Azithromycin can be given for 7 days?

Yes, but unusual: Seven days would be safe but is an unusual recommendation. Azithromycin usually is given in a single dose of 1,000 mg (for chlamydia and related STDs) or for 5 days (500 mg first day, 250 mg daily for 4 more days) (mainly for bronchitis, sinusitis, etc). Longer treatment, up to several weeks or even a few months, sometimes is used for certain other infections.

Azithromycin: Depends on the indication for treatment.