1st dose orthostatic hypotension

[MudPhud20XX]

FA explains that alpha 1 selective blockers such as prazosin gives 1st dose orthostatic hypotension which differs from nonselective alpha blockers which give just orthostatic hypotension.

Can anyone explain "1st dose" here?

Many thanks in advance.

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[cbrons]

Means they get it the first time they take it

 

[MudPhud20XX]

ok so why wouldn't you get that in non-selective alpha blockers?

 

[Phloston]

ok so why wouldn't you get that in non-selective alpha blockers?

Don't overthink things. Any alpha-1 blockade can give you first-dose orthostatic hypotension. Just think about the mechanism. Doesn't matter if alpha-2 is also blocked (and alpha-2 effects are slower btw).

 

[Silverish]

Don't be surprised when questions go one step further with this concept and say that there is a problem with something like dopamine hydroxylase or an enzyme upstream of catecholamine synthesis and ask you what symptoms are likely to arise - orthostatic hypotension.