Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Bleeding”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,477 records · Page 82Linked to original sources
PubMed1996

Assessment of a bleeding risk index in two cohorts of patients treated with oral anticoagulants.

In two cohorts of patients on oral anticoagulant therapy, routinely treated by the Leiden Thrombosis Service, the frequency of major bleeding complications was assessed during two years (1988 and 1991). With Poisson regression analysis the influence of the risk factors age, sex, target zone, achieved INR and type of coumarin derivative used were determined. Subsequently, a bleeding risk index was calculated, combining the results of the two cohorts. For various types of patients the relative risk of major bleeding complications was assessed. Age and achieved INR were the most important and consistent risk factors: rate ratio (RR) for age in 1988 1.46 per 10 years increase (95% confidence interval [CI] 1.20-1.78) and in 1991 1.57 per 10 years increase (95% CI 1.23-2.00); RR per unit increase in achieved INR in 1988 1.42 (95% CI 1.21-1.68) and in 1991 1.44 per unit increase in achieved INR (95% CI 1.18-1.74). Two methods were used to combine the results of 1988 and 1991. In the first method the mean bleeding risk index was calculated: In (incidence) [natural logarithm of the incidence rate of major bleeding] = -5.64+ 0.42 * age +0.26 * sex -0.29 * target range +0.36 * achieved INR -0.36 * coumarin type. In the second method only the consistent risk factors age and achieved INR were used: In (incidence) = -5.64 -0.42 * age +0.36 * achieved INR. These bleeding risk indexes can be used to assess the risk of major bleeding complications of individual patients and allow more individualized care by individual tailoring the desired anticoagulation.

Administration, Oral↗
PubMed1997

History of visible rectal bleeding in a primary care population. Initial assessment and 10-year follow-up.

OBJECTIVE: To determine whether a complaint of visible rectal bleeding that is elicited by a screening review of systems merits investigation and to assess the accuracy of a defined protocol to evaluate bleeding. DESIGN: Prospective cohort study. SETTING: Primary care clinics in a veterans medical center. PATIENTS: We used an 8-item review of systems to identify 297 individuals with visible rectal bleeding; 201 (68%) of these individuals completed a specified protocol consisting of double-contrast barium enema (DCBE) examination, rigid sigmoidoscopy, and follow-up visit after 6 to 12 months. Ten years later we verified the diagnosis in 131 (93%) of 141 patients whose initial evaluation suggested no cause, or a benign anorectal cause, of bleeding. MAIN OUTCOME MEASURES: Final diagnoses after 2 and 10 years; sensitivity and specificity of symptoms, DCBE, and rigid sigmoidoscopy. RESULTS: We diagnosed serious disease in 48 (24%) of the 201 patients; 26 had polyps, 9 had inflammatory bowel disease, and 13 (6.5%) had colon cancer. Symptoms did not predict the diagnosis. Neither DCBE nor rigid sigmoidoscopy alone was sufficiently sensitive to be used alone, but the combination of DCBE and rigid sigmoidoscopy had a sensitivity of 0.96 and a specificity of 0.76 for the diagnosis of polyps, cancer, or inflammatory bowel disease. CONCLUSIONS: Self-reported rectal bleeding detected by means of a review of systems was associated with a high likelihood of important pathology. Physicians should ask all adults about visible rectal bleeding and should visualize the entire colon in those who report bleeding.

Adult↗
PubMed1997

[Endoscopic and surgical treatment of acute bleeding gastroduodenal ulcers].

One of the basic problems of the treatment of acute bleeding from gastroduodenal ulcers concerns the correct timing of individual therapeutic steps. From 1992 to 1990 the I. Surgical Clinic in Brno performed the total of 438 urgent gastrofibroduodenoscopies, the most frequent finding being bleeding from the lesions in the area of the duodenal bulb. Endoscopic stoppage of bleeding was successful in 87.7% of patients. Failures in stopping the bleeding occurred in 18 cases and lead to urgent surgical intervention. On the basis of gained experience we recommend the following algorhithm in patients with acute bleeding from gastroduodenal ulcers: urgent endoscopy-endoscopic stoppage of bleeding. Relapse of bleeding requires endoscopic control with a new attempt of endoscopic therapy, in the case of failure it is urgent to intervene surgically. (Tab. 4, Ref. 14.)

Acute Disease↗
PubMed1997

Comparison of continuous and sequential transdermal progestogen with sequential oral progestogen in postmenopausal women using continuous transdermal estrogen: vasomotor symptoms, bleeding patterns, and serum lipids.

OBJECTIVE: The efficacy, bleeding patterns, and safety of continuous transdermal and sequential transdermal progestogen therapy were compared with those of oral progestogen therapy in postmenopausal women receiving transdermal estrogen. METHODS: In an open-label, 1-year (13 treatment periods, 28 days each), randomized study, 774 postmenopausal women were assigned to receive 50 micrograms/day of continuous trans dermal estradiol with either continuous or sequential transdermal norethisterone acetate (NETA) in daily doses of 170 or 350 micrograms in a single transdermal patch or sequential oral progestogen (1 mg norethisterone [NET] or 20 mg dydrogesterone/day). RESULTS: The average number of hot flushes/day decreased from prestudy by over 90% (P < .001), and this reduction was unaffected by different progestogen regimens. With sequential progestogen, bleeding incidence and the number of bleeding days did not change over the course of the study but were lower in the low-dose transdermal progestogen group. With continuous progestogen, the incidence of bleeding decreased in both the low- and high-dose groups, from 35% and 45% in treatment period 1 to 25% and 15%, respectively, at the end of treatment. Adverse event incidence was similar in all groups, with 23% to 36% of subjects reporting events possibly or probably related to HRT (excluding vaginal bleeding). Two cases of simple hyperplasia were reported (one in each low-dose progestogen group). Beneficial effects on coronary heart disease risk factors, such as reductions in total cholesterol and low-density lipoprotein cholesterol and increases in high-density lipoprotein-2 cholesterol levels, were measured in all treatment groups. Lipoprotein (a) was reduced in all but the oral progestogen group. CONCLUSIONS: Continuous and sequential transdermal estrogen/progestogen treatments with estradiol/NETA appear to be effective and safe alternatives to continuous transdermal estrogen and oral sequential progestogen for the treatment of menopausal symptoms. Continuous transdermal therapy with estradiol/NETA may be more acceptable for a majority of patients, i.e., those who wish to avoid monthly bleeds, whereas the sequential regimen may be preferable when the clinician and/or patient believes monthly bleeding to be appropriate.

Administration, Cutaneous↗
PubMed1997

Diagnostic value of endometrial curettage in abnormal uterine bleeding--a histopathological study.

Endometrial curettings from 458 patients presenting with abnormal uterine bleeding were studied. This included 220 (48%) patients with metrorrhagia, 187 (41%) with menorrhagia, 30 (6%) with postmenopausal bleeding, 13 (3%) with intermenstrual bleeding and 8 (1.74%) with polymenorrhagia. The histological findings were correlated with the pattern of abnormal bleeding in five different age groups. In 48.5% of the biopsies, histology assisted in diagnosing the cause of bleeding viz, intrauterine lesion in 25.5% and an ovulatory cycles in 22.9%. The endometrial lesions detected on histopathology included 2 (0.44%) endometrial adenocarcinomas, one (0.21%) carcinosarcoma, one (0.21%) metastatic mucinous adenocarcinoma, 41 (8.95%) benign polyps, 51 (11.1%) endometrial hyperplasia, 15 (3.28%) endometritis and 6 (1.3%) atrophic endometrium. The curettage was found to be of relatively low diagnostic value in menorrhagia and intermenstrual bleeding while its diagnostic yield was high in patients with postmenopausal bleeding and metrorrhagia.

Adult↗
PubMed1998

Management of lower gastrointestinal bleeding in colonic diverticular disease.

AIM: To evaluate the clinical course, diagnostic approach, therapeutic measures and results, in a series of 13 patients with colonic bleeding diverticula. MATERIAL AND METHODS: From 1973 to 1995, 72 patients were admitted with the diagnosis of lower gastroin testinal bleeding. Thirteen presented a colonic diverticula bleeding. Mean age was 65.2 years. Medical history, symptoms, diagnosis, treatment (conservative or surgical) and pathology were recorded. RESULTS: Main bleeding time was 3 days. Eight patients needed blood transfusion. All patients underwent colonoscopic examination and it was diagnostic in every patient. Four patients underwent surgery: one case, because of massive hemorrhage and the other three cases due to bleeding recurrence. Pancolectomy was performed in one patient, ileal resection in another and the other two were treated with a sigmoidectomy and a left hemicolectomy. Pathology analysis corroborated colonic diverticula diagnosis. There was no postoperative mortality. Bleeding recurrence did not occur either in postoperative period or in the follow-up. CONCLUSIONS: Colonic diverticular bleeding usually stops spontaneously, obtaining high rates of preoperative diagnosis with colonoscopy. Less than a third of the cases requires surgical resection.

Adult↗
PubMedDate not supplied

Comparison of office hysteroscopy, transvaginal ultrasonography and endometrial biopsy in evaluation of abnormal uterine bleeding.

OBJECTIVE: A comparison between office hysteroscopy, transvaginal ultrasonography and endometrial biopsy was performed, in terms of detection of intrauterine lesions. A secondary objective was assessment of evaluatory approach in the management of abnormal uterine bleeding in an outpatient setting. DESIGN: Prospective observational study. MATERIAL AND METHODS: A total of 54 women were evaluated for abnormal uterine bleeding. Assessment included performance of an endometrial biopsy, a transvaginal ultrasound scan followed by office hysteroscopy. Results of hysteroscopy were taken as the gold standard. Sensitivity and specificity of the investigations were assessed. The bleeding pattern was classified as heavy regular, irregular, postmenopausal and heavy or unscheduled bleeding on hormone replacement therapy. RESULTS: The incidence of focal intrauterine lesions in patients presenting with abnormal bleeding was 52% for all ages and 31% for the postmenopausal group. Seventy-five percent of the patients with Hb < 11 gm% and 67% with an enlarged uterus harbored a focal pathology. The incidence of lesions in patients with heavy regular bleeding was 74%. The sensitivity and specificity of transvaginal ultrasound when compared with results of hysteroscopy was 0.60 and 0.88 respectively. A normal endometrial biopsy had a negative predictive value of 51%. The sensitivity and specificity of endometrial biopsy were 0.04 and 0.83, respectively. CONCLUSION: Both transvaginal ultrasound and endometrial biopsy exhibited poor sensitivity for detection of focal intrauterine lesions. Considering the significantly high incidence of intrauterine lesions in patients presenting with abnormal bleeding, the most cost-effective approach appears to be proceeding with hysteroscopy early in assessment.

Adult↗
PubMed1990

Evaluation of an automated bleeding time device in the newborn.

Sick infants frequently developed impaired hemostasis as a secondary event. Abnormal platelet-vessel wall interaction contributes to the hemorrhagic side effects. Currently, the bleeding time is the best measure of in vivo platelet participation in small vessel hemostasis. Bleeding times in the newborn have been previously determined with an automated device designed for the adult or with nonautomated devices. The automated bleeding time device for the adult is not suitable for the infant (length 5 mm, depth 1 mm). We evaluated the performance of an automated bleeding time device designed specifically for the newborn making a cut 2.5 mm in length and 0.5 mm in depth. The results with the automated device showed a strong correlation with the modified template bleeding time device previously used for the newborn. The normal range was shorter and the sensitivity to abnormal vessel wall interaction was greater with the automated device. As well, the ease of determining the bleeding time with the automated device was considerably improved over the template device.

Bleeding Time↗
PubMed2004

Prolonged bleeding time and lupus anticoagulant: a second paradox in the antiphospholipid syndrome.

OBJECTIVE: Systemic lupus erythematosus and antiphospholipid syndrome (APS) often appear concomitantly. Lupus nephritis and antiphospholipid antibody-related ischemic nephropathy cannot be distinguished clinically, although their etiology and treatment differ greatly. Examination of a renal biopsy sample is therefore essential in order to provide the correct treatment. We have observed that patients with lupus anticoagulant (LAC), a serologic marker for APS, often have a prolonged bleeding time, which is a contraindication for performing a percutaneous renal biopsy. We undertook this study to evaluate systematically the bleeding time in 27 consecutive patients. METHODS: The bleeding time was measured in 27 patients who were persistently positive for LAC and who were not exposed to aspirin or nonsteroidal antiinflammatory drugs. Platelet function and von Willebrand factor (vWF) parameters were subsequently assessed in patients with a prolonged bleeding time. RESULTS: Twenty-one of 27 patients (78%) had a prolonged bleeding time despite a normal platelet count in the majority of patients (81%). Platelet functioning and vWF parameters in these 21 patients were normal, except for those in 1 patient with a mild storage pool disease. CONCLUSION: With this study, we introduce yet another paradox in the phenomenon of APS. Although a prolonged bleeding time is generally accepted to be a sign of defective primary hemostasis, LAC is associated with thrombosis. Further studies are needed to elucidate the mechanism behind this disturbance of primary hemostasis.

Adult↗
PubMed1991

The bleeding time effects of a single dose of aspirin in subjects receiving omega-3 fatty acid dietary supplementation.

Dietary supplementation with omega-3 fatty acids reduces platelet aggregation in subjects who usually eat a diet low in these fatty acids. Aspirin also has an antiplatelet effect. The clinical effects of the concomitant administration of these agents were examined in this double-blind controlled crossover trial. Twelve healthy adults were randomized to supplement their diet for 21 days with 8 g of omega-3 fatty acids or identical-looking olive oil capsules. At the end of each treatment period, bleeding times were obtained before and after the administration of one 325-mg aspirin tablet. Overall, percent change in bleeding time after omega-3 fatty acid supplementation was significantly prolonged compared with olive oil supplementation before aspirin administration but not after. Bleeding times were influenced significantly by the order of randomization in the two treatment groups. Changes in post-aspirin bleeding time varied in subjects after they received olive oil. Post-aspirin bleeding times after omega-3 fatty acid supplementation were prolonged compared with baseline values but not significantly prolonged when compared with those after olive oil administration. The authors concluded that the concomitant administration of a single dose of aspirin does not prolong bleeding time in subjects who eat a diet enriched by omega-3 fatty acids versus a diet enriched by olive oil.

Aspirin↗
PubMed1989

ITP in pregnancy: use of the bleeding time as an indicator for treatment.

ITP is a relatively common disorder seen in pregnancy. Current recommendations for management of patient with ITP recommend maintaining the platelet count above 50 x 10(9)/L and the bleeding time less than 20 min. It has been well documented that the bleeding time in ITP is disproportionately shortened in many patients relative to the platelet count. We present a prospective study of 24 ITP patients in whom the bleeding time was used as an indicator for therapeutic intervention in pregnancy. Indications for therapy with prednisone and/or intravenous gammaglobulin were the following: significant clinical hemorrhage due to thrombocytopenia; bleeding time of greater than 20 min at the baseline platelet count; for normalization of hemostasis prior to delivery or surgical procedure. Caesarean section was performed only in cases in which there were obstetrical indications for this mode of delivery or when the fetal platelet count (obtained by fetal scalp vein sample) was less than 50 x 10(9)/L. Of 24 patients with ITP, eight had significant thrombocytopenia (platelet count less than 50 x 10(9)/L) throughout pregnancy. Only two patients required prolonged prednisone therapy. Both suffered side effects of chronic prednisone administration. Four patients were treated with prednisone for a short course (10-14 days) at term to improve hemostasis for delivery. One patient was treated with intravenous gammaglobulin at term in an effort to prevent severe neonatal thrombocytopenia. Seven patients required caesarean section; the remaining 17 patients underwent vaginal delivery. Only one minor bleeding complication was seen - a small wound hematoma post caesarean section. In summary, using the bleeding time as an indicator for therapeutic intervention, treatment of ITP in pregnancy can be minimized. Thus, therapy related toxicity can be avoided.

Autoimmune Diseases↗
PubMed1992

Bleeding time and antiplatelet agents in normal volunteers.

Clinical trials have shown that antiplatelet agents are effective in the prevention of thrombosis in arterial diseases and increase bleeding time. To compare the effects of three such drugs [acetylsalicylic acid (ASA) at two dose levels, ticlopidine and indobufen] on bleeding time, we performed a randomized cross-over study on 12 normal subjects. All received the four treatments (ASA 300 mg daily and 500 mg twice daily, ticlopidine 250 mg twice daily and indobufen 200 mg twice daily, each for 6 days plus one dose on day 7) in a sequential manner with a washout period of 15 days between the treatments. Bleeding time was measured using a Surgicut device (Ortho, Milan, Italy) before treatment, 2 and 24 h after the first administration, and before and 2, 24, 48 and 72 h after the last administration. ASA (at both doses) and indobufen quickly induced a significant prolongation of bleeding time, but the effect of indobufen soon wore off after the treatment was stopped, unlike that of ASA. In contrast, ticlopidine treatment prolonged bleeding time only after the first 24 h, and after 7 days the mean value was significantly higher than with ASA (both doses) and indobufen. This significant difference in bleeding time between ticlopidine and the other drugs was still present 48 h after the end of treatment.

Adolescent↗
PubMed1993

Lack of usefulness of prolonged bleeding times in predicting hemorrhagic events in patients receiving the 7E3 glycoprotein IIb/IIIa platelet antibody. The TAMI Study Group.

Hemorrhagic events remain the most worrisome complication in patients receiving drugs that alter hemostasis for treatment of acute coronary syndromes. The 7E3 Fab monoclonal antibody provides a dose-dependent inhibition of platelet aggregation via the glycoprotein IIb/IIIa receptor. This study examines the correlation of hemostatic parameters with bleeding events in patients receiving intravenous 7E3 while enrolled in acute myocardial infarction and high-risk percutaneous transluminal coronary angioplasty pilot studies. Patients with acute myocardial infarction received 100 mg of tissue-type plasminogen activator over 3 hours followed by an escalating intravenous bolus dose of murine 7E3 (0.1 mg/kg [n = 5], 0.2 mg/kg [n = 22], 0.15 mg/kg [n = 13], 0.25 mg/kg [n = 20]). Patients in the high-risk angioplasty trial received a chimeric 7E3 bolus (up to 0.25 mg/kg) with (n = 32) or without (n = 15) intravenous continuous infusion of 7E3 (10 micrograms/min for 6 to 24 hours) after elective angioplasty. Patients in both studies received aspirin therapy (325 mg/day) and partial thromboplastin time-guided (1.5 to 2 times normal) heparin infusion. Bleeding events occurred in 34 of 124 patients (27%). The median template bleeding times (minutes) for patients in the groups with bleeding versus no bleeding events in the trials was 13.5 versus 14 and 30 versus 30, respectively (p = NS). In patients with myocardial infarction, a substantial decline in platelet count at 24 hours was associated with bleeding (p = 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1984

Prolonged bleeding time.

The bleeding time is the most frequently used test of platelet function. This review of the literature relating to the bleeding time outlines the causes and management of prolonged bleeding time. The bleeding time appears to have its greatest utility in evaluation of a patient with active bleeding or one with a well-documented bleeding history. It should not be used as a substitute for a clinical history, since there is insufficient information available to calculate its sensitivity, specificity, or predictive value with regard to peri- or postoperative hemorrhage.

Aspirin↗
PubMed1988

Vaginal bleeding patterns among women using one natural and eight hormonal methods of contraception.

Menstrual diary records were obtained from a total of 5257 women using nine different methods of contraception, one natural and eight hormonal. This paper presents a comparative analysis of their vaginal bleeding patterns. The analytic procedures follow the recommendations of a recent WHO workshop on bleeding pattern analysis, which involve dividing each subject's diary into successive 90-day reference periods, calculating ten indices for each period, and classifying women according to whether they have "clinically important" bleeding disturbances. In general, the findings of this analysis confirm those of previous studies. Women using the natural method, who were deliberately selected for the regularity of their menstrual cycles, averaged three bleeding/spotting episodes of length 5 days in each 90-day period, with very little variability within or between women. Subjects given a combined oral contraceptive had more regular patterns than any other treated group, with short (4-day) episodes and 23-24 day bleeding-free intervals. Progestogen-only pill users had more frequent, longer episodes and shorter, less predictable intervals than combined pill users. Contrary to widely-held beliefs, the progestogen-only pills produced fewer spotting days than the combined pills, and almost no spotting episodes at all. Nearly half of vaginal ring users experienced some menstrual disturbance in each period; their most common problems were irregular, infrequent or prolonged bleeding. Women using the long-acting injectable, depot medroxyprogesterone acetate, had totally unpredictable patterns, with infrequent but prolonged bleeding/spotting episodes. The incidence of amenorrhea rose from just under 10% in their first injection interval to over 40% in their fourth. The methods of analysis recommended by WHO in 1985 still require substantial refinement. Nevertheless, they are more sensitive than those used previously for WHO trials and produce an easily understood, clinically meaningful characterization of bleeding patterns.

Administration, Intravaginal↗
PubMed1988

Determinants of menstrual bleeding patterns among women using natural and hormonal methods of contraception. II. The influence of individual characteristics.

Menstrual diary records were obtained from women using either a natural method of contraception, a combined or progestogen-only oral contraceptive, a vaginal ring, or a long-acting injectable (DMPA). Within each method group, multiple regression analysis was used to examine the relationships between the subjects' bleeding patterns and their age, age at menarche, ponderal index, obstetric and contraceptive history and ethnic origin. The influence of ethnic origin was described in the preceding paper. Among combined pill users, increasing age was associated with more frequent spotting episodes. In both the untreated and combined pill groups, women with a higher ponderal index had less variable bleeding-free intervals; in the vaginal ring and DMPA groups, the more obese women had shorter bleeding/spotting episodes and longer bleeding-free intervals. Among combined oral contraceptive users, the most influential variable was the time since the end of the woman's last pregnancy: subjects who had been more recently pregnant had longer, less predictable episodes and shorter intervals. Previous oral contraceptive use was associated with more predictable bleeding patterns among women currently using either type of oral pill. In the vaginal ring and DMPA groups, subjects whose last pregnancy had ended in abortion had more bleeding/spotting days and episodes than those who had had a live birth. As reported previously, bleeding patterns were more closely related to the woman's geographical region of residence than to any other factor. The associations found with other individual characteristics were often inconsistent or difficult to interpret. A number of variables which could potentially influence menstrual bleeding patterns, such as nutritional status, were not measured and therefore could not be included in the analysis. However, contraceptive method and ethnic origin may be predominant influences, overriding any other factor.

Abortion, Induced↗
PubMed1994

Irregular bleeding, body mass index and coital frequency in Norplant contraceptive users.

Seventy-five women with a mean age of 27.5 years who requested Norplant implants for contraception were studied over a five-year period. The patients kept daily diaries of their vaginal bleeding and coital frequency, and were seen at least every six months at which time their weight was measured. This study examines the impact of Norplant implants use on menstrual regularity, body mass index and coital frequency. Irregular bleeding was most prevalent during the first two years of Norplant implants use and accounted for the primary reason for discontinuation of this method. No increase in Body Mass Index (BMI) was noted in Norplant implants users over the five-year study period. Women with irregular bleeding did not have a higher or lower BMI compared to women with regular bleeding and irregular bleeding patterns did not impact on coital frequency. Over five years, four pregnancies occurred during Norplant implant use. Norplant implants are a highly effective contraceptive method and women using this method should not expect an increase in body weight. Irregular bleeding is most frequent during the first two years of use and menstrual cyclicity resumes in the majority of women by the third year of use and continues to the fifth year of use.

Adult↗
PubMed1984

Prolongation of rat tail bleeding time by ketanserin: mechanisms of action.

Serotonin (5-HT) may play a regulatory role in platelet-vessel wall interaction. This can be reliably investigated by measuring bleeding time. Ketanserin is a recently developed selective 5-HT2 receptor antagonist, reportedly effective against both platelet and vascular 5-HT activation. Ketanserin (5-10 mg/kg) significantly prolonged tail bleeding time measured in conscious rats by two different techniques. While mianserin (a 5-HT2 receptor antagonist exhibiting alpha-adrenolytic activity) also prolonged bleeding time, methysergide, metergoline and cyproheptadine did not. All three compounds acted as 5-HT2 receptor antagonists with appreciable affinity for 5-HT1 receptors. On the other hand, bleeding time was prolonged by either prazosin (a selective alpha 1-adrenoceptor antagonist) or labetalol (an alpha 1- and beta-receptor antagonist). In contrast it was not affected by phentolamine or nicergoline (alpha 1-alpha 2-receptor antagonists) nor by propranolol (a beta-receptor antagonist). The effect of prazosin was significantly increased by combining it with either ketaserin or metergoline. Depletion of platelet serotonin by reserpine did not result in any modification of bleeding time, unless reserpine was combined with an inhibitor of 5-HT synthesis. Platelet activation by 5-HT was neither potentiated by norepinephrine nor prevented by prazosin or phentolamine whereas ketanserin and methysergide were equally effective inhibitors. These findings argue against a role of platelet and/or vascular 5-HT2 receptors in the antihemostatic effect of ketanserin in rats. This drug prolongs bleeding time by antagonising vascular adrenoceptors (prazosin-like effect) and/or by preventing a synergistic interaction between 5-HT and catecholamines at the vascular level.

Animals↗