Top Definition
When upon taking a small to moderate dose of NyQuil or other OTC sleep aids which contain antihistamine as an active ingredient the ingested pharmaceutical produces undesired side affects such as jitteriness and/or increased heart rate which counter the intended result of sleep.
There is no known cure, treatment is focused on achieving sleep. Common treatments include: large quantities of liquor/cheap beer, more of said pharm, marijuana, drugs...
Man I really wanted to sleep before my flight but i had a NyQuil backfire and I was up all night with a dry ass mouth...
Yo I fuckin hate when NyQuil backfires, fuckin stresses you out the whole next day
by lostmonster March 19, 2009

The Urban Dictionary Mug

Lotsa space for your liquids.

Buy the mug

The Urban Dictionary Mug

Lotsa space for your liquids.

Buy the mug

The Urban Dictionary Mug

Your favorite word on a white mug.

Create a mug

The Urban Dictionary Mug

One side has the word, one side has the definition. Microwave and dishwasher safe. Lotsa space for your liquids.

Buy the mug

The Urban Dictionary T-Shirt

Soft and offensive. Just like you.

Buy the t-shirt

The Urban Dictionary T-Shirt

Smooth, soft, slim fit American Apparel shirt. Custom printed. 100% fine jersey cotton, except for heather grey (90% cotton).

Buy the t-shirt