To drink something is to swallow a liquid. The past tense of drink is drank. The past participle of drink is either drank or drunk, though the latter is used twice as often as the former.
A past participle is the adjective or adverb form of a verb. In this case, drunk is used exclusively with the verb have. Some will say that drank is not the past participle. However, it is listed in some dictionaries and used widely as such. If you are concerned about your audience, stick with have drunk and I drank.
It should be noted that to be drunk is to have consumed enough alcohol to lose one’s ability to make rational decisions.
I drink a lot of coffee, and I drink a well-brewed cup. [BBC]
When I say I drank a lot of Mountain Dew, I really mean it was the only thing I drank. [Huffington Post]
I must have drunk two liters of this chocolate-milk brain stuff. [The New York Times]
He said on the day had drunk ‘an inordinate amount of alcohol’ but added that it was ‘unlikely’ Lidice would ever appear in court again. [Derry Journal]
It’s a nice way of saying someone has drunk too much, and there is a list of things to look out for: falling over, falling asleep, crying or showing other signs of distress. [Financial Times]
Rottman is reported to have drank three bottles of vodka a day and been banned from several bars in Sotogrande over unpaid bills. [Express]
Except about half the audience, by a show of hands early on, had drank ayahuasca—an Amazonian brew that causes one to vomit and to have intense visions for hours, and which many say has incredible healing powers, leading to recovery from illnesses no other treatment touched, like depression, drug addiction and even psoriasis. [Newsweek]