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Query: UMLS:C0018681 (headache)
 56,091 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The objective of this study was to assess the efficacy and safety of sildenafil citrate (Viagra) in black American and Hispanic American men with erectile dysfunction (ED) of broad-spectrum etiology. A total of 246 black American and 197 Hispanic American men were randomized to sildenafil (50 mg, adjustable to 25 mg or 100 mg, depending on efficacy and tolerability; n = 124 and n = 99, respectively) or matching placebo (n = 122 and n = 98, respectively). After 6 weeks, patients were given the option of switching to the other blinded treatment for the following 6 weeks. The 12 weeks of double-blind treatment were followed by 12 weeks of open-label extension. Despite differences in prevalence of hypertension, diabetes mellitus, hyperlipidemia, and use of concomitant antihypertensive agents between the 2 study groups, sildenafil was efficacious and well tolerated. After 6 weeks, scores for questions 3 and 4 from the International Index of Erectile Function (IIEF) were significantly higher among sildenafil-treated black and Hispanic patients than in placebo-treated patients. In addition, compared with placebo, a significantly larger proportion of sildenafil patients reported improved erections and improved ability to have sexual intercourse. When efficacy results were stratified by ED severity or number of risk factors, scores for IIEF questions 3 and 4 were lower in men with severe ED versus mild-to-moderate ED. Similarly, the percentage of patients reporting improved erections decreased with ED severity and number of risk factors. The proportion of patients switching to the other treatment after 6 weeks was significantly higher in the placebo group (71% to 85%) than in the sildenafil group (27% to 28%). The most common adverse events included headache and vasodilation, which were mild to moderate in nature and were comparable between groups. These data demonstrate that despite differences in prevalence rates of comorbidities, efficacy and safety of sildenafil is maintained across different ethnic groups.
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PMID:Efficacy and safety of sildenafil citrate (Viagra) in black and Hispanic American men. 1241 32

Migraine is considered a neurovascular disease involving dilatation of cerebral arteries. Nitric oxide (NO) donors induce dilatation of cerebral and extracranial arteries and migraine, but NO has several mechanisms of action in addition to its cyclic guanosine monophosphate (cGMP)-mediated vasodilatation. We examined whether sildenafil (Viagra), a selective inhibitor of cGMP-hydrolysing phosphodiesterase 5 (PDE5), which acts exclusively by increasing cGMP, can induce migraine and dilatation of cerebral arteries. We included 12 patients with migraine without aura in this double-blind, placebo-controlled crossover study, in which placebo or sildenafil 100 mg was administered orally on two separate days. Blood flow velocity in the middle cerebral artery (V(mca)) was recorded by transcranial Doppler ultrasonography and regional cerebral blood flow in the territory of the middle cerebral artery (rCBF(mca)) was measured using SPECT (single photon emission computed tomography) and xenon 133 inhalation. Radial and temporal artery diameters were studied using high-frequency ultrasonography. Headache response, tenderness of pericranial muscles, blood pressure and heart rate were measured repeatedly. We found that migraine attack was induced by sildenafil in 10 of 12 migraine patients and by placebo in two of 12 patients (P = 0.01). V(mca) (P = 0.1) and rCBF(mca) (P = 0.93) remained unchanged after sildenafil. Temporal (P = 0.47) and radial (P = 0.87) artery diameter and pericranial tenderness (P = 0.16) were unaffected by sildenafil. Systolic and diastolic blood pressures were unchanged but heart rate increased from a mean of 62 +/- 2 to 74 +/- 3 beats/min (P = 0.01) after sildenafil. Our results demonstrate that migraine may be induced via a cGMP-dependent mechanism, and we show for the first time that this occurs without initial dilatation of the middle cerebral artery. We propose that triggering mechanisms may reside within the perivascular sensory nerve terminals or the brainstem. However, other sites of action may also be possible and future studies are needed to elucidate this. In the clinical use of sildenafil, patients who have migraine should be informed about the risk of migraine attacks.
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PMID:Migraine can be induced by sildenafil without changes in middle cerebral artery diameter. 1247 10

The treatment of erectile dysfunction (ED) has been revolutionised by new agents to inhibit the enzyme PDE5. The scientific basis of this treatment of ED includes relaxation of the corpus cavernosum smooth muscle tissue by inhibition of PDE5 that breaks down cGMP, the key pathway for the production of erectile function in humans. Many clinical studies, both pre- and post-marketing, have demonstrated the clinical efficacy and safety of sildenafil (Viagra, Pfizer) - the first approved selective PDE inhibitor for the treatment of ED. Sildenafil is inhibitory of PDE5 at a rate tenfold higher than for the next PDE (PDE6), which produces visual changes through the retinal rods. Its clinical effectiveness has been well documented in the majority of men with ED irrespective of aetiology. The aetiology of ED, also, does not appear to effect the function of sildenafil in relaxing corpus cavernosum smooth muscle tissue. Adverse events are usually associated with the vascular changes from PDE5 inhibition. These include headache and flushing. Each of these adverse events, however, declines with medication use. With the use of sildenafil, it has been clearly, clinically demonstrated that the selective inhibition of PDE5 is an appropriate, effective, safe method for the treatment of ED of all aetiologies and severities.
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PMID:Long-term use of sildenafil. 1261 92

Fifty-eight Nigerian outpatients with documented erectile dysfunction (ED) received open-label sildenafil citrate (Viagra) for 8 weeks. The 50-mg starting dose could be adjusted to 100 or 25 mg based on response and tolerability. The International Index of Erectile Function (IIEF) Questionnaire, a global efficacy question, and intercourse data recorded in a patient event log were used to assess efficacy. Frequency of penetration and maintained erection were both significantly enhanced (P<0.0001); 95% of patients reported improved erections and 81% of all attempts at intercourse were successful. Orgasmic function, sexual desire, intercourse satisfaction, and overall satisfaction also improved significantly (P&<0.0001). The most frequent adverse events (all-cause) were headache (17%) and myalgia (3%); only one patient discontinued treatment because of headache, which was considered unrelated to sildenafil. Oral sildenafil significantly improved erectile function and was well tolerated in this trial of Nigerian men suffering from ED. Our results are consistent with reports from other countries.
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PMID:Sildenafil citrate (Viagra) for the treatment of erectile dysfunction in Nigerian men. 1282 4

The efficacy of sildenafil citrate (Viagra), an oral agent for the treatment of erectile dysfunction (ED), has been demonstrated in global studies. This 12-week randomized, double-blind, placebo-controlled, parallel-group, flexible-dose study assessed the efficacy and safety of sildenafil to treat ED in men in Egypt and South Africa. Men with ED of varied etiology were randomized to receive sildenafil 50 mg (n=128) or placebo (n=126); doses could be adjusted to 100 or 25 mg. Questions from the International Index of Erectile Function (IIEF) assessing the ability to achieve (Q3) and maintain (Q4) erections demonstrated a significant improvement with sildenafil compared with placebo (P<0.0001). Improved erections were reported by 74% of patients receiving sildenafil and 27% of those receiving placebo (P<0.0001). Headache, dyspepsia, and flushing were the most common adverse events in sildenafil-treated patients. These results are consistent with clinical trials in other countries. We conclude that sildenafil is an efficacious and well-tolerated treatment for men with ED in Egypt and South Africa.
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PMID:Efficacy and safety of sildenafil citrate (Viagra) for the treatment of erectile dysfunction in men in Egypt and South Africa. 1282 6

Sildenafil (Viagra), a selective inhibitor of phosphodiesterase 5 (PDE5), induces headache and migraine. Although previously supposed to be a "vascular" headache, no significant cerebral artery dilatation was found in vivo. Thus, we hypothesised that PDE5 may not be present or that sildenafil is less effective on the cGMP hydrolysis in cerebral arteries, and that sildenafil may not be an effective dilator of cerebral arteries under baseline conditions. We evaluated the presence of PDE5 mRNA and protein in human arteries. Furthermore, the effects of two selective PDE5 inhibitors, sildenafil and UK-114,542, and a PDE1 inhibitor UK-90,234 on cGMP hydrolysis were investigated in human and guinea pig cerebral arteries. The vasoactive responses of the compounds were evaluated in guinea pig basilar arteries in vitro, with concomitant measurements of cAMP and cGMP. PDE5 was found in human middle cerebral arteries. Sildenafil and UK-114,542 inhibited cGMP hydrolysis concentration-dependently in both species. In guinea pig arteries, sildenafil induced an endothelium-dependent vasodilatation only at concentrations above 10 nM, which was augmented by sodium nitroprusside and attenuated by reduction of cGMP, but was cGMP independent at high concentrations. UK-114,542 was more and UK-90,234 was less potent than sildenafil. In conclusion, PDE5 is present in human and guinea pig cerebral arteries, and is inhibited by sildenafil at micromolar levels. Sildenafil in vitro is a poor dilator of guinea pig cerebral arteries unless a nitric oxide donor is co-administered, corresponding to the previous findings in vivo.
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PMID:Phosphodiesterase 5 and effects of sildenafil on cerebral arteries of man and guinea pig. 1618 82

Sildenafil (Viagra) is a selective phosphodiesterase type 5 inhibitor (PDE5-I) approved for treatment of erectile dysfunction. Although relatively well-tolerated, sildenafil is associated with undesired effects including headache, flushing, dyspepsia, nasal congestion, and visual disturbances. In the present study we explored the impact of sildenafil on nasal airway parameters in young potent men. Eleven men (age 26.0 +/- 1.8 years) with normal BMI (25.7 +/- 0.5) and without nasal respiratory disorders were enrolled in a double-blind, crossover study. All men underwent evaluation of systolic (SBP) and diastolic blood pressure (DBP), heart rate (HR), SpO2%, acoustic rhinometry, and nasal endoscopy before and after placebo or sildenafil (50 mg) plus visual sexual stimulation (VSS). Nasal examination was performed using 0 degrees rigid telescopes, 4 mm in diameter. A Student's t test was used for direct comparisons, while the Kruskal-Wallis test (K-W) was utilized for multiple comparisons. After administration of sildenafil plus VSS, the minimum cross sectional area (MCA) was significantly lower that observed with either placebo (P = 0.03) or sildenafil alone (P = 0.003). However, the post-stimulation values did not demonstrate any significant differences among the different treatment arms (P = 0.48; DF = 2; K-W test). In contrast, endonasal volume (VOL) was significantly lower after sildenafil + VSS (P = 0.01), but not after placebo + VSS (P = 0.18). None of the other parameters monitored showed any significant variations. Rhinoscopy showed a characteristic increase of the volume of the inferior turbinates, with subjective differences between placebo and sildenafil. These preliminary results suggest that sildenafil reduces nasal volume, and that sexual stimulation may decrease nasal airflow by itself.
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PMID:Nasal congestion after visual sexual stimulation with and without sildenafil (Viagra): a randomized placebo-controlled study. 1790 71

Sildenafil (Viagra), a cyclic guanosine monophosphate-degrading phosphodiesterase 5 inhibitor, induces headache and migraine. Such headache induction may be caused by an increased neuronal excitability, as no concurrent effect on cerebral arteries is found. In 13 healthy females (23+/-3 years, 70.3+/-6.6 kg), the effect of sildenafil on a visual (reversing checkerboard) and a hypercapnic (6% CO2 inhalation) response was evaluated using functional magnetic resonance imaging (fMRI, 3 T MR scanner). On separate occasions, visual-evoked potential (VEP) measurements (latency (P100) and maximal amplitude) were performed. The measurements were applied at baseline and at both 1 and 2 h after ingestion of 100 mg of sildenafil. Blood pressure, heart rate and side effects, including headache, were obtained. Headache was induced in all but one subject on both study days. Sildenafil did not affect VEP amplitude or latency (P100). The fMRI response to visual stimulation or hypercapnia was unchanged by sildenafil. In conclusion, sildenafil induces mild headache without potentiating a neuronal or local cerebrovascular visual response or a global cerebrovascular hypercapnic response. The implication is that sildenafil-induced headache does not include a general lowering of threshold for a neuronal or cerebrovascular response, and that sildenafil does not modulate the hypercapnic response in healthy subjects.
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PMID:Cerebral haemodynamic response or excitability is not affected by sildenafil. 1920 79

The drug sildenafil (Viagra, Pfizer) and, more recently, tadalafil (Cialis, Lilly-Icos) and vardenafil (Levitra, Bayer), has drawn public attention to aphrodisiacs. The search for such substances dates back millennia. Adverse effects associated with these drugs include hypotension, tachycardia, headache, flushing, blurred vision, dyspepsia, and musculoskeletal pain. Although sildenafil has been marketed for erection of the penis, recent attention has been paid to its application for women, including enhancement of success of in vitro fertilization but also better sexual responses (increased desire, satisfaction, and orgasm) in cases of sexual disorders. Today, there is a debate on internet forums about the potential properties of sildenafil to enhance women's sexual pleasure. This laboratory was asked to analyze a 12-cm length of light brown hair submitted by a British police force following an allegation that a young female had been subjected to sexual assaults over a two-year period. The female was 15-17 years of age at the time. The alleged perpetrator was her stepfather, and there was some suspicion that drugs may have been administered to facilitate the attacks. After decontamination and segmentation (6 x 2-cm section), the specimen was analyzed by liquid chromatography coupled with tandem mass spectrometry after alkaline (pH 9.5) extraction using dichloromethane/ isopropanol/n-heptane (25:10:65, v/v/v). The limit of quantitation was 5 pg/mg. The proximal segment tested positive for sildenafil at 38 pg/mg, and all others proved negative. This was in accord with the victim's claim. In the absence of any controlled studies, it was impossible to put any quantitative interpretation on the measured concentration.
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PMID:Hair analysis to demonstrate administration of sildenafil to a woman in a case of drug-facilitated sexual assault. 1987 68

Sildenafil citrate (Viagra(R); Pfeizer US Pharmaceutical Group, New York, NY, USA) is a potent vasodilating agent to treat male erectile dysfunction. Among its adverse effects, hemorrhagic stroke has not been widely reported yet. We present a case of a 33-year-old healthy man who ingested 50 mg sildenafil a half hour before onset of headache, nervousness and speech disturbance. Head computed tomogram of this stuporous man showed huge intracerebral hemorrhage and thick subarachnoid hemorrhage, but angiography failed to disclose any vascular anomalies. Subsequent surgical procedure was followed, and rehabilitation was provided thereafter. Sildenafil seems to act by redistributing arterial blood flow, and concurrent sympathetic hyperactivity, which lead to such hemorrhagic presentation. Extreme caution should be paid on even in a young adult male patient wven without known risk factors.
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PMID:Subarachnoid Hemorrhage and Intracerebral Hematoma due to Sildenafil Ingestion in a Young Adult. 2037 74


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