sildenafil-citrate and Fatigue

Acute mountain sickness (AMS) is a common problem among visitors at high altitude, and may progress to life-threatening pulmonary and cerebral oedema in a minority of cases. International consensus defines AMS as a constellation of subjective, non-specific symptoms. Specifically, headache, sleep disturbance, fatigue and dizziness are given equal diagnostic weighting. Different pathophysiological mechanisms are now thought to underlie headache and sleep disturbance during acute exposure to high altitude. Hence, these symptoms may not belong together as a single syndrome. Using a novel visual analogue scale (VAS), we sought to undertake a systematic exploration of the symptomatology of AMS using an unbiased, data-driven approach originally designed for analysis of gene expression. Symptom scores were collected from 292 subjects during 1110 subject-days at altitudes between 3650 m and 5200 m on Apex expeditions to Bolivia and Kilimanjaro. Three distinct patterns of symptoms were consistently identified. Although fatigue is a ubiquitous finding, sleep disturbance and headache are each commonly reported without the other. The commonest pattern of symptoms was sleep disturbance and fatigue, with little or no headache. In subjects reporting severe headache, 40% did not report sleep disturbance. Sleep disturbance correlates poorly with other symptoms of AMS (Mean Spearman correlation 0.25). These results challenge the accepted paradigm that AMS is a single disease process and describe at least two distinct syndromes following acute ascent to high altitude. This approach to analysing symptom patterns has potential utility in other clinical syndromes.

Topics: Acute Disease; Adult; Altitude; Altitude Sickness; Antioxidants; Bolivia; Expeditions; Fatigue; Female; Headache; Humans; Male; Mountaineering; Piperazines; Purines; Severity of Illness Index; Sildenafil Citrate; Sleep Wake Disorders; Sulfones; Surveys and Questionnaires; Syndrome; Tanzania; Vasodilator Agents; Visual Analog Scale; Young Adult

Topics: Benzhydryl Compounds; COVID-19; Dyspnea; Fatigue; Glucosides; Humans; Sildenafil Citrate

A young male patient reported for evaluation of progressive easy fatigability, accompanied by a recent history of recurrent haemoptysis. His clinical examination was unremarkable except for evidence of pulmonary arterial hypertension (PAH). Routine investigations (haemogram, coagulogram, serological tests for connective tissue disorders and a sputum Ziehl Neelsen stain for acid-fast bacilli) were normal. Two-dimensional echocardiography suggested PAH (pulmonary artery systolic pressure-67 mm Hg), whereas the 64-slice spiral CT pulmonary angiogram showed a dilated main pulmonary artery along with bilateral arteriovenous malformations. Cardiac catheterisation performed subsequently confirmed the presence of PAH. On the basis of the above findings, a diagnosis of hereditary haemorrhagic telangiectasia (HHT) complicated with PAH was made, and the patient was started on oral sildenafil therapy to which he responded well. This rare complication of HHT, which requires a high degree of suspicion for diagnosis, is discussed.

Topics: Echocardiography; Familial Primary Pulmonary Hypertension; Fatigue; Hemoptysis; Humans; Hypertension, Pulmonary; Male; Piperazines; Purines; Sildenafil Citrate; Sulfones; Telangiectasia, Hereditary Hemorrhagic; Tomography, X-Ray Computed; Vasodilator Agents; Young Adult

Sildenafil is a selective inhibitor of phosphodiesterase type 5 (PDE-5). Its chronic administration has been shown to improve exercise capacity, World Health Organization functional class, and haemodynamics in patients with symptomatic pulmonary arterial hypertension (PAH). There is however, no data describing the clinical consequences of sudden cessation of sildenafil treatment. In this series, 9 patients with NYHA Class II-IV PAH who were stable on 2 months of sildenafil monotherapy, had their sildenafil ceased to accommodate a 2-week washout period, required for enrollment in research involving an endothelin receptor antagonist. Six minute walk distance (SMWD) and clinical assessments were performed before cessation of sildenafil, and again 2 weeks later. Over the course of this 2-week washout period, 6 of the 9 patients reported increased breathlessness and fatigue, 1 of these was hospitalized with worsening right heart failure. The SMWD fell in 6 patients, with falls of greater than 100 m recorded in 4 patients. This was accompanied by a worsening of NYHA Class from 2.5 +/- 0.2 to 3.1 +/- 0.1 (mean +/- SEM, p = 0.01). These data indicate that sudden cessation of sildenafil monotherapy, in patients with PAH, carries with it a significant and unpredictable risk of rapid clinical deterioration. We recommend that if sildenafil needs to be ceased, it would be more prudent to consider concurrent vasodilator therapy before the gradual cessation of sildenafil.

Topics: Adult; Disease Progression; Drug Administration Schedule; Exercise Tolerance; Fatigue; Female; Heart Failure; Humans; Hypertension, Pulmonary; Male; Middle Aged; Phosphodiesterase Inhibitors; Piperazines; Purines; Respiration; Sildenafil Citrate; Sulfones; Treatment Outcome; Vasodilator Agents; Withholding Treatment

Sildenafil, a phosphodiesterase-5 inhibitor is widely used for the treatment of erectile dysfunction. Recently, the FDA approved the use of sildenafil in the therapeutic treatment of pulmonary arterial hypertension. Sildenafil crosses the blood-brain barrier and has been shown to enhance memory. Tremor, rigidity and akinesia are the most common symptoms seen in Parkinson's disease. Fatigue and sexual dysfunction are the other prominent features seen in Parkinson's disease. Interestingly, sildenafil is used therapeutically to treat sexual dysfunction in Parkinson's disease patients. Currently research on Parkinson's disease focuses on developing novel drug therapies for retarding the nigral dopaminergic neurodegeneration. Hence, we investigated the anti-fatigue and neuroprotective effects of sildenafil. In this study, the effect of sildenafil on fatigue was evaluated using forced swim test in mice. Sildenafil had no effect on fatigue as seen by the swim time. With regard to neuroprotective effects, we investigated the effects of sildenafil using two animal models of Parkinson's disease. In this study, 6-hydroxydopamine-lesioned (unilateral) rats and MPTP-treated mice were used as the animal models of Parkinson's disease. 6-Hydroxydopamine-lesioned rats were used to determine the effect of sildenafil on rotational behavior. Ipsilateral or contralateral rotational behavior can indicate the amphetamine-like activity or apomorphine-like activity of sildenafil. Sildenafil did not induce contralateral or ipsilateral rotations in 6-hydroxydopamine-lesioned rats. Sildenafil did not protect against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced dopamine depletion in the striatum.

Topics: Animals; Fatigue; Male; Mice; Mice, Inbred C57BL; MPTP Poisoning; Neuroprotective Agents; Oxidopamine; Phosphodiesterase Inhibitors; Piperazines; Purines; Sildenafil Citrate; Sulfones