Intravenous patient-controlled analgesia hydromorphone combined with pregabalin for the treatment of postherpetic neuralgia: a multicenter, randomized controlled study.

BACKGROUND: Postherpetic neuralgia (PHN) is the most common complication of acute herpes zoster. The treatment of PHN remains a challenge for clinical pain management. Despite the effectiveness of anticonvulsants, antidepressants, and lidocaine patches in reducing PHN, many patients still face intractable pain disorders. In this randomized controlled study, we evaluated whether hydromorphone through intravenous patient-controlled analgesia (IV PCA) was effective in relieving PHN. METHODS: Patients with PHN were randomly divided into two groups, one group received oral pregabalin with IV normal saline, another group received oral pregabalin with additional IV PCA hydromorphone for two weeks. Efficacy was evaluated at 1, 4, and 12 weeks after the end of the treatments. RESULTS: Two hundred and one patients were followed up for 12 weeks. After treatment, numerical rating scale (NRS) score of patients in the hydromorphone group was significantly lower than that of the control group, and the difference of NRS scores between the two groups was statistically significant at 4 and 12 weeks after treatment. The frequency of breakthrough pain in the hydromorphone group was significantly lower than that in the control group 1 and 4 weeks after treatment. After treatment, the quality of sleep in the hydromorphone group was significantly improved compared with the control group. The most common adverse reactions in the hydromorphone group were dizziness and nausea, with no significant respiratory depression. CONCLUSIONS: IV PCA hydromorphone combined with oral pregabalin provides superior pain relief in patients with PHN, which is worthy of clinical application and promotion.

Characterizing ceftriaxone-induced urolithiasis and its associated acute kidney injury: an animal study and Chinese clinical systematic review.

OBJECTIVE: To investigate the pathophysiological process of ceftriaxone-induced urolithiasis and its associated acute kidney injury (AKI) based on an animal study and summarize the main clinical characteristics based on a Chinese clinical systematic review. MATERIALS AND METHODS: Male Sprague-Dawley rats were randomly divided into five groups of six each according to different treatments including control; ceftriaxone; ceftriaxone with calcium; calcium; and ceftriaxone, calcium with citrate, respectively. The 24-h urine volume, serum creatinine (Scr) and blood urea nitrogen (BUN) were measured; kidney histological examination and stone analysis were performed. Systematic searches of the Chinese Knowledge Database were conducted for reports on ceftriaxone-induced urolithiasis and AKI. The eligibility of each full-text publication was accessed, and qualified data were extracted and reviewed. RESULTS: Kidney stones and a significantly low 24-h urine volume with increased high Scr and BUN levels were found in the group that received ceftriaxone combined with calcium. Citrate was able to inhibit these biochemical changes and stone formations. A total of 161 qualified patients were included in the Chinese clinical systematic review: The proportion of ceftriaxone-induced urolithiasis was 21.1, 19.3, 19.3, 39.1 and 1.2 % for ages <3, 3-6, 7-17, 18-60 and >60 years. 72.7 % developed acute kidney injury eventually. CONCLUSION: Ceftriaxone-induced urolithiasis was associated with a high risk of AKI. The pathophysiological process may be related to urinary obstruction and crystalline nephropathy. Citrate was able to inhibit stone formation and prevent further kidney injury.

Possible function of urinary pH and citrate on the ceftriaxone-induced nephrolithiasis.

OBJECTIVE: To test whether urinary pH and citrate is associated with ceftriaxone-induced kidney stone formation and if acidified urine could dissolve this kind of stone using an in vitro crystallization model. METHODS: Crystallization was induced by mixing ceftriaxone at the standard therapeutic urinary concentration to artificial urine. The response of different physiological pH and citrate on ceftriaxone-induced crystallization was measured by the depletion ratio of ceftriaxone in the process. Compositions of formed crystals were qualitatively and quantitatively analyzed. The effect of acidifying urine on dissolving of ceftriaxone-induced crystal was determined by the surplus ratio of ceftriaxone in the process. RESULTS: Compositional analysis showed that ceftriaxone-induced crystals were composed of calcium and ceftriaxone with a ratio of 1:1. Compared to the response to pH 6.0, ceftriaxone-induced crystallizations in artificial urine at pH 4.5 and 5.0 for 4 hours were significantly decreased, and more acid urine resulted in less crystallization. However, it made no significant change when pH increased to 6.5 and 7.0. In addition, ceftriaxone-induced crystals formed at pH 6.0 for 4 hours could be dissolved significantly when artificial urine was acidified to pH 5.0 and 4.5 for 1, 2, and 4 hours; and more time of dissolution and more degree of acidifying resulted in more dissolution. CONCLUSION: Our study suggests that urinary pH and citrate are probable factors associated with ceftriaxone-induced nephrolithiasis. On one hand, alkaline urine and hypocitraturia predispose ceftriaxone nephrolithiasis, and vice versa. On the other hand, acidifying urine could dissolve ceftriaxone-induced stones.

Could infrared spectroscopy identify melamine-related stone using melamine-contained mixture as a reference?

BACKGROUND: Recently, a method of infrared spectroscopy analysis to identify melamine-contained stone was established by examining melamine powders mixed with true urinary stones. However, several studies demonstrated melamine could be interacted with cyanuric acid or uric acid in water through hydrogen bonds. It presents a hypothesis that the infrared spectrum of melamine-contained stone formed in urine is probably different from melamine-contained dry mixtures. This study is to testify is it true. METHODS: The melamine-related mixtures were, respectively, prepared by mixing powders of melamine with cyanuric acid or uric acid in equimolar ratio. The melamine-related precipitates mimicking its related stone formation were, respectively, prepared by mixing melamine with cyanuric acid or uric acid in water at the given conditions. Subsequently, the melamine-related mixtures and precipitates were analyzed by infrared spectroscopy. RESULTS: The wave-number positions of powder mixtures of melamine-cyanuric acid and melamine-uric acid were a combination of these of their individual ingredients. The typical wave-number positions of melamine were showed in two melamine-contained mixtures. In contrast, these positions were disappeared or shifted greatly in the two melamine-related precipitates. In total, the spectrum of precipitates of melamine with cyanuric acid and uric acid had significantly differences with their powder mixtures. CONCLUSIONS: Our results indicate the identification of melamine-related stone by infrared spectroscopy could not use the infrared spectrum of melamine-contained mixtures as a reference.

Comparison of renal function and metabolic abnormalities of cystine stone patients and calcium oxalate stone patients in China.

PURPOSE: To compare renal function and metabolic abnormalities of cystine stone patients and calcium oxalate stone patients in China. METHODS: Between 2008 and 2011, thirty cystine stone patients were involved in our study, and an equal number of age- and gender pair-matched patients with calcium oxalate stones. Non-stone forming individuals were elected as controls. The evaluation included blood chemistry studies and 24-h urine collection in both groups of patients. RESULTS: The cystine stone patients had higher mean values of serum blood urea nitrogen, urate and creatinine levels than patients in other two groups. With respect to urine risk factors, cystine stone patients had higher urinary citrate and lower urinary oxalate and creatinine than calcium oxalate stone patients. When compared to non-stone forming individuals, cystine stone patients had higher urinary urate excretion and lower urinary creatinine excretion. Metabolic abnormalities could be demonstrated in 80 % of the cystine stone patients and in 100 % of the calcium oxalate stone patients. We also compared urine risk factors among cystine stone patients with different urine cystine excretion (<1 mmol/24 h, 1-2 mmol/24 h and >2 mmol/24 h). No significant difference was found in urine risk factors among three groups. CONCLUSIONS: This study suggested that cystine stone patients were at greater risk for the loss of renal function than calcium oxalate stone patients, but the risk of the formation of calcium oxalate stones was lower. Our results also indicated that urinary cystine had little or no impact on the excretion of urine chemistries in cystine stone patients.