(1) I've taken antibiotics for 10 weeks.
"have taken" denotes a present state. You say this at the end of the 10 weeks, and it does not imply anything about whether you will continue taking.
(2) I've been taking antibiotics for 10 weeks.
"have been taking" denotes a present state in the middle of an ongoing event. For 10 weeks already you have taken antibiotics and you're still taking it.
(3) I'm taking antibiotics for 10 weeks.
"am taking" by itself can either denote a present ongoing event (you are in the middle of the 10 weeks of antibiotics) or denote an imminent future such as according to what you choose to do (you have just decided to take antibiotics for 10 weeks and you are asserting your decision). Surprisingly, both could be conveyed by "I will be taking antibiotics for 10 weeks".
(4) I take antibiotics for 10 weeks.
This is only valid in a narrative account. It could be what you did in the past, which you are now retelling, but instead of using the past tense you use the present tense throughout to bring the audience into imagining the events as if they are unfolding right now.
(5) I took antibiotics for 10 weeks.
"took" denotes a past event. That past event lasted 10 weeks. We don't know whether it was a long time ago or just recently.
(6) I had taken antibiotics for 10 weeks.
"had taken" denotes a state resulting from a past event. Again, we don't know how long ago it was, but the 10 weeks ended before some other past event that you are talking about before or after this sentence. For example, "I had taken antibiotics for 10 weeks and still did not get better, so I started to doubt the doctor.".
(7) I had been taking antibiotics for 10 weeks.
"had been taking" denotes a past state in the middle of an ongoing event, very similar to "have been taking" except in the past. At that point in time, you had already spent 10 weeks on antibiotics, and you still were taking it! For example, "I had been taking antibiotics for 10 weeks already, and the symptoms had cleared up, but the doctor told me to continue for another 2 weeks just to be sure.".