Could an ulcer also cause constipation

I was diagnosed with a duodenal ulcer in January after having an EGD.  For the past year or so, I've had a disruption with my normal B.M. pattern.  I've never had a long term problem with constipation, I used to have a B.M everyday but now, I might go every 4 days or so.  (I apologize for being so graphic) When I do have a B.M. I don;t have trouble straining or anything, the stool is very soft but much darker than usual.  I'm wondering...could the ulcer be the cause of the constipation?

[mammo]

The ulcer is probably bleeding causing the dark stool, and if I were you I'd contact your GI and address this new symptom with him.  I would think the ulcer would be healed enough by now to not be bleeding, so he needs to know about this.  Take care..

[CalGal]

Isis, are you taking any medication for the condition? If so, it's possible the medication may be causing the problems. Many GI medications, like others taken for a variety of conditions, can cause alterations in bowel habits.

[Isis905]

The only medication I've been taking for the ulcer is Prilosec.  I've been taking Exforge 10mg for high blood pressure for 4 years and have not had a problem with constipation.  The constipation and soft stools started before the Ulcer diagnoses and Prilosec.  I recently had a CT scan and was told I have spots on my liver.  I'm wondering if this could be a cause.