My son's gums hurt all the time. could this be a side effect of his new meds, welbrutrin xl? or a whitening tooth paste?

Yes, both: Wellbutrin (bupropion) has a side effect of dry mouth which can cause the gums to become red/inflamed and irritable to touch. The whitening toothpaste may have ingredients that your son is allergic to or can cause gum irritation. This on top of the dry mouth from his meds could make the situation worse.

Possibly yes: To correctly answer your question we need to know more. Are these symptoms a new development since he started to take this medication or this was always an issue? If it is worse since he started to take this med. Then this is related. Your son is having probably gingivitis (reversible inflamation of gums) and needs gentle but thorough brushing (2-3xday+floss) to remove plaque. Should help.

Not directly, but: One of the side effects of the medication he is taking is a dry mouth. It may lead to more active gum irritation due to reduction in salivary flow. Oral micro flora gets more aggressive and promotes gum inflammation, which in turn will create discomfort and pain, swelling and bleeding of the gum line. There may also be other reasons for gum pain. You will need to check with professionals.

Wellbutrin (bupropion) XL: Agree with earlier responses. Dry mouth is reported in 12 to 28% of people who take wellbutrin (bupropion). Gingivitis can be caused by this medication. This is a psychiatrist answering - so i will just address the issue of wellbutrin (bupropion).

Check with your : Pharmacy of the medicine side effect, but in some cases the teeth whitening past can cause sensitivity.