so i have a character that has poison immunity and was wondering if drugs would effect him or do they count as a poison and are than nullified?

I don't believe there are any items in there printed source materials that would qualify as "drugs". So that makes it hard to give a clear RAW answer. Really this would be entirely up to DM fiat.

Also keep in mind that there is immunity to Poison damage and there is immunity to the Poisoned condition.

The few examples of drugs in 5e (from wildmount I think eberron) are all mechanically poisons that inflict the poisoned condition.

Is your character immune to the poisoned condition or just poison damage? As they are separate things.

he is immune to both 

Quote from zan_shade >>

he is immune to both 

 Then they are probably nullified. I say probably, because it is really up to DM if the drug uses or requires the poisoned condition.

Poor you.  Get used to being sober.

Oh how much you will miss the most beloved of poisons, the grand, the glorious, the magnificent, Ethanol.

Up to the DM- can’t find it but think there’s more than one place in 5e that states that too much alcohol provides the poisoned condition…but that’s just alcohol so other drugs are purely up to the DM

It'd be up to DMs. For me a yes i consider intoxication with drug and alcool poison effects

The effects of intoxication aren't poison damage nor are they the poisoned condition so I can't see what would provide protection from them.

Quote from Ravnodaus >>

The effects of intoxication aren't poison damage nor are they the poisoned condition so I can't see what would provide protection from them.

• 10th level Paladins are immune to poisons, rather than poison damage or the poisoned condition.
• 10th level Monks are immune to poisons, rather than poison damage or the poisoned condition.

Both abilities linked above will protect you from a poison that doesn't inflict poison damage and doesn't inflict the poisoned condition.

So Im guessing the character in general is a dwarf?

Quote from quindraco >>

Quote from Ravnodaus >>

The effects of intoxication aren't poison damage nor are they the poisoned condition so I can't see what would provide protection from them.

• 10th level Paladins are immune to poisons, rather than poison damage or the poisoned condition.
• 10th level Monks are immune to poisons, rather than poison damage or the poisoned condition.

Both abilities linked above will protect you from a poison that doesn't inflict poison damage and doesn't inflict the poisoned condition.

OP already answered that his character is immune to the poisoned condition and poison damage.

If its of any interest to you, the Dev said in the past that being immune to poison included both poison damage and the poisoned condition. https://twitter.com/JeremyECrawford/status/509032893155258368?s=20&t=7dA2quPe8I2CjUROBOlDHw

@JeremyECrawford A monk with Purity of Body is immune to poison damage and the poisoned condition

And that the poisoned condition worked well for most intoxicant   https://twitter.com/JeremyECrawford/status/1131723902160236544?s=20&t=IbOL9Djx5YKc3w5tindyaQ

@JeremyECrawford There's no general rule for drunkenness in D&D. In our adventure design, we use the poisoned condition for someone who's really blasted. The poisoned condition works well for almost any toxin or intoxicant affecting a creature. 

so just to clarify the character has the Periapt of Proof against Poison which gives them immunity to poison and poisoned respectively 

thank you that was actually very interesting.