Venlafaxine-induced ecchymoses and impaired platelet aggregation

A Hematoma in the Anterior Abdominal Muscle in a Woman Receiving Venlafaxine: A Literature Review of the Reports on Similar Cases

INTRODUCTION

Venlafaxine (VEN) is a selective norepinephrine reuptake inhibitor (SNRI) that mainly helps treat major depressive disorder and anxiety and panic disorders. It works by inhibiting the reuptake of serotonin (5-hydroxytryptamine, 5-HT) and noradrenaline (NA) by presynaptic neurons. Additionally, VEN administration has been linked with a bleeding predisposition that may be due to the inhibition of NA and 5-HT uptake by platelets which have their own receptors on their surface and are implicated in platelet aggregation.

CASE PRESENTATION

Herein, we report a case of a 54-year-old patient treated with VEN, who presented with a hematoma in the anterior abdominal muscle. We also present the observational studies and case reports highlighting the association of SNRIs use with various hemorrhagic complications ranging from gastrointestinal hemorrhage or vaginal bleeding to bleeding during or after surgery due to either thrombocytopenia or impaired platelet aggregation.

CONCLUSION

Given the cases of either reductions in the platelet count or impairment of platelet activity accompanied by bleeding events, every clinician should be aware of these possible adverse effects when prescribing SNRIs.

Impact of Venlafaxine on Platelet Count and Activity—Case Report and Narrative Review

Venlafaxine (VEN) is considered to be one of the most effective antidepressants. It belongs to the group of serotonin (5-HT) and noradrenaline (NA) reuptake inhibitors (SNRIs). NA and 5-HT have receptors on the surface of platelets and are involved in platelet aggregation. In this case study, we present the case of a patient treated for one of the types of myeloproliferative neoplasm (MPN), essential thrombocythemia (ET), in whom VEN was added to pharmacotherapy during the treatment of a severe episode of depression with psychotic symptoms. We observed a gradual reduction in platelet count when increasing the dose of VEN. We also present a narrative review of literature about the effect of VEN on platelet counts and activity. We conclude that, in the group of patients taking VEN, attention should be paid to the rare adverse effect of a decrease in the number of platelets.

Interactions between Antidepressants and Warfarin: A Review

Background:

Since warfarin has a very narrow therapeutic index, the interaction between warfarin and antidepressants is very critical and has potentially severe consequences. It is unclear whether clinicians have sufficient knowledge about the risk of bleeding when warfarin and antidepressants are used concomitantly.

Objective:

In this systematic review, we discuss the main considerations when using warfarin with antidepressants.

Methods:

The information about warfarin-antidepressant interactions was obtained from Google Scholar®, PubMed/MEDLINE® and a hand search of the published literature. The following research terms which were systematically combined with each other to find articles: warfarin, anticoagulant, interactions, antidepressant (and each antidepressant name individually), SSRI, SNRI, TCA, MAOI.

Results:

Several possible mechanisms that can cause bleeding when antidepressants and warfarin are used concomitantly, have been discussed. According to the available data, sertraline and citalopram/ escitalopram are safer antidepressants to use with warfarin, whereas fluoxetine and fluvoxamine have a higher interaction potential with warfarin. The remaining antidepressants appear to lie somewhere in between and have little empirical data to guide the clinicians.

Conclusion:

It is recommended that when an antidepressant is prescribed to a patient using warfarin, patient’s international normalized ratio (INR) level should be checked regularly. In this review, the interaction between warfarin and antidepressants, including new ones, were evaluated inclusively and in detail.

Acquired platelet defect associated with gabapentin treatment: a case-report

Gabapentin, a structural analog of gamma-aminobutyric acid, is used to treat peripheral neuropathic pain. Here we report the first case of platelet function disorder associated with gabapentin treatment in a 44-year-old woman without a history of bleeding. She presented with mucocutaneous bleeding approximately 1 month after initiation of gabapentin and platelet function tests showed no aggregation to arachidonic acid and epinephrine, a defective response to ADP and a slightly decreased response to collagen. Gabapentin's imputability was supported by the fact that all platelet functions were normalized 6 days after drug discontinuation, with the simultaneous disappearance of bleedings.

A review of drugs that contribute to bleeding risk in general dental practice

The risk of postoperative bleeding is a daily concern for many general dental practitioners. A thorough medical and medication history must be taken to consider all risk factors, particularly drugs, that contribute to bleeding risk. While the risk from drugs such as aspirin, warfarin and clopidogrel are well known, the extent to which new antiplatelet agents and direct oral anticoagulants affect bleeding risk is less well understood. In addition, there are drugs other than antithrombotics, such as antidepressants and complementary medicines that also impair haemostasis. The aim of this paper is to provide dentists with an updated overview of the drugs commonly encountered in general dental practice that can contribute to a patient's postoperative bleeding risk.

Hemarthrosis in a patient on warfarin receiving ceftaroline: a case report and brief review of cephalosporin interactions with warfarin

OBJECTIVE

To report a possible interaction between warfarin and ceftaroline, resulting in hemarthrosis, and provide readers with an understanding of mechanisms of interaction between cephalosporins and warfarin.

CASE SUMMARY

Ceftaroline was prescribed for an 85-year-old female with a therapeutic international normalized ratio (INR) hospitalized for the treatment of cellulitis. She was subsequently readmitted with shoulder pain and a supratherapeutic INR. The patient was diagnosed with hemarthrosis, presumably related to elevated INR. Evaluation using the drug interaction probability scale for warfarin and ceftaroline yielded a score consistent with a possible or probable interaction.

DISCUSSION

Cephalosporins may interact with warfarin through a variety of mechanisms, including potentiation of hypoprothrombinemia related to certain side chain groups, inhibition of P-glycoprotein, or alteration of gastrointestinal flora. All mechanisms reported in the medical literature as of April 2012 are briefly examined, but the latter is the most reasonable mechanism for a ceftaroline interaction with warfarin.

CONCLUSIONS

Health care providers should consider closely monitoring patients receiving antibiotics with activity against Enterobacteriaceae and warfarin, even if no direct mechanism of interaction has been reported. Further research regarding a ceftaroline-warfarin interaction is warranted.

Bleeding incidence with concomitant use of antidepressants and warfarin

INTRODUCTION

Bleeding is the major complication associated with warfarin therapy. Some antidepressants are also associated with increased bleeding risk. Warfarin and antidepressants are used frequently in combination, but it is unclear whether concomitant use increases the risk of bleeding beyond that with warfarin alone. The primary goal of this study was to determine whether the use of warfarin and an antidepressant increases the risk for bleeding outcomes compared with the use of warfarin alone. The secondary goal was to characterize the risk of bleeding in warfarin-treated patients taking one specific class of antidepressant, selective serotonin reuptake inhibitors (SSRIs).

MATERIALS AND METHODS

This was a retrospective, single-center, study of warfarin-treated patients prescribed (n = 46) and not prescribed (n = 54) an antidepressant. Medical records over 6 months were reviewed for international normalized ratio values, medical history, bleeding type and incidence, and hospitalization due to bleeding. Patients were included in the antidepressant group if they were taking concomitant warfarin and antidepressant therapy consistently for a period of 6 months and in the control group if they were not taking an antidepressant with warfarin.

RESULTS

The use of any antidepressant with warfarin was not associated with the incidence of any bleeding or major bleeding during the 6-month period. However, the use of an SSRI with warfarin was associated with an increase in any bleeding event (odds ratio 2.6, 95% confidence interval, 1.01-6.4 P = 0.04). The use of an SSRI remained a significant predictor of bleeding after accounting for other factors associated with bleeding risk.

CONCLUSIONS

Based on these data, it is important to clarify the interaction between warfarin and SSRIs in regard to bleeding risk given the high frequency of their concomitant use.

Bleeding after percutaneous endoscopic gastrostomy is linked to serotonin reuptake inhibitors, not aspirin or clopidogrel

BACKGROUND

Percutaneous endoscopic gastrostomy (PEG) is an invasive procedure that can result in bleeding. Guidelines recommend discontinuing clopidogrel for 7 to 10 days, but not withholding aspirin, before PEG. Serotonin reuptake inhibitors (SRIs) have been associated with an increased risk of GI bleeding.

OBJECTIVE

To determine whether there is an association between periprocedural aspirin, clopidogrel, or SRI use and bleeding in patients who underwent PEG tube placement.

DESIGN

Retrospective cohort study.

SETTING

Large quaternary-care academic medical center.

PATIENTS

A total of 990 patients (525 men) with a median age of 69.8 years who underwent PEG from January 1999 to April 2009.

INTERVENTIONS

PEG tube placement.

MAIN OUTCOME MEASUREMENTS

GI bleeding.

RESULTS

Sixteen patients (1.6%) had evidence of bleeding during the first 48 hours after PEG, and 12 patients (1.2%) had evidence of bleeding between 48 hours and 14 days after PEG. Thirty-six patients (3.6%) received high-dose aspirin (>325 mg), 27 patients (2.7%) received clopidogrel (75 mg), and 99 patients (10%) received an SRI before PEG. Twenty-four patients (2.4%) received high-dose aspirin, 25 patients (2.5%) received clopidogrel, and 130 patients (13.1%) received an SRI after PEG. Multivariate analysis demonstrated no association between periprocedural use of aspirin (at any dose) or clopidogrel and post-PEG bleeding. However, SRIs administered 24 hours or less before PEG were associated with a significantly higher odds of post-PEG bleeding (adjusted odds ratio 4.1; 95% CI, 1.1-13.4; P = .04).

LIMITATIONS

Retrospective, single-center study with limited statistical power despite a relatively large cohort of patients.

CONCLUSIONS

Use of aspirin or clopidogrel before or after PEG was not associated with procedure-related bleeding. SRI use in the 24 hours before PEG was associated with an increased risk of bleeding.

Effect of the selective serotonin reuptake inhibitor paroxetine on platelet function is modified by a SLC6A4 serotonin transporter polymorphism

BACKGROUND

Selective serotonin reuptake inhibitors (SSRIs) have been associated with an increased bleeding tendency.

OBJECTIVES

To prospectively quantify the dose-response effects of paroxetine and the influence of the serotonin transporter gene (SLC6A4) promoter polymorphism (5-HTTLPR) on platelet function.

METHODS

Nineteen drug-free psychiatric outpatients (44.5 +/- 10.8 years) were tested before and after 6 weeks of paroxetine treatment (20 mg day(-1)). Based on clinical symptoms, paroxetine dosages were increased (40-50 mg day(-1)) for 6 more weeks in 11 patients. Parameters related to platelet function were assessed by bleeding time, platelet function analyzer (PFA), platelet serotonin, platelet factor 4 (PF4), beta-thromboglobulin (beta-TG), and aggregation tests.

RESULTS

Paroxetine 20 mg day(-1) increased mean bleeding time by 1.2 min (95% confidence interval (95% CI) -0.2-2.7) and reduced median platelet serotonin level (463 ng 10(-9) platelets; inter quartile range (IQR) 361-666), and platelet ss-TG concentration (3.1 IU 10(-6) platelets; IQR 0.3-6.0). Other platelet parameters did not change significantly. Serial platelet aggregation tests did not become abnormal. Paroxetine dose-escalation did not further influence platelet function. However, 5-HTTLPR polymorphisms modified these effects: in L(A)/L(A)-carriers, bleeding times did not change (-0.2 min; 95% CI -0.6 to 0.9), while bleeding times significantly increased in <2L(A)-allele carriers (2.3 min; 95% CI 0.5 to 4.07; P = 0.032). Platelet serotonin decreases were larger in patients without L(A)-alleles (868 ng 10(-9) platelets; IQR 585 to 1213) than in > or =1 L(A)-allele carriers (457 ng 10(-9) platelets; IQR 392 to 598; P = 0.035). PFA closure time and PF4 increased significantly in patients without L(A)-alleles.

CONCLUSIONS

Paroxetine 20 mg day(-1) does not increase overall bleeding time, but impairs platelet function by decreasing the levels of platelet serotonin and platelet ss-TG. These paroxetine effects appear to be mediated by 5-HTTLPR, with most pronounced effects in patients without L(A)-alleles.

[Dermatological side effects during therapy with serotonin noradrenaline reuptake inhibitors]

Bleeding complications during therapy with serotonin norepinephrine reuptake inhibitors are a well-known phenomenon. We report a patient who developed ecchymosis during administration of duloxetine. As a correlate we detected a transient platelet dysfunction. After converting to venlafaxine therapy, another antidepressant with a dual mechanism of action, the patient showed normal platelet function. We finally achieved remission of the episode.