Symptoms of the Arthropleura poisoning include uncontrolled shaking, anaphylaxis and short term memory loss in recovered patients.
Once bitten the venom then begins to slowly attack the central nervous system, not so far removed from modern biochemistry as to be totally ineffective, and any enzyme inhibitor would be detrimental to an extent. However, as the Arthropleura are detritus eaters they make no attempt to eat their victims. Fortunately the hospital staff discovered that the venom has a modern day equivalent, thus producing an anti-venom.
An Arthropleura also reappeared in the series finale of Series 2 as one of the many creatures captured by Leek. When the security system holding it failed, it ran amok, although how it had survived thus far without the carboniferous atmosphere that it needed to live, remains a mystery.