My son has severe constipation after taking Paxil. Please help.

Hi doctor,

I have a twelve year old son, weighing 100 lbs. He was admitted to the hospital 12 days back for major depressive disorder (MDD), lack of sleep and having suicidal thoughts. He was prescribed Paxil 20 mg. I am concerned because he is exhibiting periods of low, melancholy moods and periods of extreme out of control highs. He has loud outbursts and feels like he cannot control himself. He previously suffered from chronic constipation since he was very young, to the point of having blockages that would severely expand his intestines. He had been doing great with that for nearly eight months after seeing a doctor but, severe constipation has returned because of Paxil. I would discuss these concerns with his psychiatrist, but we are in the early stages of his aftercare and I am not getting an appointment any sooner than a month from now. I worry that Paxil is not right for him and is making things worse.