As I recall, the pharmacology included Zinc Sulfate, which the Hydroxychloroquine permitted into the cells, disrupting viral replication.
It was 200mg of hydroxychloroquine, taken twice daily for five days, with 500mg Azithromycin once daily for five days, and Zinc Sulfate, 200 mg once daily for five days, taken concurrently.
Leave out the zinc sulfate, and the virus does not get inhibited as well as it could (Azithromycin appears to have some inhibiting effect, but not on par with the zinc)