• 한국임상약학회지
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• 제30권1호
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• pp.59-64
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• 2020

The emergence of phosphodiesterase (PDE) 5 inhibitors gave rise to the solution for erectile dysfunction, starting with the development of sildenafil. Although their efficacy in treating erectile dysfunction has been shown, the side effects of PDE5 inhibitors, especially sildenafil, must be taken into consideration. A 64-year-old man received 100 mg of sildenafil and experienced blue vision in both eyes; however, after a day or so, his symptoms improved. The symptoms disappeared when he stopped administering sildenafil, but reappeared when the medication was re-administered. Therefore, he discontinued sildenafil treatment and was prescribed udenafil instead. After that, visual adverse events no longer occurred. Causality assessment showed that in this case, sildenafil-induced cyanopsia was "certain" under the World Health Organization-Uppsala Monitoring Center (WHO-UMC) criteria and Korean causality assessment algorithm (Ver.2), and was "probable" according to the Naranjo scale. In addition, sildenafil also led to abnormal visual reactions in other cases. Sildenafil can also inhibit PDE6, which is present in retinal cells, unlike other PDE5 inhibitors. Thus, visual adverse reactions, such as blue vision, are the unique results of sildenafil, and other PDE5 inhibitors may be used to prevent them.

• Biotechnology and Bioprocess Engineering:BBE
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• 제11권5호
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• pp.402-407
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• 2006

Vascular endothelial cells release proteinases that degrade the extracellular matrix (ECM), thus enabling cell migration during angiogenesis and vasculogenesis. Sildenafil citrate stimulates the nitric oxide-cyclic guanosine monophosphate pathway through inhibition of phosphodiesterase type V (PDE5). In this report, we examined the mechanisms underlying sildenafil citrate-induced cell migration using cultured mouse aortic endothelial cells (MAECs). Sildenafil citrate induced migration and proteinase secretion by murine endothelial cells. Sildenafil citrate induced the secretion of matrix metalloproteinase-2 (MMP-2) and MMP-9, which is inhibited by $NF-{\kappa}B$ inhibitors. Sildenafil citrate also induced the secretion of plasmin, which is inhibited by PI 3'-kinase inhibitors. It is suggested that sildenafil citrate-induced migrating activity in endothelial cells may be accomplished by increased secretion of proteinases.

• Journal of Pharmaceutical Investigation
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• 제41권4호
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• pp.249-253
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• 2011

To develop a sildenafil lactate-loaded solid self-emulsifying drug delivery system (SEDDS) with a fast onset of action and immediate action of erection, sildenafil lactate (0.3 g), which was prepared using a spray dryer, was dissolved in 4.7 g of the mixture of glyceryl monooleate/Transcutol/ Tween 20 (3/0.5/1, g). Its emulsion droplet size and pharmacokinetics in rabbits were evaluated compared with sildenafil citrate-loaded commercial tablet. The sildenafil lactateloaded SEDDS showed an emulsion droplet size of about 300 nm. In pharmacokinetics study, it gave significantly faster Tmax than did the commercial tablet. Thus, the sildenafil lactate-loaded SEDDS at the one-third drug dose compared to sildenafil citrate-loaded conventional tablet might induce a fast onset of action and immediate erection without enhanced bioavailability compared with the sildenafil citrate-loaded commercial tablet.

• Neonatal Medicine
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• 제18권1호
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• pp.124-129
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• 2011

목적: 최근 PPHN의 치료를 위해 iNO와 함께 많은 약물적 치료가 사용되고 있다. Sildenafil은 PDE5의 억제제로 선택적인 폐혈관 확장제로 알려져 있으며 iNO에 비하여 접근성이 뛰어나 iNO에 대안적인 약제로 연구되어 왔다. 저자들은 본원에서 sildenafil로 PPHN을 치료한 경험을 분석하였다. 방법: 심초음파를 통해 PPHN으로 진단된 재태 기간 35주 이상, FiO2 1.0을 필요로 하는 32명의 환아를 대상으로 하였으며 의무기록을 후향적으로 조사하였다. sildenafil은 0.5 mg/kg로 시작하여 6시간마다 1 mg/kg로 투약하였으며, 투약 전과 후 6, 12, 24, 48시간의 MAP, $FiO_2$, OI, MBP를 비교하였다. 부작용을 확인하기 위하여 환아들의 위장관 증상, 뇌초음파, 안저검사와 청성뇌간유발반응 검사의 결과를 조사하였다. 결과: 대상 환아 32명 중 태변 흡인 증후군 9명, 호흡곤란증후군 8명, 폐렴 3명이었으며, 12명은 특발성이었다. 이 중 31명이 생존하였으며 28명의 환아는 본원에서 sildenafil만으로 치료되었고 3명의 환아는 전원되어 iNO 치료 후 회복하였다. Sildenafil 단독으로 치료된 28명의 환아에서 $FiO_2$와 OI는 치료 6시간째부터 MAP는 48시간째부터 유의하게 감소하였다. 모든 환아에서 특별한 부작용은 관찰되지 않았다. 결론: Sildenafil은 35주 이상의 PPHN 환아에서 비교적 효과적이고 안전하게 시도해 볼 수 있는 대안 약제로서, 특히 iNO가 가능하지 않은 병원에서 유용할 것으로 생각된다.

• The Korean Journal of Pain
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• 제20권1호
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• pp.21-25
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• 2007

Background: Intrathecal sildenafil has produced antinociception by increasing the cGMP through inhibition of phosphodiesterase 5. Spinal opioid receptor has been reported to be involved in the modulation of nociceptive transmission. The aim of this study was to examine the role of opioid receptor in the effect of sildenafil on the nociception evoked by formalin injection. Methods: Rats were implanted with lumbar intrathecal catheters. Formalin testing was used as a nociceptive model. Formalin-induced nociceptive behavior (flinching response) was observed. To clarify the role of the opioid receptor for the analgesic action of sildenafil, naloxone was administered intrathecally 10 min before sildenafil delivery, and formalin was then injected 10 min later. Results: Intrathecal sildenafil produced dose-dependent suppression of flinches in both phases during the formalin test. Intrathecal naloxone reversed the analgesic effect of sildenafil in both phases. Conclusions: Sildenafil is active against the nociceptive state that's evoked by a formalin stimulus, and the opioid receptor is involved in the analgesic action of sildenafil at thespinal level.

• The Korean Journal of Pain
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• 제20권2호
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• pp.106-110
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• 2007

Background: A phosphodiesterase 5 inhibitor, sildenafil, has been effective against nociception. Several lines of evidence have demonstrated the role of the GABAergic pathway in the modulation of nociception. The impact of the GABA receptors on sildenafil was studied using the formalin test at the spinal level. Methods: Male SD rats were prepared for intrathecal catheterization. The formalin test was induced by subcutaneous injection of formalin solution. The change in the activity of sildenafil was examined after pre-treatment with GABA receptor antagonists ($GABA_A$ receptor antagonist, bicuculline; $GABA_B$ receptor antagonist, saclofen). Results: Intrathecal sildenafil dose-dependently attenuated the flinching observed during phase 1 and 2 in the formalin test. The antinociceptive effect of sildenafil was reversed by the $GABA_B$ receptor antagonist (saclofen) but not by the $GABA_A$ receptor antagonist (bicuculline) in both phases. Conclusions: Intrathecal sildenafil suppressed acute pain and the facilitated pain state. The antinociception of sildenafil is mediated via the $GABA_B$ receptor, but not the $GABA_A$ receptor, at the spinal level.

• The Korean Journal of Pain
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• 제19권1호
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• pp.17-21
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• 2006

Background: Cyclic guanosine monophosphate (cGMP) plays an important role in the modulation of nociception. Although local sildenafil produces antinociception, by increasing cGMP through the inhibition of phosphodiesterase 5, the effect of spinal sildenafil has not been determined. The authors evaluated the effects of intrathecal sildenafil on the nociceptive behavior evoked by formalin injection and thermal stimulation. Methods: Lumbar intrathecal catheters were implanted into rats, with formalin and Hot-Box tests used as nociceptive models. The formalin-induced nociceptive behavior (flinching response) and withdrawal latency to radiant heat were measured, and the general behaviors also observed. Results: The intrathecal administration of sildenafil produced dose-dependent suppression of the flinches in both phases in the formalin test, and increased the withdrawal latency in the Hot-Box test. No abnormal behaviors were noted. Conclusions: Sildenafil, an inhibitor of phosphodiesterase 5, is active against the nociceptive state evoked in the spinal cord by formalin and thermal stimulations. Accordingly, spinal sildenafil may be useful in the management of pain.

• 대한두개안면성형외과학회지
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• 제16권2호
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• pp.73-79
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• 2015

Background: Alprostadil and sildenafil are known vasodilators used independently to improve flap survival in animal models. In this study, we investigate whether these agents act synergistically to decrease flap necrosis in rat models. Methods: After acclimation period, 4 groups of 10 male white rats were given a modified McFarlane skin flap. The postoperative treatment included saline control (Group A), sildenafil citrate-only (Group B), alprostadil-only (Group C), and both sildenafil and alprostadil (Group D). The flaps were observed on postoperative days 1, 3, 5 and 7. The animals were euthenized on postoperative day 7, and the flaps were evaluated for inflammation and neovascularization. Results: At each observation, the mean necrotic index was significantly lower for all three treatment groups (Groups A, B, C) and was the lowest for the combined treatment group. On histologic evaluations, combined treatment was associated with decreased inflammation and increased capillary vessel formation, when compared with control group. Conclusion: Both sildenafil-only and alprostadil treatments were independently associated with increased flap survival rate. Sildenafil citrate and alprostadil had a synergistic effect in increasing flap survival rate.

• Journal of Yeungnam Medical Science
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• 제39권3호
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• pp.262-265
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• 2022

Penile Mondor disease (MD) is a palpable, painful, subcutaneous induration caused by superficial dorsal penile vein thrombosis. We report a case of penile MD that was suspected to be related to prolonged oral sildenafil use. A 46-year-old man visited our emergency department with sustained penile pain and swelling that began 7 hours after sexual intercourse. He had used oral sildenafil intermittently for 11 years and engaged in sexual intercourse the previous night after taking sildenafil. Examination revealed no evidence of intercourse-related trauma to the genital area or an increase in penile skin temperature. However, penile swelling and tenderness over the protruding dorsal penile vein were noted. A color Doppler ultrasound examination was performed immediately, which showed hyperechoic thrombosis in the right superficial dorsal penile vein that was dilated, with soft tissue swelling and no detectable flow signal in the thrombotic lesion. The patient was diagnosed as having penile MD. The patient was treated conservatively. Some reports have indicated the involvement of sildenafil in thrombogenesis. Physicians should be aware that prolonged oral sildenafil use may be associated with penile MD.

• Translational and Clinical Pharmacology
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• 제25권3호
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• pp.153-156
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• 2017

UI14SDF100CW is a chewable tablet of sildenafil citrate, which was developed to improve compliance through convenience of administration. The purpose of this study was to compare the pharmacokinetic (PK) properties of sildenafil citrate chewable tablets (UI14SDF100CW) and conventional sildenafil citrate film-coated tablets ($Viagra^{(R)}$, Pfizer). A randomized, open-label, single dose, two-treatment, two-period, two-way crossover study was conducted in 60 healthy male volunteers. In each period, the subjects received a single oral dose of UI14SDF100CW or $Viagra^{(R)}$ (both tablets contain 140.45 mg of sildenafil citrate, which is equivalent to 100 mg of sildenafil). Serial blood samples were collected up to 24 h post-dose for PK analysis. The plasma concentration of sildenafil was determined using a validated HPLC-MS/MS assay. PK parameters of sildenafil were calculated using non-compartmental methods. The plasma concentration-time profiles of sildenafil in both formulations were similar. For UI14SDF100CW, the $C_{max}$ and $AUC_{last}$ of sildenafil were $1068.69{\pm}458.25$ (mean${\pm}$standard deviation) mg/L and $3580.59{\pm}1680.29h{\cdot}mg/L$, and the corresponding values for $Viagra^{(R)}$ were $1146.84{\pm}501.70mg/L$ and $3406.35{\pm}1452.31h{\cdot}mg/L$, respectively. The geometric mean ratios (90% confidence intervals) of UI14SDF100CW to $Viagra^{(R)}$ for $C_{max}$ and $AUC_{last}$ were 0.933 (0.853-1.021) and 1.034 (0.969-1.108), respectively, which met the bioequivalence criteria of Korean regulatory agency. In conclusion, UI14SDF100CW and $Viagra^{(R)}$ showed similar PK properties. Therefore, UI14SDF100CW can be an alternative to sildenafil for the treatment of erectile dysfunction, providing better compliance.