Dihydropyridine calcium channel blockers and obstructive sleep apnea: Two underrecognized causes of nocturia?

Novel protocol for multiple-dose oral administration of the L-type Ca2+ channel blocker isradipine in mice: A dose-finding pharmacokinetic study

Studies in genetically modified animals and human genetics have recently provided new insight into the role of voltage-gated L-type Ca2+ channels in human disease. Therefore, the inhibition of L-type Ca2+ channels in vivo in wildtype and mutant mice by potent dihydropyridine (DHP) Ca2+ channel blockers serves as an important pharmacological tool. These drugs have a short plasma half-life in humans and especially in rodents and show high first-pass metabolism upon oral application. In the vast majority of in vivo studies, they have therefore been delivered through parenteral routes, mostly subcutaneously or intraperitoneally. High peak plasma concentrations of DHPs cause side effects, evident as DHP-induced aversive behaviors confounding the interpretation of behavioral readouts. Nevertheless, pharmacokinetic data measuring the exposure achieved with these applications are sparse. Moreover, parenteral injections require animal handling and can be associated with pain, discomfort and stress which could influence a variety of physiological processes, behavioral and other functional readouts. Here, we describe a noninvasive oral application of the DHP isradipine by training mice to quickly consume small volumes of flavored yogurt that can serve as drug vehicle. This procedure does not require animal handling, allows repeated drug application over several days and reproducibly achieves peak plasma concentrations over a wide range previously shown to be well-tolerated in humans. This protocol should facilitate ongoing nonclinical studies in mice exploring new indications for DHP Ca2+ channel blockers.

Nocturia and obstructive sleep apnoea

Nocturia, the need to urinate at night, is a common symptom in patients with obstructive sleep apnoea (OSA). Continuous positive airway pressure treatment can reduce nocturia in some patients, but the underlying mechanisms are complex and not fully understood. OSA affects the autonomic nervous system, oxidative stress and endothelial damage. Furthermore, the commonly held theory attributing polyuria to a false signal of cardiac overload and response natriuresis has limitations. A comprehensive approach to the management of nocturia in OSA, considering factors such as comorbidities, medication use, alcohol consumption and lifestyle, is needed. Effective management of nocturia in OSA requires a multidisciplinary approach, and urologists should be aware of the potential effect of OSA on physiology and refer patients for further testing at a sleep centre. In addition to continuous positive airway pressure, other interventions such as oral appliances and surgical obstruction treatment could be beneficial for some patients. Overall, understanding the complex interplay between OSA and nocturia is crucial for optimizing patient outcomes.

Calcium Channel Blockers Are Associated with Nocturia in Men Aged 40 Years or Older

BACKGROUND

The associations of nocturia with hypertension and anti-hypertensive agents (AHTs) remain to be validated.

METHODS

This cross-sectional study examined whether blood pressure and/or frequently used classes of AHTs had consistent associations with nocturia.

METHODS

A total of 418 male patients aged ≥ 40 years were retrospectively assessed in terms of the International Prostate Symptom Score (IPSS), prescription medications, and blood pressure. Nocturia was evaluated using item 7 of the IPSS, and two or more episodes of nocturia per night was considered to indicate clinically important nocturia.

RESULTS

Patients taking calcium channel blockers (CCBs), but not other AHTs, experienced more episodes of nocturia than patients not taking AHTs (1.77 ± 1.07, 1.90 ± 1.19, and 1.48 ± 0.98 in CCBs alone, CCBs + other AHTs, and other AHTs alone, vs. 1.35 ± 1.08 in not taking AHTs; p = 0.014, p < 0.0001, and p = 0.91, respectively), whereas there was no significant difference in the number of nocturia episodes between patients with elevated and normal blood pressure. In multivariate analysis, CCB (odds ratio (OR) = 2.68, p < 0.0001) and age (OR = 1.06, p < 0.0001) were independently associated with clinically important nocturia.

CONCLUSION

CCB was associated with nocturia, while AHTs other than CCBs and elevated blood pressure were not.