ResearchSafe

Pentosan injection bruising, is this normal or am I injecting wrong

Posted by grinder265 in Safety & Side Effects - 2 points, 5 comments.

Been running pentosan for about 3 weeks now for some knee cartilage issues that kept flaring up during training. 2mg/kg weekly subcutaneous like the vet dosing extrapolation suggests. The stuff works pretty well honestly, my knee feels less crunchy on long runs.

Ngl though im getting some decent bruising at the injection site almost every time. Like yellowish patches that stick around for a few days. Not huge but noticeable. I rotate injection sites to my love handles and upper butt but still getting them.

Im a pharmacist so I know pentosan has mild anticoagulant properties but this seems a bit much for just that. Has anyone else experienced this? Wondering if I should be concerned about cumulative bleeding risk especially since I run ultramarathons and take ibuprofen occasionally after races. I know mixing NSAIDs with anticoagulant activity is generally not ideal but I figured the topical diclofenac I use on my ankle is pretty systemic-sparing.

Should I just push through it or get some bloodwork done to check coagulation times? Kind of a pain to explain to my doctor why I need it checked.

Comments

  • kyle_reads: So pentosan does have a heparin-like effect, mostly through potentiating antithrombin III. At the dose you are running that effect is real but usually mild, imo the bruising alone is probably just sub-q irritation plus a little bit of that anticoagulant action stacking up. Subcutaneous tissue can bleed pretty easily especially if you are hitting small vessels you cannot feel. The ibuprofen thing is where i would be more careful. Even occasional systemic NSAIDs plus pentosan can add up on platel
  • kai67: Yeah the sub-q bleeding point makes sense honestly, maybe I am just hitting small vessels and not noticing, I will slow down on the pin and make sure to actually aspirate properly. The NSAID comment is fair too, I have been popping ibuprofen after long runs without thinking about it, switching to topical sounds like an easy fix. Appreciate the breakdown 🔥
  • vik_b: Yeah that lines up with what i was thinking too. The anticoagulant angle is mild but it does add up week after week, especially if you are also taking something else that thins things out a bit. I switched to topical diclofenac for my knee flare ups and honestly it helps about the same as ibuprofen did for me, without the systemic worry. Worth trying if you have not already.
  • grinder265: Yeah the topical diclofenac swap is a good call honestly, ive been meaning to try that for the post race swelling instead of popping ibuprofen like candy. Did you notice any drop in effectiveness vs oral or is it basically the same for you? My main concern is after a 50 miler my knee gets properly puffy and oral NSAIDs at least touch that. Also how long have you been on pentosan, im curious if the bruising calmed down for you the longer you were on it or if it just kept happening at every site.
  • grinder265: Appreciate you taking it seriously bro. The ibuprofen switch to topical is honestly the easiest win, I started doing that last year and never looked back. One thing tho, when you say aspirate for sub-q pentosan, are you actually pulling back and seeing flash? Cuz sub-q bleeds are capillary mostly so you wont see a vein flash like IM.
  • grinder265: Yeah that tracks with what i was figuring. The injection site stuff i can probably chalk up to small vessels im not catching, ive been going a bit too fast and not letting the alcohol dry fully tbh so that might be making it worse. The NSAid point is a good one, i never really thought about it stacking up week over week since im only popping ibuprofen after races. Maybe once every couple weeks. Topical diclofenac is a smart swap honestly, ill grab some. You ever see the bruising get worse over

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