You are correct, Losartan is usually prescribed at 25-50mg daily as a starting point, the MAX is 100mg. If your Doctor wanted you to have the maximum, perhaps 2x50mg would have been easier on you, by dividing it through the day. This medication can promote too much potassium in the body, which in turn can cause serious arrhythmia.
You are also right to question coming off your beta blocker abruptly, Metoprolol, because many people have to start taking them again and be weaned off. When I stopped my beta blockers it felt like my heart was bouncing all around the inside of my chest and I found it hard to breathe. Within 20 mins of taking the medication again, it all settled back down. It took me about 3 weeks to wean off my beta blockers. My beta blocker was a very strong one, and I was only on 1.25mg, so halving this was impossible. The pills were tiny and couldn't be cleanly broken. I had to increase the time between each pill instead. First I went to one every 48 hours and after a week, every 3 days. After managing one pill every 4 days I could finally stop and it felt great.
I don't know what a person is to do. I need a doctor to get along with to treat and prescribe for my COPD. I take Albuterol and Spiriva. I fear alienating yet another doctor over this BP medication and having no one to treat me for my COPD.
I did just find something that was interesting. The link, in the case you would want to read more, is http://www.theheart.org/article/1384629.do. I am taking the following out of the whole to publish here as I feel there might be some reassurance to others in this information as this doctor is supposed to be a renowned hypertension expert.
In an interview, Dr Norman Kaplan (University of Texas Southwestern Medical Center, Dallas) agreed. "One really has to be sure that we're giving reasonably comparable doses in order to make judgments about which of two or more drugs is more effective," he told heartwire. The renowned hypertension expert had commented on what he saw as limitations of the Swedish study in a published letter to the journal last year [2].
"I think that the lower dose of losartan simply isn't an adequate dose of the drug, and therefore it shouldn't be blamed for not giving comparable responses."
He points out that losartan is alone among ARBs in the US in being available as a generic and therefore is cheaper to use than candesartan (another ARB, valsartan [Diovan, Novartis], is set to go off patent later this year.) "That means a lot of physicians are using it to save on the cost of medications. So I think that it's a worthwhile point to make that the drug simply requires at least a 100-mg initial dose and consideration of twice-daily dosing rather than once a day."