Maybe it is not necessary that approaching health policy and health development assistance from a human rights framework undermine effective use of resources - but it often does. Bill has given the example of the misallocation of AIDS program funds (excess spending on treatment relative to prevention). I'd add excess spending on AIDS relative to other illnesses and activities where you can get much bigger "bang for the buck" like treatment of diarrhea and pneumonia (big killers of children, significantly cheaper to treat, and prevent, then AIDS). I could give pages of examples of this in action. I have never been able to figure out why this predictable dynamic unfolds, but it does, again and again.
It seems to go something like this:
A human rights frame (similar to the universal frame) for promoting attention and spending on health - is often accompanied by effort to get governments to committ to these values. These committments get recorded in global venues and also in domestic foundational legislation. Sometimes in a country's constitution (as in a number of Latin American countries).
However much is available, resouces for health are still always scarce. In order to achieve good "value for money" in health governments must prioritize in some way: among services (using partly cost effectiveness) and among populations.
Human rights (and universal) framing undermines prioritization. It undermines it by giving health policy makers an easier "out" for not prioritizing. Also, even in countries where they have prioritized, groups that want more (of whatever) can use the human rights (or universal) frame (and government committments) to push the government to giving more to their issue. This often works - and undermines rational use of funds. It very often shifts spending to less cost effective uses, and because middle and upper income groups are more organized, vocal and efficatious, it often shifts spending towards the things they value. And away from services that are needed by the poor.
Colombia right now is experiencing exactly this phenomenon - as their ability to NOT spend on costly treatments (excluded from the insurance package) has been undermined by court cases by higher income people. The judges feel compelled by the constitutional committment to universal healthcare to rule in favor of expanding the package to cover the uncovered treatments. And, as a result, they can subsidize insurance for fewer and fewer poor people.
The human rights frame is nice when it is being used to get governments who are spending way too little on health to allocate more. However, the formal committments to health human rights do a lot of damage, and we should take it into account.