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Ganguly A, Tyagi S, Chermansky C, Kanai A, Beckel J, Hashimoto M, Cho KJ, Chancellor M, Kaufman J, Yoshimura N, Tyagi P. Treating Lower Urinary Tract Symptoms in Older Adults: Intravesical Options. Drugs Aging 2023; 40:241-261. [PMID: 36879156 DOI: 10.1007/s40266-023-01009-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/26/2023] [Indexed: 03/08/2023]
Abstract
This article provides an overview of the diagnosis and the treatment of lower urinary tract symptoms in older adults complicated by the neurodegenerative changes in the micturition reflex and further confounded by age-related decline in hepatic and renal clearance raising the propensity of adverse drug reactions. The first-line drug treatment for lower urinary tract symptoms, orally administered antimuscarinics, fails to reach the equilibrium dissociation constant of muscarinic receptors even at their maximum plasma concentration and tends to evoke a half-maximal response at a muscarinic receptor occupancy of just 0.206% in the bladder with a minimal difference from exocrine glands, which raises the adverse drug reaction risk. On the contrary, intravesical antimuscarinics are instilled at concentrations 1000-fold higher than the oral maximum plasma concentration and the equilibrium dissociation constant erects a downhill concentration gradient that drives passive diffusion and achieves a mucosal concentration around ten-fold lower than the instilled concentration for a long-lasting occupation of muscarinic receptors in mucosa and sensory nerves. A high local concentration of antimuscarinics in the bladder triggers alternative mechanisms of action and is supposed to engage retrograde transport to nerve cell bodies for neuroplastic changes that underlie a long-lasting therapeutic effect, while an intrinsically lower systemic uptake of the intravesical route lowers the muscarinic receptor occupancy of exocrine glands to lower the adverse drug reaction relative to the oral route. Thus, the traditional pharmacokinetics and pharmacodynamics of oral treatment are upended by intravesical antimuscarinics to generate a dramatic improvement (~ 76%) noted in a meta-analysis of studies enrolling children with neurogenic lower urinary tract symptoms on the primary endpoint of maximum cystometric bladder capacity as well as the secondary endpoints of filling compliance and uninhibited detrusor contractions. The therapeutic success of intravesical multidose oxybutynin solution or oxybutynin entrapped in the polymer for sustained release in the pediatric population bodes well for patients with lower urinary tract symptoms at the other extreme of the age spectrum. Though generally used to predict oral drug absorption, Lipinski's rule of five can also explain the ten-fold lower systemic uptake from the bladder of positively charged trospium over oxybutynin, a tertiary amine. Chemodenervation by an intradetrusor injection of onabotulinumtoxinA is merited for patients with idiopathic overactive bladder discontinuing oral treatment because of a lack of efficacy. However, age-related peripheral neurodegeneration potentiates the adverse drug reaction risk of urinary retention that motivates the quest of liquid instillation, delivering larger fraction of onabotulinumtoxinA to the mucosa as opposed to muscle by an intradetrusor injection can also probe the neurogenic and myogenic predominance of idiopathic overactive bladder. Overall, the treatment paradigm of lower urinary tract symptoms in older adults should be tailored to individual's overall health status and the risk tolerance for adverse drug reactions.
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Affiliation(s)
- Anirban Ganguly
- Department of Urology, E313 Montefiore Hospital, University of Pittsburgh, 3459 Fifth Ave, Pittsburgh, PA, 15213, USA
| | - Shachi Tyagi
- Department of Medicine, University of Pittsburgh, 3459 Fifth Ave, Pittsburgh, PA, 15213, USA
| | - Christopher Chermansky
- Department of Urology, E313 Montefiore Hospital, University of Pittsburgh, 3459 Fifth Ave, Pittsburgh, PA, 15213, USA
| | - Anthony Kanai
- Department of Medicine, University of Pittsburgh, 3459 Fifth Ave, Pittsburgh, PA, 15213, USA
| | - Jonathan Beckel
- Department of Pharmacology, University of Pittsburgh, 3459 Fifth Ave, Pittsburgh, PA, 15213, USA
| | - Mamoru Hashimoto
- Department of Urology, E313 Montefiore Hospital, University of Pittsburgh, 3459 Fifth Ave, Pittsburgh, PA, 15213, USA
| | - Kang Jun Cho
- Department of Urology, E313 Montefiore Hospital, University of Pittsburgh, 3459 Fifth Ave, Pittsburgh, PA, 15213, USA
| | | | | | - Naoki Yoshimura
- Department of Urology, E313 Montefiore Hospital, University of Pittsburgh, 3459 Fifth Ave, Pittsburgh, PA, 15213, USA
| | - Pradeep Tyagi
- Department of Urology, E313 Montefiore Hospital, University of Pittsburgh, 3459 Fifth Ave, Pittsburgh, PA, 15213, USA.
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Shaker H, Mourad MS, Elbialy MH, Elhilali M. Urinary bladder hyperreflexia: a rat animal model. Neurourol Urodyn 2003; 22:693-8. [PMID: 14595617 DOI: 10.1002/nau.10147] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In this work, we are presenting a rat animal model for bladder hyperreflexia after suprasacral spinal cord transection. Our aim was to standardize an animal model that can be useful in studying this condition. After standardizing the animal model in a pilot study, 26 female Sprague-Dawley rats were subjected to spinal cord transection at the level of T10 vertebra. Four animals were subjected to cystometrogram (CMG) 24 hr after spinalization and six rats 3 weeks post-spinalization. These CMGs were compared to that of six normal controls. The detailed description of the model presented in this manuscript, is the final result after several modifications. All the animals consistently developed hyperreflexia after an initial period of spinal shock phase. Expressed volume of urine continued to decrease until it reached a plateau after peaking at 1-week post-spinalization. The attrition rate reached 27.3% after several improvements in the animal model and was mostly from self-inflicted injuries. Post-operative complications included hypothermia, decubitus ulcers, hematuria, urinary tract infection in addition to the unexplained death of two animals. In conclusion, we believe that this animal model closely resembles the clinical condition of hyperreflexia and follows similar course. The relative low cost of this animal model and the easy maintenance makes it a valuable tool to study such a condition.
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Affiliation(s)
- Hassan Shaker
- Urology Department, Ain Shams University, Cairo, Egypt.
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