Xero said:
He asked you a stupid, condescending question (as parents are apt to do), and you responded in a snarky, sarcastic, disrespectful manner (as kids are apt to do).
I think that Xero has a point here, OP.
This looks like a classic action-reaction feedback loop. If this kind of interaction happens often between you and your dad, then it's a pattern, and it's a good thing to identify it so you can arrange it.
If you want to change a pattern, the only place you can act on is yourself. For instance, if you respond in a gentle, open tone, with a smile, something like:
"Hey dad, it's okay! I know you care and that's why you asked me this... I appreciate your care! But I am also a bright person, so I do read the instructions, okay? No worries!" and you give him a kiss....
...then next time he sees you take medication, he will remember this and feel at peace that you indeed are mature and wise enough so he needs not lecture you about it.
By changing your own attitude, you can "train" your dad into no longer treating you like a child. See what I mean?
It's called transactional analysis.
Your dad: "Did you read the instructions?!" (Controlling parent to immature child = condescending)
You: "Duh of course I did!" (Rebellious child to controlling parent = lack of respect). The rebellious response is a direct consequence of his own communication, but his next communication will be a direct response of your current one.
You need to replace this with an adult-adult conversation, in order to break the pattern and improve your relationship with your father on the long term.
Hope this helps!