supplementary information.

Intravenous or Oral Acetazolamide for Treatment of Diuretic-Induced Alkalosis in Patients With Heart Failure

BACKGROUND

Acetazolamide has been used for diuretic-induced metabolic alkalosis, but the preferred dose, route, and frequency of administration remain unknown.

OBJECTIVE

The purpose of this study was to characterize dosing strategies and determine the effectiveness of intravenous (IV) and oral (PO) acetazolamide for patients with heart failure (HF) with diuretic-induced metabolic alkalosis.

METHODS

This was a multicenter, retrospective cohort study comparing the use of IV versus PO acetazolamide in patients with HF receiving at least 120 mg of furosemide for the treatment of metabolic alkalosis (serum bicarbonate CO2 ≥32). The primary outcome was the change in CO2 on the first basic metabolic panel (BMP) within 24 hours of the first dose of acetazolamide. Secondary outcomes included laboratory outcomes, such as change in bicarbonate, chloride, and incidence of hyponatremia and hypokalemia. This study was approved by the local institutional review board.

RESULTS

IV acetazolamide was given in 35 patients and PO acetazolamide was given in 35 patients. Patients in both groups were given a median of 500 mg of acetazolamide in the first 24 hours. For the primary outcome, there was a significant decrease in CO2 on the first BMP within 24 hours after patients received the IV acetazolamide (-2 [interquartile range, IQR: -2, 0] vs 0 [IQR: -3, 1], P = 0.047). There were no differences in secondary outcomes.

CONCLUSION AND RELEVANCE

IV acetazolamide resulted in significantly decreased bicarbonate within 24 hours of administration. IV acetazolamide may be preferred to treat diuretic-induced metabolic alkalosis in patients with HF.

Acetazolamide in Acute Decompensated Heart Failure with Volume Overload

BACKGROUND

Whether acetazolamide, a carbonic anhydrase inhibitor that reduces proximal tubular sodium reabsorption, can improve the efficiency of loop diuretics, potentially leading to more and faster decongestion in patients with acute decompensated heart failure with volume overload, is unclear.

METHODS

In this multicenter, parallel-group, double-blind, randomized, placebo-controlled trial, we assigned patients with acute decompensated heart failure, clinical signs of volume overload (i.e., edema, pleural effusion, or ascites), and an N-terminal pro-B-type natriuretic peptide level of more than 1000 pg per milliliter or a B-type natriuretic peptide level of more than 250 pg per milliliter to receive either intravenous acetazolamide (500 mg once daily) or placebo added to standardized intravenous loop diuretics (at a dose equivalent to twice the oral maintenance dose). Randomization was stratified according to the left ventricular ejection fraction (≤40% or >40%). The primary end point was successful decongestion, defined as the absence of signs of volume overload, within 3 days after randomization and without an indication for escalation of decongestive therapy. Secondary end points included a composite of death from any cause or rehospitalization for heart failure during 3 months of follow-up. Safety was also assessed.

RESULTS

A total of 519 patients underwent randomization. Successful decongestion occurred in 108 of 256 patients (42.2%) in the acetazolamide group and in 79 of 259 (30.5%) in the placebo group (risk ratio, 1.46; 95% confidence interval [CI], 1.17 to 1.82; P<0.001). Death from any cause or rehospitalization for heart failure occurred in 76 of 256 patients (29.7%) in the acetazolamide group and in 72 of 259 patients (27.8%) in the placebo group (hazard ratio, 1.07; 95% CI, 0.78 to 1.48). Acetazolamide treatment was associated with higher cumulative urine output and natriuresis, findings consistent with better diuretic efficiency. The incidence of worsening kidney function, hypokalemia, hypotension, and adverse events was similar in the two groups.

CONCLUSIONS

The addition of acetazolamide to loop diuretic therapy in patients with acute decompensated heart failure resulted in a greater incidence of successful decongestion. (Funded by the Belgian Health Care Knowledge Center; ADVOR ClinicalTrials.gov number, NCT03505788.).

Brief report: Metabolic acidosis in newborn infants following maternal use of acetazolamide during pregnancy

 The information regarding fetal effects of acetazolamide use during pregnancy and lactation is sparse. We report the clinical and pharmacodynamic characteristics of maternal acetazolamide use and the timing of its effects on acid-base balance in three cases who presented with metabolic acidosis in the newborn period. We found that the infants' clinical status soon after birth was inconsistently correlated with maternal drug dose and concentrations of medication in maternal serum. However, there was low transfer of the drug in breast milk and its use did not affect clinical symptomatology. We also present a review of literature on this subject to help consolidate our current knowledge on this topic.

The usefulness of prophylactic use of acetazolamide in subjects with acute mountain sickness

BACKGROUND

The mechanisms of acetazolamide (ACZ) in the prophylaxis of acute mountain sickness (AMS) remain unclear. This study evaluated the changes in physiological variables of sleep and heart rate variability (HRV) in subjects with earlier history of AMS who underwent prophylactic treatment of ACZ.

METHODS

Nonacclimatized healthy subjects were transported using a bus from 555 m to 3150 m within 3 hours. Polysomnography (PSG) was performed 3 days before ascent (T0), for two consecutive nights at 3150 m (T1 and T2), and 2 days after descent (T3). HRV was measured before sleep and after awakening from T0 to T3. AMS was diagnosed using a self-reported Lake Louise score questionnaire. Subjects found confirmed to have AMS were enrolled in this study. The physiological variables and HRV were compared in AMS subjects without (control group) and with prophylactic ACZ (prophylactic ACZ group).

RESULTS

Thirteen AMS subjects were enrolled. The PSG results were analyzed in eight and HRV were analyzed in nine of the 13 subjects. The prophylactic use of ACZ in the subjects with a history of AMS significantly improved sleep efficiency (p = 0.012) and awakening percentages (p = 0.017) at T1, significantly higher levels of arterial oxygen saturation (SaO2) and lower values of partial pressure end-tidal carbon dioxide tension (PETCO2) at four time points. Furthermore, they had a higher rapid eye movement sleep percentage (p = 0.05) at T2. Prophylactic ACZ treatment significantly increased the normalized unit of high frequency at T1 after awakening (p = 0.028).

CONCLUSION

Significantly higher quality of sleep, higher SaO2 during sleep, and lower PETCO2 at high altitude were found in the subjects with a history of AMS using prophylactic ACZ before rapid ascent. ACZ may accelerate the acclimatization process for rapid ascents to high altitudes by increasing parasympathetic tone based on HRV analyses.

Treatment for HIV-associated cryptococcal meningitis

BACKGROUND

Cryptococcal meningitis is a severe fungal infection that occurs primarily in the setting of advanced immunodeficiency and remains a major cause of HIV-related deaths worldwide. The best induction therapy to reduce mortality from HIV-associated cryptococcal meningitis is unclear, particularly in resource-limited settings where management of drug-related toxicities associated with more potent antifungal drugs is a challenge.

OBJECTIVES

To evaluate the best induction therapy to reduce mortality from HIV-associated cryptococcal meningitis; to compare side effect profiles of different therapies.

SEARCH METHODS

We searched the Cochrane Infectious Diseases Group Specialized Register, CENTRAL, MEDLINE (PubMed), Embase (Ovid), LILACS (BIREME), African Index Medicus, and Index Medicus for the South-East Asia Region (IMSEAR) from 1 January 1980 to 9 July 2018. We also searched the World Health Organization International Clinical Trials Registry Platform (WHO ICTRP), ClinicalTrials.gov, and the ISRCTN registry; and abstracts of select conferences published between 1 July 2014 and 9 July 2018.

SELECTION CRITERIA

We included randomized controlled trials that compared antifungal induction therapies used for the first episode of HIV-associated cryptococcal meningitis. Comparisons could include different individual or combination therapies, or the same antifungal therapies with differing durations of induction (less than two weeks or two or more weeks, the latter being the current standard of care). We included data regardless of age, geographical region, or drug dosage. We specified no language restriction.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened titles and abstracts identified by the search strategy. We obtained the full texts of potentially eligible studies to assess eligibility and extracted data using standardized forms. The main outcomes included mortality at 2 weeks, 10 weeks, and 6 months; mean rate of cerebrospinal fluid fungal clearance in the first two weeks of treatment; and Division of AIDS (DAIDS) grade three or four laboratory events. Using random-effects models we determined pooled risk ratio (RR) and 95% confidence interval (CI) for dichotomous outcomes and mean differences (MD) and 95% CI for continuous outcomes. For the direct comparison of 10-week mortality, we assessed the certainty of the evidence using the GRADE approach. We performed a network meta-analysis using multivariate meta-regression. We modelled treatment differences (RR and 95% CI) and determined treatment rankings for two-week and 10-week mortality outcomes using surface under the cumulative ranking curve (SUCRA). We assessed transitivity by comparing distribution of effect modifiers between studies, local inconsistency through a node-splitting approach, and global inconsistency using design-by-treatment interaction modelling. For the network meta-analysis, we applied a modified GRADE approach for assessing the certainty of the evidence for 10-week mortality.

MAIN RESULTS

We included 13 eligible studies that enrolled 2426 participants and compared 21 interventions. All studies were carried out in adults, and all but two studies were conducted in resource-limited settings, including 11 of 12 studies with 10-week mortality data.In the direct pairwise comparisons evaluating 10-week mortality, one study from four sub-Saharan African countries contributed data to several key comparisons. At 10 weeks these data showed that those on the regimen of one-week amphotericin B deoxycholate (AmBd) and flucytosine (5FC) followed by fluconazole (FLU) on days 8 to 14 had lower mortality when compared to (i) two weeks of AmBd and 5FC (RR 0.62, 95% CI 0.42 to 0.93; 228 participants, 1 study), (ii) two weeks of AmBd and FLU (RR 0.58, 95% CI 0.39 to 0.86; 227 participants, 1 study), (iii) one week of AmBd with two weeks of FLU (RR 0.49, 95% CI 0.34 to 0.72; 224 participants, 1 study), and (iv) two weeks of 5FC and FLU (RR 0.68, 95% CI 0.47 to 0.99; 338 participants, 1 study). The evidence for each of these comparisons was of moderate certainty. For other outcomes, this shortened one-week AmBd and 5FC regimen had similar fungal clearance (MD 0.05 log₁₀ CFU/mL/day, 95% CI -0.02 to 0.12; 186 participants, 1 study) as well as lower risk of grade three or four anaemia (RR 0.31, 95% CI 0.16 to 0.60; 228 participants, 1 study) compared to the two-week regimen of AmBd and 5FC.For 10-week mortality, the comparison of two weeks of 5FC and FLU with two weeks of AmBd and 5FC (RR 0.92, 95% CI 0.69 to 1.23; 340 participants, 1 study) or two weeks of AmBd and FLU (RR 0.85, 95% CI 0.64 to 1.13; 339 participants, 1 study) did not show a difference in mortality, with moderate-certainty evidence for both comparisons.When two weeks of combination AmBd and 5FC was compared with AmBd alone, pooled data showed lower mortality at 10 weeks (RR 0.66, 95% CI 0.46 to 0.95; 231 participants, 2 studies, moderate-certainty evidence).When two weeks of AmBd and FLU was compared to AmBd alone, there was no difference in 10-week mortality in pooled data (RR 0.94, 95% CI 0.55 to 1.62; 371 participants, 3 studies, low-certainty evidence).One week of AmBd and 5FC followed by FLU on days 8 to 14 was the best induction therapy regimen after comparison with 11 other regimens for 10-week mortality in the network meta-analysis, with an overall SUCRA ranking of 88%.

AUTHORS' CONCLUSIONS

In resource-limited settings, one-week AmBd- and 5FC-based therapy is probably superior to other regimens for treatment of HIV-associated cryptococcal meningitis. An all-oral regimen of two weeks 5FC and FLU may be an alternative in settings where AmBd is unavailable or intravenous therapy cannot be safely administered. We found no mortality benefit of combination two weeks AmBd and FLU compared to AmBd alone. Given the absence of data from studies in children, and limited data from high-income countries, our findings provide limited guidance for treatment in these patients and settings.

Interventions for preventing high altitude illness: Part 1. Commonly-used classes of drugs

BACKGROUND

High altitude illness (HAI) is a term used to describe a group of cerebral and pulmonary syndromes that can occur during travel to elevations above 2500 metres (8202 feet). Acute hypoxia, acute mountain sickness (AMS), high altitude cerebral oedema (HACE) and high altitude pulmonary oedema (HAPE) are reported as potential medical problems associated with high altitude. In this review, the first in a series of three about preventive strategies for HAI, we assess the effectiveness of six of the most recommended classes of pharmacological interventions.

OBJECTIVES

To assess the clinical effectiveness and adverse events of commonly-used pharmacological interventions for preventing acute HAI.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (OVID), Embase (OVID), LILACS and trial registries in January 2017. We adapted the MEDLINE strategy for searching the other databases. We used a combination of thesaurus-based and free-text terms to search.

SELECTION CRITERIA

We included randomized-controlled and cross-over trials conducted in any setting where commonly-used classes of drugs were used to prevent acute HAI.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures as expected by Cochrane.

MAIN RESULTS

We included 64 studies (78 references) and 4547 participants in this review, and classified 12 additional studies as ongoing. A further 12 studies await classification, as we were unable to obtain the full texts. Most of the studies were conducted in high altitude mountain areas, while the rest used low pressure (hypobaric) chambers to simulate altitude exposure. Twenty-four trials provided the intervention between three and five days prior to the ascent, and 23 trials, between one and two days beforehand. Most of the included studies reached a final altitude of between 4001 and 5000 metres above sea level. Risks of bias were unclear for several domains, and a considerable number of studies did not report adverse events of the evaluated interventions. We found 26 comparisons, 15 of them comparing commonly-used drugs versus placebo. We report results for the three most important comparisons: Acetazolamide versus placebo (28 parallel studies; 2345 participants)The risk of AMS was reduced with acetazolamide (risk ratio (RR) 0.47, 95% confidence interval (CI) 0.39 to 0.56; I² = 0%; 16 studies; 2301 participants; moderate quality of evidence). No events of HAPE were reported and only one event of HACE (RR 0.32, 95% CI 0.01 to 7.48; 6 parallel studies; 1126 participants; moderate quality of evidence). Few studies reported side effects for this comparison, and they showed an increase in the risk of paraesthesia with the intake of acetazolamide (RR 5.53, 95% CI 2.81 to 10.88, I² = 60%; 5 studies, 789 participants; low quality of evidence). Budenoside versus placebo (2 parallel studies; 132 participants)Data on budenoside showed a reduction in the incidence of AMS compared with placebo (RR 0.37, 95% CI 0.23 to 0.61; I² = 0%; 2 studies, 132 participants; low quality of evidence). Studies included did not report events of HAPE or HACE, and they did not find side effects (low quality of evidence). Dexamethasone versus placebo (7 parallel studies; 205 participants)For dexamethasone, the data did not show benefits at any dosage (RR 0.60, 95% CI 0.36 to 1.00; I2 = 39%; 4 trials, 176 participants; low quality of evidence). Included studies did not report events of HAPE or HACE, and we rated the evidence about adverse events as of very low quality.

AUTHORS' CONCLUSIONS

Our assessment of the most commonly-used pharmacological interventions suggests that acetazolamide is an effective pharmacological agent to prevent acute HAI in dosages of 250 to 750 mg/day. This information is based on evidence of moderate quality. Acetazolamide is associated with an increased risk of paraesthesia, although there are few reports about other adverse events from the available evidence. The clinical benefits and harms of other pharmacological interventions such as ibuprofen, budenoside and dexamethasone are unclear. Large multicentre studies are needed for most of the pharmacological agents evaluated in this review, to evaluate their effectiveness and safety.

Findings of Cognitive Impairment at High Altitude: Relationships to Acetazolamide Use and Acute Mountain Sickness

Phillips, Lara, Buddha Basnyat, Yuchiao Chang, Erik R. Swenson, and N. Stuart Harris. Findings of cognitive impairment at high altitude: relationships to acetazolamide use and acute mountain sickness. High Alt Med Biol. 18:121-127, 2017.

OBJECTIVE

Acute mountain sickness (AMS) is defined by patient-reported symptoms using the Lake Louise Score (LLS), which provides limited insight into any possible underlying central nervous system (CNS) dysfunction. Some evidence suggests AMS might coexist with altered neural functioning. Cognitive impairment (CI) may go undetected unless a sensitive test is applied. Our hypothesis was that a standardized test for mild CI would provide an objective measure of CNS dysfunction, which may correlate with the symptoms of AMS and so provide a potential new tool to better characterize altitude-related CNS dysfunction. We compared a cognitive screening tool with the LLS to see if it correlated with CNS dysfunction.

METHODS

Adult native English-speaking subjects visiting Himalayan Rescue Association aid stations in Nepal at 3520 m (11,548 ft) and 4550 m (14,927 ft) were recruited. Subjects were administered the LLS and a slightly modified version of the environmental Quick mild cognitive impairment screen (eQmci). Medication use for altitude illness was recorded. Scores were compared using the Spearman's correlation coefficient. Data also included medication use.

RESULTS

Seventy-nine subjects were enrolled. A cut-off of three or greater was used for the LLS to diagnose AMS and 67 or less for the eQmci to diagnose CI. There were 22 (28%) subjects who met criteria for AMS and 17 (22%) subjects who met criteria for CI. There was a weak correlation (r² = 0.06, p = 0.04) between eQmci score and LLS. In matched subjects with identical LLS, recent acetazolamide use was associated with significantly more CI.

CONCLUSION

Field assessment of CI using a rapid standardized tool demonstrated that a substantial number of subjects were found to have mild CI following rapid ascent to 3520-4550 m (11,548-14,927 ft). The weak correlation between the LLS and eQmci suggests that AMS does not result in CI. Use of acetazolamide appears to be associated with CI at all levels of AMS severity.

Severe ocular side effects with acetazolamide: case report

CLINICAL CASE

A 44-year-old woman arrived in the emergency department complaining of decreased visual acuity (VA) in oculus uterque (OU) of 4hours onset. Signs of myopia, increased intraocular pressure (IOP) in OU, and a narrow grade II anterior chamber (AC) were observed. In the posterior segment ultrasound scan, a choroidal peripheral detachment is evident, and a lenticular thickness of 4.05mm is measured in the anterior segment of the right eye (OD) and 4.00mm in the left eye (OS). On treatment with oral with naproxen (non-steroidal anti-inflammatory drug), and acetazolamide for migraine. The acetazolamide is suspended and topical treatment is started with timolol and brimonidine every 12hours, with prednisolone and ayclopentolate every 8hours. In the follow-up, a gradual reduction of myopia and lens thickness is observed, as well as anterior chamber expansion. In the last control, the patient had a sphere of -0.75 diopters (D) in OD and -0.25 D in OS. IOP was 15mmHg in OU and AC was grade III. The ultrasound showed a lens thickness of 3.59mm in OD and 3.61mm in OS.

CONCLUSION

This was an iatrogenic case of acute angle closure induced by an anterior displacement of the irido-lenticular complex, secondary to the use of acetazolamide. The treatment of this condition involves suspending the drug responsible and applying topical corticosteroids, hypotensive and cycloplegic eye drops, with the aim of lowering the eye pressure and the degree of myopia due to the re-positioning of the irido-lenticular complex.

Pseudotumor cerebri: What We Have Learned from the Idiopathic Intracranial Hypertension Treatment Trial

Idiopathic intracranial hypertension, also known as pseudotumor cerebri, is an unexplained increase in intracranial pressure associated with permanent severe visual loss in 25% of cases and debilitating headaches. The condition is often associated with obesity. The Idiopathic Intracranial Hypertension Treatment Trial, a large, randomized, collaborative clinical trial, evaluated the efficacy of acetazolamide with weight loss versus placebo with weight loss in participants. Herein, we describe the major components of the clinical trial and discuss its shortcomings. [Full article available at http://rimed.org/rimedicaljournal-2016-05.asp, free with no login].

Acetazolamide and prevention of acute mountain sickness

When planning a rapid ascent to an altitude above 3000 metres, acetazolamide 250 mg daily reduces the risk of acute mountain sickness, with generally moderate adverse effects.

Clinical practice: Acute high-altitude illnesses

A 45-year-old healthy man wishes to climb Mount Kilimanjaro (5895 m) in a 5-day period, starting at 1800 m. The results of a recent exercise stress test were normal; he runs 10 km 4 or 5 times per week and finished a marathon in less than 4 hours last year. He wants to know how he can prevent becoming ill at high altitude and whether training or sleeping under normobaric hypoxic conditions in the weeks before the ascent would be helpful. What would you advise?

Identifying the lowest effective dose of acetazolamide for the prophylaxis of acute mountain sickness: systematic review and meta-analysis

OBJECTIVES

To assess the efficacy of three different daily doses of acetazolamide in the prevention of acute mountain sickness and to determine the lowest effective dose.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Medline and Embase along with a hand search of selected bibliographies. No language restrictions were applied.

STUDY SELECTION

Randomised controlled trials assessing the use of acetazolamide at 250 mg, 500 mg, or 750 mg daily versus placebo in adults as a drug intervention for the prophylaxis of acute mountain sickness. Included studies were required to state the administered dose of acetazolamide and to randomise participants before ascent to either acetazolamide or placebo. Two reviewers independently carried out the selection process.

DATA EXTRACTION

Two reviewers extracted data concerning study methods, pharmacological intervention with acetazolamide, method of assessment of acute mountain sickness, and event rates in both control and intervention groups, which were verified and analysed by the review team collaboratively.

DATA SYNTHESIS

11 studies (with 12 interventions arms) were included in the review. Acetazolamide at doses of 250 mg, 500 mg, and 750 mg were all effective in preventing acute mountain sickness above 3000 m, with a combined odds ratio of 0.36 (95% confidence interval 0.28 to 0.46). At a dose of 250 mg daily the number needed to treat for acetazolamide to prevent acute mountain sickness was 6 (95% confidence interval 5 to 11). Heterogeneity ranged from I(2)=0% (500 mg subgroup) to I(2)=44% (750 mg subgroup).

CONCLUSIONS

Acetazolamide in doses of 250 mg, 500 mg, and 750 mg daily are all more effective than placebo for preventing acute mountain sickness. Acetazolamide 250 mg daily is the lowest effective dose to prevent acute mountain sickness for which evidence is available.

Acetazolamide as an adjunct to CPAP treatment: a case of complex sleep apnea in a patient on long-acting opioid therapy

A 41-year-old white woman on long-acting opioid therapy was diagnosed with moderate obstructive sleep apnea. On initiation of continuous positive airway pressure (CPAP), she manifested severe central apnea that was unresponsive to supplemental oxygen and interfered with CPAP titration. Acetazolamide, 250 mg, nightly at bedtime was initiated, and CPAP titration was repeated. On acetazolamide, optimal CPAP pressure was obtained with no manifestation of clinically significant central respiratory disturbance. This case suggests that acetazolamide may be an effective adjunct to positive airway pressure therapy in patients on long-acting opioids. A need exists for examination of acetazolamide in this capacity.

[Enlargement of cerebral infarction after CBF study with acetazolamide challenge: two case report]

Acetazolamide has been used for a long time for the evaluation of cerebral hemodynamics. Severe side effects as a result of acetazolamide infusion are uncommon. Two patients with unilatral internal carotid artery occlusion presented with enlargement of cerebral infarction after SPECT (single photon emission computed tomography) with acetazolamide challenge. A 60-year-old man and a 72-year-old man suffered from stroke caused by unilateral internal carotid artery occlusion. Both patients underwent SPECT under acetazolamide challenge nine days later and nineteen days later respectively. Neurological symptoms did not change immediately after acetazolamide infusion in either case, but were impaired the next day and two days later respectively. CT and MRI revealed enlargement of the infarction. Both patients had lassitude and loss of appetite after acetazolamide administration, and it was possible that dehydration induced enlargement of the cerebral infarction.

[Periodic paralysis: new pathophysiological aspects]

Periodic paralyses are neuromuscular disorders characterized by attacks of muscle weakness coinciding with changes in blood potassium levels. They are thus classified as hypokalaemic, normokalaemic or hyperkalaemic. Most forms are genetic, with autosomal dominant inheritance. These diseases are channelopathies, i.e. caused by mutations in ion channel genes. The culprit genes encode muscle sodium, calcium and potassium channels. Mutations in calcium or potassium channels cause periodic paralyses of the same type (hypokalaemic periodic paralysis or Andersen-Tawil Syndrome). In contrast, distinct mutations in the gene encoding the sodium channel can cause the entire range of periodic paralysis (hypokalaemic, normokalaemic or hyperkalaemic). The physiological consequences of mutations have been studied with patch-clamp techniques and electromyography. Generally speaking, mutations alter the excitability cycle of the muscle membrane, resulting in a loss of function (paralysis). Electromyographic studies have demonstrated a good correlation between symptoms and physiological parameters, giving rise to a classification that can help orient the molecular diagnosis. Work on the genetics and pathophysiology of periodic paralyses has helped to improve the diagnosis and management of these syndromes.

Treatment of acute cryptococcal meningitis in HIV infected adults, with an emphasis on resource-limited settings

BACKGROUND

Despite the advent and increasingly wide availability of antiretroviral therapy, cryptococcal meningitis (CM) remains a significant cause of mortality and morbidity amongst individuals with HIV infection in resource-limited settings. The ideal management of CM remains unclear. The aim of this review is to assess the evidence for deciding on which antifungal regimen to use as well as other modalities of management to utilise especially resource poor settings in order to achieve the best possible outcome and enable an individual with CM to survive their acute illness and benefit from antiretroviral therapy.

OBJECTIVES

To determine the most effective initial and consolidation treatment strategy for CM in HIV infected adults.

SEARCH STRATEGY

The Cochrane HIV/AIDS group search strategy was used. Key words in the search included, meningitis, cryptococcus neoformans, treatment, trial, human immunodeficiency virus, acquired immunodeficiency syndrome, antifungal agents, amphotericin, flucytosine, fluconazole, azole, lumbar puncture, cerebrospinal fluid (CSF) pressure and acetazolamide.

SELECTION CRITERIA

Randomised of HIV-infected adults with a first episode of CM diagnosed on CSF examination, by India ink staining, CSF culture or cryptococcal antigen testing.

DATA COLLECTION AND ANALYSIS

Data were extracted using standardised forms and analysed using Rev Man 4.2.7 software.

MAIN RESULTS

Six studies are included in the review. Five of the studies compared antifungal treatments and one study addressed lowering intracranial pressure. This study was stopped early due to excess adverse effects. The results of the other five studies as summarised as follows.Mayanja-Kizza 1998 compared fluconazole to fluconazole with 5 flucytosine. The dose of fluconazole used 200mg initially is lower than the recommended initial dose of 400mg. No survival advantage was found with the use of 5 flucytosine in addition to fluconazole.Two studies Brouwer 2004 and van der Horst 1997 compared Amphotericin (AmB) to AmB with 5 flucytosine. Both drugs were given at currently recommended doses for 2 weeks. No survival difference was found at 14 days or at 10 weeks (only recorded in Brouwer 2004). There were significantly more patients with sterile CSF cultures at 14 days in the group that received AmB with flucytosine.Brouwer 2004 compared AmB given alone to AmB given with flucytosine and fluconazole alone or in combination. This was a small study and no differences in mortality were noted between the groups.Bicanic 2008 compared high to standard dose AmB both with flucytosine. There was no difference in mortality between the two groups or adverse events.Leenders 1997 compared standard AmB to liposomal AmB. There was no difference in death rates between the two groups. But there were significantly fewer side effects in the group treated with liposomal AmB.

AUTHORS' CONCLUSIONS

The main aim of this review was to determine the best treatment for cryptococcal meningitis in resource-limited settings. In these settings usually only AmB and fluconazole are available. No studies suitable for inclusion in the review were found that compared these two drugs. Therefore we are unable to recommend either treatment as superior to the other. The recommended treatment for CM is a combination of AmB and flucytosine. The optimal dosing of AmB remains unclear. Liposomal AmB is associated with less adverse events than AmB and may be useful in selected patients where resources allow.Future research into the management of cryptococcal meningitis in resource-limited settings should focus on the most effective use of medications that are available in these settings.Flucytosine in combination with AmB leads to faster and increased sterilisation of CSF compared to using AmB alone. As Flucytosine is often not available in developing countries, policy makers and national departments of heath should consider procuring this drug for HIV treatment programmes.

Dermite de contact et acétazolamide par voie topique sous occlusion

INTRODUCTION

Acetazolamide is a carbonic anhydrase inhibitor used topically for local secondary treatment of posttraumatic or postoperative edema.

CASES

Two women had contact dermatitis, secondarily extensive, after local cutaneous use of acetazolamide under a compression panty after liposuction. The eruption disappeared after acetazolamide was stopped and local treatment administered. Cutaneous tests were positive for acetazolamide.

DISCUSSION

Local allergic reactions are mentioned in the monograph on topical acetazolamide. Cases of contact dermatitis from this drug have not so far been published, but French adverse drug reaction reporting data include 10 other cases of eczema or rash at the application site. In one of these, a positive reaction was observed on readministration, and in 2 cases allergy skin tests were positive. The application of the drug under occlusion, which is contraindicated, may have contributed to spreading the lesions. Cases have also been described with another carbonic anhydrase inhibitor, dorzolamide, used in ophthalmology.

Treatment of idiopathic intracranial hypertension: topiramate vs acetazolamide, an open-label study

OBJECTIVES - To assess the efficacy of topiramate in the treatment of idiopathic intracranial hypertension (IIH) and to compare it with acetazolamide. METHODS - Fourty patients diagnosed as IIH and randomly assigned to treatment with either acetazolamide or topiramate were assessed prospectively. Improvement in the visual fields at the end of third, sixth and twelfth months were taken into consideration. RESULTS - The demographic, clinical features and the cerebrospinal fluid (CSF) pressure of the two treatment groups were similar at the beginning of the study. When the follow-up visual field grades were compared with the visual field grades at the beginning of the study in each group a statistically significant improvement was detected with both drugs. When the results of the two treatment groups were compared with each other no statistically significant difference was present. Prominent weight loss was recorded in the topiramate group. CONCLUSIONS - Topiramate seems to be effective in the treatment of IIH. Weight reduction as well as the reduction of the CSF formation is the possible mechanism of action.

[Ultrastructural evaluation of mitomycin C toxic effects on the ciliary epithelium of normal rabbits eyes with and without aqueous humor suppressant treatment]

PURPOSE

To evaluate the effects of mitomycin C (MMC) on the internal ciliary epithelium (ICE) of the ciliary body of animals treated with two different aqueous humor suppressants.

METHODS

The eyes of sixteen Norfolk albino rabbits divided into four experimental groups were studied. The right eyes (RE) of the four groups received 0.1 ml of MMC (0.5 mg/ml) under the scleral flap. The left eyes (LE) was the control group. Group 1 (G1) did not have any other treatment. To Group 2 (G2) and Group 4 (G4) acetazolamide was administered. To Group (G3) and Group 4 (G4) timolol maleate was administered. ICE was examined by transmission electron microscopy (TEM).

RESULTS

The following aspects were observed in all groups, except in G1 LE: cell shrinkage and/or enlargement of intercellular spaces, rarefied mitochondria, clear vesicular structures and electron-dense bodies. The internal limitant membrane showed to be thickened, discontinued and separated in all groups, except in G1 LE and G2 LE. Discharge of cytoplasmatic material was observed only in the groups treated with aqueous humor suppressants.

CONCLUSIONS

1) MMC, acetazolamide and timolol maleate caused morphological alterations in the ciliary epithelium even when used alone. 2) The combination of MMC and acetazolamide caused more alterations than did isolated acetazolamide, but not more than MMC alone. 3) For the other combinations the alterations were similar.

Cerebral fat embolism syndrome causing brain death after long-bone fractures and acetazolamide therapy

A 19-year-old woman with multiple fractures and mild brain injury developed severe cerebral fat embolism syndrome after "damage control" orthopaedic surgery. Acetazolamide therapy to manage ocular trauma, in association with hyperchloraemia, caused a profound metabolic acidosis with appropriate compensatory hypocapnia. During ventilator weaning, unexpected brainstem coning followed increased sedation and brief normalisation of arterial carbon dioxide concentration. Autopsy found severe cerebral fat embolism and brain oedema. In patients with multiple trauma, cerebral fat embolism syndrome is difficult to diagnose, and may be more common after delayed fixation of long-bone fractures. Acetazolamide should be used with caution, as sudden restoration of normocapnia during compensated metabolic acidosis in patients with raised intracranial pressure may precipitate coning.

[What should we think? Should Diamox and pilocarpine continue to be prescribed?]

Despite well-known adverse effects, pilocarpine and acetazolamide remain useful medications for the therapeutic management of glaucomatous patients.

Bilateral angle closure glaucoma induced by sulphonamide-derived medications

BACKGROUND

Sulphonamide-derived medications are widely used, although not always recognized as such. We report the occurrence of bilateral angle closure glaucoma with sulphonamide-derived medications and highlight features of the presentation and treatment to assist in early diagnosis and management.

METHODS

The clinical records of three cases with bilateral angle closure glaucoma induced by three sulphonamide-derived medications, sulfasalazine, oral acetazolamide, and hydrochlorothiazide, were reviewed.

RESULTS

All three cases identified presented with bilateral angle closure glaucoma and persistent elevated intraocular pressure despite patent iridotomy. Patients may be pseudophakic (2) or phakic (1). Cessation of the suspected medication is necessary to reverse the mechanism.

CONCLUSIONS

The proposed mechanism of angle closure glaucoma induced by sulphonamide medication involves an idiosyncratic reaction in the uveal tissues to these systemic drugs that is associated with expansion of the extracellular tissue of the ciliary body and choroid. Management identification of sulphonamide-derived medications and immediate cessation of suspected sulphonamide-derived medication, refraction and ultrasound B scan or ultrasound biomicroscopy may aid in the proper diagnosis and can also be helpful for confirmation.

Variables Contributing to Acute Mountain Sickness on the Summit of Mt Whitney☆

OBJECTIVE

The interaction of 15 variables representing physical characteristics, previous altitude exposure, and ascent data was analyzed to determine their contribution to acute mountain sickness (AMS).

METHODS

Questionnaires were obtained from 359 volunteers upon reaching the summit of Mt Whitney (4419 m). Heart rate and arterial oxygen saturation were measured with a pulse oximeter, and AMS was identified by Lake Louise Self-Assessment scoring. Multiple logistic regression analysis was used to identify significant protective and risk factors for AMS.

RESULTS

Thirty-three percent of the sample met the criteria for AMS. The odds of experiencing AMS were greater for those who reported a previous altitude illness (adjusted odds ratio [OR] = 2.00, P < .01) or who were taking analgesics during the ascent (adjusted OR = 2.09, P < .01). Odds for AMS decreased with increasing age (adjusted OR = 0.82, P < .0001), a greater number of climbs above 3000 m in the past month (adjusted OR = 0.92, P < .05), and use of acetazolamide during the ascent (adjusted OR = 0.33, P < .05).

CONCLUSIONS

The significant determinants of AMS on the summit of Mt Whitney were age, a history of altitude illness, number of climbs above 3000 m in the past month, and use of acetazolamide and analgesics during ascent.

Comparative efficacy of acetazolamide and apraclonidine in the control of intraocular pressure following phacoemulsification

PURPOSE

The purpose of our study was to compare the effects of systemically administered acetazolamide and topical apraclonidine 0.5% in the control of intraocular pressure (IOP) following phacoemulsification of senile cataracts.

SETTING

The study was conducted on patients affected by cataract and followed at the Department of Ophthalmology.

METHODS

Seventy-eight eyes in 78 patients were selected. Twenty-six eyes were randomly assigned to postoperative treatment with topical apraclonidine 0.5%, 26 received oral acetazolamide and the remaining 26 received no hypotensive treatment (control group). Statistical analyses were performed mainly by means of analyis of variance.

RESULTS

IOPs measured 24 h after surgery were significantly (p = 0.01) lower in the apraclonidine group compared to the control group.

CONCLUSIONS

Our double-blind prospective study conducted on patients randomly assigned to treatment with apraclonidine or acetazolamide shows that the former drug is undoubtedly effective in the prevention of IOP increases following phacoemulsification. IOPs recorded in patients treated with this drug were lower than those observed in the acetazolamide and the control groups. Considering the lower risk of toxicity associated with topical administration, apraclonidine 0.5% seems to be preferable to oral acetazolamide in this postoperative setting.

Effects of the selective cyclooxygenase-2 inhibitor analgesic celecoxib on renal carbonic anhydrase enzyme activity: a randomized, controlled trial

Rofecoxib and celecoxib were the first cyclooxygenase-2 (COX-2)-specific inhibitors to be marketed as effective anti inflammatory agents. The results of several recent trials and a meta analysis of currently available studies all demonstrate a greater incidence of increased blood pressure, edema, and cardiovascular events in subjects treated with rofecoxib compared with celecoxib. As an approach to the assessment of molecular mechanisms that may contribute to these cardiorenal differences, this study investigated the inhibitory effects of celecoxib on renal carbonic anhydrase enzyme activity in human hypertensive subjects because in vitro enzyme studies demonstrate such an effect. Ten subjects with stable, treated hypertension were randomized to 1 of 3 treatment sequences, which included, in differing order, 200 mg celecoxib twice a day, 250 mg acetazolamide twice a day, or placebo twice a day. Whereas acetazolamide caused a bicarbonate diuresis and a hyperchloremic metabolic acidosis, celecoxib appeared to have no detectable effect on renal carbonic anhydrase or acid-base homeostasis. Thus, in this short-term study of human subjects, therapeutic doses of celecoxib did not appear to have a clinically significant inhibitory action on renal carbonic anhydrase.

Stevens-Johnson Syndrome Associated With Intravenous Acetazolamide Administration for Evaluation of Cerebrovascular Reactivity-Case Report-

A 62-year-old man with left middle cerebral artery stenosis manifesting as transient ischemic attack underwent evaluation of regional cerebrovascular reactivity to acetazolamide using single photon emission computed tomography. Three days after intravenous administration of acetazolamide, erythematous eruptions of various sizes appeared on his back and spread over almost his entire body. Subsequently, painful ulcerations developed on his lips, and oral and nasal mucosa, and the conjunctiva became hyperemic, indicating Stevens-Johnson syndrome. The results of the lymphocyte transformation test were positive to only acetazolamide. Stevens-Johnson syndrome, also known as erythema multiforme major, can be life-threatening, and may be induced by intravenous administration of acetazolamide.

Preparation and evaluation of reverse-phase evaporation and multilamellar niosomes as ophthalmic carriers of acetazolamide

Niosomes have been reported as a possible approach to improve the low corneal penetration and bioavailability characteristics shown by conventional ophthalmic vehicles. Niosomes formed from Span 40 or Span 60 and cholesterol in the molar ratios of 7:4, 7:6 and 7:7 were prepared using reverse-phase evaporation and thin film hydration methods. The prepared systems were characterized for entrapment efficiency, size, shape and in vitro drug release. Stability studies were carried out to investigate the leaching of drug from niosomes during storage. The intraocular pressure (IOP) lowering activity of acetazolamide niosomal formulations in rabbits was measured using ShiØtz tonometer. Histological examination for the corneal tissues of rabbits receiving niosomal formulations was carried out for assessment of the ocular irritancy of niosomes. The results showed that the type of surfactant, cholesterol content and the method of preparation altered the entrapment efficiency and drug release rate from niosomes. Higher entrapment efficiency was obtained with multilamellar niosomes prepared from Span 60 and cholesterol in a 7:6 molar ratio. Niosomal formulations have shown a fairly high retention of acetazolamide inside the vesicles (approximately 75%) at a refrigerated temperature up to a period of 3 months. Each of the tested acetazolamide niosomes prepared by either method produced a significant decrease in IOP compared to the solution of free drug and plain niosomes. Multilamellar acetazolamide niosomes formulated with Span 60 and cholesterol in a 7:4 molar ratio were found to be the most effective and showed prolonged decrease in IOP. Histological examination of corneal tissues after instillation of niosomal formulation for 40 days showed slight irritation in the substantia propria of the eye which is reversible and no major changes in tissues were observed.

Adenosine A1 Receptor Antagonist Blunts Urinary Potassium Excretion, but Not Renal Hemodynamic Effects, Induced by Carbonic Anhydrase Inhibitor in Rats

Acetazolamide (AZ) is a carbonic anhydrase inhibitor with diuretic actions at the proximal tubule. Clinical use of AZ is limited, in part, because of the urinary potassium loss and decrease of renal hemodynamic function that accompanies the drug. There is recent interest in A1 adenosine receptor (A1AR) antagonists, a novel class of diuretic agents that do not cause loss of potassium or tubuloglomerular feedback- (TGF) mediated reductions of renal hemodynamics. We tested whether the A1AR antagonist 1,3-dipropyl-8-cyclopentylxanthine (DPCPX) could attenuate the adverse effects normally associated with use of AZ. Renal blood flow (RBF) and urine output were measured during two consecutive 40-min periods in anesthetized rats. In the first period, vehicle or DPCPX was infused. DPCPX alone increased urine output and sodium excretion but did not significantly alter potassium output or RBF. In the second period, the initial infusion of vehicle or DPCPX was continued, and either AZ or its vehicle was administered. AZ alone increased urinary excretion of both sodium and potassium and decreased RBF. DPCPX significantly attenuated the AZ-induced increase of potassium excretion by 50% but did not blunt the renal hemodynamic response to AZ. In a separate study, angiotensin II type 1 (AT1) receptor blockade also failed to blunt the renal hemodynamic response to AZ. In summary, A1AR antagonists may be useful diuretic agents alone or in combination with other conventional diuretic agents. The decrease of RBF that occurred in response to carbonic anhydrase inhibition was not attenuated by either A1AR blockade or AT1 receptor blockade and does not seem to be mediated by a TGF-dependent mechanism.

Glaucoma pharmacotherapy: implications for flying fitness

The objective of lowering the intraocular pressures remains the main-stay of therapy in the management of glaucoma, and may be achieved by medication, laser, or surgery. For many years the pharmacotherapy available, while quite effective, were few in number; principally timolol, pilocarpine, and oral acetazolamide. Through extensive research in glaucoma treatment, ophthalmologists now have access to a dozen different medications to treat glaucoma. This has invariably led to a decrease in the need for laser or surgery to control the intraocular pressures, and the number of glaucoma operations performed has progressively declined over the past few years. However, aviation medicine practitioners need to be aware of the potential adverse effects of these medications as some of these undesirable side effects may render the drugs unsuitable for aircrew.