Drano can be used to clear an AC drain line and in some cases it may work although just be aware that the Drano may cause harm to your AC drain line when used.
Drano should not be used in an AC drain as it could eat up the lines and do more damage.
Also Drano is not meant to clean AC lines of debris and it likely won't work to clear the AC drain line anyway.
However a good way to clean an AC drain line is to flush it with some vinegar and sometimes vinegar and baking soda.
You could pour some baking soda down the AC drain line and then pour some vinegar down the AC drain line and leave it sit for an hour or so.
Then use a garden hose to flush the AC drain line out.
Turn off your air conditioner.
Locate your condensate drain line.
Identify the access point on the drain line.
Flush with distilled vinegar.
Let the solution sit for 30 minutes.
Repeat each month.
You can start by pouring 1/4 cup of vinegar through a funnel into the drain; slowly add more if needed.
Let the vinegar sit for a few hours to eat away any algae build-up before flushing the pipe out with water.
By putting a quarter of a cup of distilled vinegar into your air conditioner's drain line, the vinegar kills mold, mildew, algae, fungus and bacteria.
It'll clear buildups and clogs. You should clean a drain line once a month.
Kill any harmful bacteria or buildup and make sure your system continues to operate at peak performance by cleaning your drain line every 30 days.
Signs that your AC drain line is clogged are.
Musty, moldy smell near your indoor unit or in air from the registers/vents.
Standing water near the indoor unit.
Water damage in areas near the indoor unit.
AC system is not cooling your home.
AC system shuts down or doesn't turn on.