So if you have a drug that causes Pulmonary Arterial Hypertension say by stimulating the serotonin 5HT2B receptor or inhibiting COX, the first symtoms you would expect to see would be tiredness and shortness of breath.

You might even expect to see more of this in the presence of other drugs that stimulate production of the toxic metabolite that stimulates this receptor. So if you’re a drug company you would want to avoid doing clinical studies with this drug and use piddily doses in your drug interaction studies, and you would misdirect people as to the metabolism and the actual changes in metabolism with the drug interaction studies.

You then might get edema, heart failure, and angina. Heart attacks, cardiac arrhythmias, and sudden death may take even longer in the majority of people, for example the more severe symptoms might take over a year like with Vioxx. But remember Vioxx is mainly taken by the elderly where you already have underlying cardiovascular disease and so it may show up earlier than in younge adults or children.

But of course there will always be some people who due to genetics or some other factor may have lethal complications almost immediately.

Some other things you may see are newborns dying in the first few days of life due to suffocation secondary to PAH, plus you may seen a lot of lost fetuses around 22 weeks when the placenta needs to vascularize more and even children with PAH and their placentas may be small at birth.

Since this is due to a basic mechanism you wouldn’t only see this with a single drug but possibly with other related drugs.

Salmon