Trip Answers

Question answered:02/07/07 Warning! this question is over two years old.

We searched the TRIP and Medline databases but found no guidelines specifically discussing antiplatelet therapy in patients who have suffered a TIA or stroke and have a diagnosis of intersitital cystitis. However, we did locate guidance on antiplatelet therapy for the secondary prevention of stroke.

 

The PRODIGY guideline provides recommendations on choice of antiplatelet therapy. There is a section on the management of patients taking aspirin who are at increased risk of developing gastrointestinal adverse effects but it does not discuss gastritis.

 

 “…For people at high risk of GI adverse effects or who continue to have dyspepsia, the options are:

 

o Low-dose aspirin with a proton pump inhibitor for gastroprotection
o Clopidogrel instead of aspirin
o To avoid antiplatelet drugs (but this may not be advisable in a person at high cardiovascular risk)
• There is evidence that taking aspirin with a proton-pump inhibitor (PPI) may be a safer option than switching to clopidogrel.
• In addition, if a person develops dyspepsia while taking aspirin, there is evidence that switching to clopidogrel may not improve dyspeptic symptoms.”

 

The guideline adds:

 

“Dipyridamole used alone is generally not recommended for cardiovascular protection. Although there is some evidence that modified-release (MR) dipyridamole alone may be effective for the secondary prevention of stroke in people with transient ischaemic attack (TIA) or stroke, there is uncertainty regarding effectiveness in other groups. In particular, there are concerns that dipyridamole alone may not provide adequate protection against cardiac events…” [1]

 

A technology appraisal on clopidogrel and modified-released dipyridamole issued by NICE argues against the use of dipyridamole compared to aspirin alone:

 

“4.1.2.1 The European Stroke Prevention Study 2 (ESPS-2) was the only randomised controlled trial (RCT) identified that evaluated MR dipyridamole, aspirin, and MR dipyridamole combined with aspirin (aspirin/MR dipyridamole) compared with placebo. Patients included in the trial had experienced a TIA or an ischaemic stroke within the preceding 3 months. The study included 6602 patients randomised to aspirin (50 mg/day), aspirin/MR dipyridamole (50 mg/day plus 400 mg/day, respectively), MR dipyridamole (400 mg/day) or placebo…”

 

4.1.2.2 In the ESPS-2 study, aspirin (50 mg/day) alone was more effective than placebo, with an 18.1% reduction in the outcome of stroke compared with placebo. Compared with aspirin, MR dipyridamole treatment alone did not cause a reduction in the outcomes of stroke, death or any of the secondary outcomes. For the secondary outcome of MI, there was a small but statistically insignificant increase with MR dipyridamole compared with aspirin.” [2]

 

Leonardi-Bee reporting the findings of a meta-analysis of dipyridamole for preventing recurrent ischemic stroke states:

 

“BACKGROUND AND PURPOSE: Results from randomized controlled trials of dipyridamole, given with or without aspirin, for secondary prevention after ischemic stroke or transient ischemic attack (TIA) have given conflicting results. We performed a meta-analysis using individual patient data from relevant randomized controlled trials…”

 

“RESULTS: Recurrent stroke was reduced by dipyridamole as compared with control (OR, 0.82; 95% CI, 0.68 to 1.00), and by combined aspirin and dipyridamole versus aspirin alone (OR, 0.78; 95% CI, 0.65 to 0.93), dipyridamole alone (OR, 0.74; 95% CI, 0.60 to 0.90), or control (OR, 0.61; 95% CI, 0.51 to 0.71). The point estimates obtained for the comparisons of aspirin and dipyridamole versus control (OR, 0.63; significant) or versus aspirin (OR, 0.88; nonsignificant) were similar if the data from the largest trial, ESPS II (which provided 57% of data), were excluded. Similar findings were observed for nonfatal stroke. The combination of aspirin and dipyridamole also significantly reduced the composite outcome of nonfatal stroke, nonfatal myocardial infarction, and vascular death as compared with aspirin alone (OR, 0.84; 95% CI, 0.72 to 0.97), dipyridamole alone (OR, 0.76; 95% CI, 0.64 to 0.90), or control (OR, 0.66; 95% CI, 0.57 to 0.75). Vascular death was not altered in any group.”

 

They conclude:

 

“Dipyridamole, given alone or with aspirin, reduces stroke recurrence in patients with previous ischemic cerebrovascular disease. The combination of aspirin and dipyridamole also reduces the composite of nonfatal stroke, nonfatal myocardial infarction, and vascular death as compared with aspirin alone.” [3]

 

Given the lack of guidance on the secondary prevention of cerebrovascular events in patients with interstitial cystitis, the NLH Q & A Service can only recommend seeking advice from a local specialist in particular to establish whether dipyridamole would be contraindicated in intersititial cystitis.

References
1. CKS Library (PRODIGY). Antiplatelet treatment. Last revised October 2006. (http://www.cks.library.nhs.uk/antiplatelet_treatment/in_depth/management_issues).
2. NICE. Clopidogrel and dipyridamole for the prevention of artherosclerotic events. May 2005. (http://guidance.nice.org.uk/TA90/guidance/pdf/English).
3. Leonardi-Bee J, Bath PM, Bousser MG et al. Dipyridamole for preventing recurrent ischemic stroke and other vascular events: a meta-analysis of individual patient data from randomized controlled trials. Stroke. 2005 Jan;36(1):162-8. Epub 2004 Nov 29. (http://www.hubmed.org/display.cgi?uids=15569877).

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