The risk and management of kidney stones from the use of topiramate and zonisamide in migraine and idiopathic intracranial hypertension

Refractory uric acid nephrolithiasis dissolution using phentermine/topiramate: A case report

Uric acid is one of the few kidney stone minerals that can dissolve using oral alkalinization therapies such as potassium citrate. We report an obese female whose recalcitrant uric acid stones were eliminated using the weight loss medication phentermine/topiramate (Qsymia), a metabolic stimulant and carbonic anhydrase inhibitor. Pre- and post-dissolution 24-h urine studies and computed tomography images are included with a proposed mechanism of action of this medication. This is the first description of a non-alkaline oral therapy used alone for uric acid stone dissolution. Additional investigation of this medication in obese or diabetic uric acid stone formers is warranted.

Lamotrigine induced priapism in children: case analysis and literature review

Lamotrigine is an antiepileptic drug that can be used to control many types of seizures as a single-agent or an add-on therapy in patients over 2 years of age. In addition to common adverse reactions, this current case report describes a paediatric male patient with a rare side-effect of persistent penile erectile due to lamotrigine. Previous studies have shown that it can improve sexual function in adult male patients. This patient suffered from refractory epilepsy and pneumonia. He had taken a variety of antiepileptic drugs for a long time and developed priapism after the dosage of lamotrigine had been increased. The priapism improved after drug withdrawal and sedation. Further research is needed to elucidate the mechanism of this rare side-effect.

Urinary Metabolic Disturbances During Topiramate Use and their Reversibility Following Drug Cessation

OBJECTIVE

To understand the metabolic disturbances of stone formers currently taking topiramate and to examine the reversibility of these disturbances with cessation of the medication.

MATERIALS AND METHODS

All progress notes written by 5 endourologists from a single academic center were retrospectively reviewed from January 2010 to July 2020 containing the words "topiramate" or "topamax." Inclusion criteria were age > 18 and presence of either a 24-hour urine sample or stone analysis while on topiramate. In addition, a subgroup of 18 patients with 24-hour urine samples before and after stopping topiramate were identified.

RESULTS

A total of 93 patients were identified and included for final analysis. Twenty-four hour urine samples were available in 67 patients and showed mean citrate excretion of 331 ± 322 mg/day, mean pH of 6.6 ± 0.5, and mean calcium phosphate supersaturation of 1.9 ± 1.1. In the subgroup analysis urinary citrate excretion increased from 225 mg/day to 614 mg/day (p<0.01), pH decreased from 6.59 ± 0.54 to 6.33 ± 0.47 (p = 0.06). In addition, 114 stone events occurred in 73 distinct patients, with 50% of stones either pure or majority (≥ 50%) calcium phosphate by composition.

CONCLUSIONS

Hypocitraturia and elevated pH is seen during topiramate use with resultant higher rate of calcium phosphate stone formation compared to the general population. Stopping topiramate leads to significant increase in citrate excretion and normalization of pH. These metabolic disturbances appear to be reversible with medication cessation.

Symptomatic renal papillary varicosities and medullary nephrocalcinosis

Background

Nephrocalcinosis is often asymptomatic but can manifest with renal colic or hematuria. There is no reported association between nephrocalcinosis and renal vascular malformations, which may also be a source of hematuria. We herein present a case of a patient with hematuria related to nephrocalcinosis and renal papillary varicosities. These varicosities were diagnosed and successfully treated with flexible ureteroscopy and laser fulguration.

Case presentation

A 24-year-old female with a history of epilepsy (on zonisamide), recent uncomplicated pregnancy, and new diagnosis of nephrocalcinosis presented with right flank pain and intermittent gross hematuria. Imaging revealed intermittent right sided hydronephrosis. A cystoscopy identified hematuria from the right ureteral orifice. Diagnostic flexible ureteroscopy revealed numerous intrapapillary renal stones and varicose veins of several renal papillae. A 200 μm holmium laser fiber was used to unroof these stones and fulgurate the varicosities with resolution of her symptoms for several months. She later presented with left-sided symptoms and underwent left ureteroscopy with similar findings and identical successful treatment.

Conclusion

Unilateral hematuria from discrete vascular lesions of the renal collecting system may be obscured by other benign co-existing conditions, such as nephrocalcinosis and nephrolithiasis. Although a simultaneous presentation is rare, flexible ureteroscopy with laser fulguration offers an ideal diagnostic and therapeutic modality for these concurrent conditions if symptoms arise.

Association between kidney stones and risk of developing stroke: a meta-analysis

Background

Many studies have described the relationship between kidney stones and stroke, but the results are controversial, so we conducted this meta-analysis to estimate the relationship between kidney stones and the risk of developing stroke.

Methods

Studies were marked with a comprehensive search of PubMed, EMBASE, Google, and ISI Web of Science databases through 25 March 2020. Hazard ratios (HRs) and 95% confidence intervals (CIs) were extracted, and a random-effects model or fix-effects model was used to compute the pooled combined risk estimate. Heterogeneity was reported as I². We performed subgroup and sensitivity analysis to assess potential sources of heterogeneity.

Results

Eight studies of seven articles involving 3,526,808 participants were included in the meta-analysis. Overall, kidney stones were associated with a moderate risk of stroke incidence (HR, 1.24; 95% CI, 1.11–1.40; I²=79.6%; p=0.000). We conducted a sensitivity analysis by removing the studies that had a high risk of bias. Heterogeneity subsequently decreased significantly, while an increased risk of stroke in patient with kidney stones was again demonstrated (HR, 1.16; 95% CI, 1.11–1.23; I²=28.7%; p=0.000). Stratifying analysis showed that the results were more pronounced for ischemic stroke (HR, 1.14; 95% CI, 1.08–1.22; I²=15.6%; p=0.00) and the follow-up duration ≥10 years (HR, 1.18; 95% CI, 1.10–1.27; I²=31.6%; p=0.003).

Conclusions

Our meta-analysis suggests that patients with kidney stones may have a modestly increased risk of developing stroke, especially in ischemic stroke. More large-scaled and clinical trials should be done to identify the relative impact of kidney stones on stroke outcomes in the future.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10072-021-05113-5.

Pre-Clinical Assessment of the Nose-to-Brain Delivery of Zonisamide After Intranasal Administration

PURPOSE

Zonisamide clinical indications are expanding beyond the classic treatment of epileptic seizures to Parkinson's disease and other neurodegenerative diseases. However, the systemic safety profile of zonisamide may compromise its use as a first-line drug in any clinical condition. Since zonisamide is marketed as oral formulations, the present study aimed at exploring the potential of the intranasal route to centrally administer zonisamide, evaluating the systemic bioavailability of zonisamide and comparing its brain, lung and kidney pharmacokinetics after intranasal, oral and intravenous administrations.

METHODS

In vitro cell studies demonstrated that zonisamide and proposed thermoreversible gels did not affect the viability of RPMI 2650 or Calu-3 cells. Thereafter, male CD-1 mice were randomly administered with zonisamide by oral (80 mg/kg), intranasal or intravenous (16.7 mg/kg) route. At predefined time points, animals were sacrificed and plasma and tissues were collected to quantify zonisamide and describe its pharmacokinetics.

RESULTS

Intranasal route revealed a low absolute bioavailability (54.95%) but the highest value of the ratio between the area under the curve (AUC) between brain and plasma, suggesting lower systemic adverse events and non-inferior effects in central nervous system comparatively to intravenous and oral routes. Furthermore, drug targeting efficiency and direct transport percentage into the brain were 149.54% and 33.13%, respectively, corroborating that a significant fraction of zonisamide suffers direct nose-to-brain transport. Lung and kidney exposures obtained after intranasal administration were lower than those observed after intravenous injection.

CONCLUSIONS

This pre-clinical investigation demonstrates a direct nose-to-brain delivery of zonisamide, which may be a promising strategy for the treatment of central diseases.

Sulfamates in drug design and discovery: Pre-clinical and clinical investigations

In the present article, we reviewed the sulfamate-containing compounds reported as bioactive molecules. The possible molecular targets of sulfamate derivatives include steroid sulfatase enzyme, carbonic anhydrases, acyl transferase, and others. Sulfamate derivatives can help treat hormone-dependent tumors including breast, prostate, and endometrial cancers, Binge eating disorder, migraine, glaucoma, weight loss, and epilepsy. Sulfamate derivatives can act also as calcium sensing receptor agonists and can aid in osteoporosis. Furthermore, acyl sulfamate derivatives can act as antibacterial agents against Gram-positive bacteria. A recent study revealed a new side effect of topiramate, a sulfamate-containing compound, which is sialolithiasis. The structural and biological characteristics of the reviewed compounds are presented in detail.

The effect of antiepileptic drugs on the kidney function and structure

INTRODUCTION

Long-term use of antiepileptic drugs (AEDs) is associated with number of somatic conditions. Data from experimental, cross-sectional and prospective studies have evidence for the deleterious effect of some AEDs on the kidney. Areas covered: This review summarized the current knowledge of the effect of AEDs on the kidney including evidence and mechanisms. Fanconi syndrome was reported with valproate (VPA) therapy in severely disabled children with epilepsy. Renal tubular acidosis and urolithiasis were reported with acetazolamide, topirmate and zonisamide, drugs with carbonic anhydrase inhibition properties. Increased levels of urinary N-acetyl-beta-D-glucosaminidase (NAG) to urinary creatinine (U-NAG/UCr), urinary excretion of α1-micrglobulin, β-galactosidase activity; and urinary malondialdehyde to creatinine (MDA/Cr), markers of renal glomerular and tubular injury, were reported with chronic use of some AEDs (VPA, carbamazepine and phenytoin). The mechanism(s) of kidney dysfunction/injury induced by AEDs is unknown. Experimental and clinical studies have shown that VPA induces oxidative stress, mitochondrial deficits, carnitine deficiency and inflammation and fibrosis in renal tissue in mice and in vitro studies. Expert commentary: It seems reasonable to monitor kidney function during treating patients with epilepsy at high risk of kidney injury (e.g. on combined therapy with more than one AED, severely disabled children, etc).

Efficacy and Safety of Topiramate for Essential Tremor: A Meta-Analysis of Randomized Controlled Trials

Essential tremor (ET) is the most common movement disorder that is frequently treated by propranolol or primidone. However, 30% of patients with ET do not respond to either propranolol or primidone. The objective of this study was to assess the efficacy and safety of topiramate for ET.We searched the MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials for relevant randomized controlled trials on the effects of topiramate for ET. A meta-analysis technique was applied to estimate the efficacy and safety of topiramate. The primary outcome was the change in the Fahn-Tolosa-Marin tremor rating scale (TRS). The secondary outcomes included the respective change in the location, motor tasks/function and function disability scores, and adverse events.We included 3 randomized controlled trials with a total of 294 participants. Topiramate was significantly better than placebo in reducing TRS of patients with ET (mean difference [MD] -8.58, 95% confidence interval [CI] -15.46 to -1.70). Changes from the scales of upper limb tremor severity (MD -5.12, 95% CI -7.79 to -2.45), motor tasks/function (MD -5.07, 95% CI -7.12 to -3.03), and functional disability (MD -4.72, 95% CI -6.77 to -2.67) were significantly greater with topiramate than with placebo. More participants taking topiramate experienced adverse events leading to withdrawal than those taking placebo (risk difference 19%, 95% CI 11%-27%).There is consistent evidence supporting the efficacy of topiramate in treating ET; however, a significant proportion of participants withdrew due to its adverse effects.