WebMD is correct; taking levodopa with MAOIs runs the risk of a hypertensive crisis and levodopa should not be taken for at least 2 weeks after MAOIs; the risk of taking RIMAs (specifically moclobemide) with levodopa is one of increased side effects which include anorexia, nausea, vomiting, agitation, postural hypotension, tachycardia, arrythmias, hypomania, psychosis, depression, headache, flushing, gastrointestinal bleeding, itching, rashes, abnormal involuntary movements.
AFAIK, l-tyrosine taken with MAOIs renders it more likely to be a vasopressor ie cause an elevation in BP.
The thing to recognise about such advice is that some people may not suffer such adverse effects, but there is a significant likelihood of having such a response that it can only be considered wise to avoid such combinations.
I am paranoid of my brain. It thinks all the time, even when I'm asleep. My thoughts assail me. Murderous lechers they are. Thought is the assassin of thought. Like a man stabbing himself with one hand while the other hand tries to stop the blade. Like an explosion that destroys the detonator. I am paranoid of my brain. It makes me unsettled and ill at ease. Makes me chase my tail, freezes my eyes and shuts me down. Watches me. Eats my head. It destroys me.