Dragons began brightly and were rewarded when Coghlan went over from close range 12 minutes in, with Will Reed converting for a 7-0 lead.
.Both sides scored three tries at the Hive Stadium but Giacomo Da Re’s seven points with the boot proved the difference and Edinburgh were chasing the game for the bulk of the United Rugby Championship encounter.
Scarlets secured a third successive win in the United Rugby Championship by beating Zebre Parma 30-8 in Llanelli.
Munster legend Donncha O'Callaghan has blasted his former team following their shock to defeat to minnows Zebre Parma in Round 2 of the URC.
Zebre Parma made history by securing their first-ever victory over Munster with a 42-33 bonus-point win in the United Rugby Championship.
Edinburgh had to fight all the way against a spirited Zebre side but in the end they secured a 40-14 bonus-point victory.
Academy graduate Matthew Devine impressed as Connacht blitzed Zebre 54-16 in the United Rugby Championship at Dexcom Stadium.
United Rugby Championship leaders Leinster continued their relentless play-off push by beating Zebre 31-7 in Parma.
.Munster moved back into play-off territory in the BKT United Rugby Championship after beating battling Zebre Parma 45-29 at Virgin Media Park on the back of five first-half tries.
Edinburgh were far from their best and made Zebre Parma pay for a lack of discipline as they left it late to secure a hard-fought 24-19 BKT United Rugby Championship victory at Stadio Sergio Lanfranchi.