MSF has been offering this service, which includes treatment for HIV, tuberculosis (TB) and hepatitis, since 2012.
This year, 15 hepatitis C patients were started on direct-acting antivirals, which are easier to administer than previous recommended treatments and have shorter course durations and higher cure rates.
A leading Saudi cleric said a fatwa (religious ruling) issued against an earlier Pokemon card game also applied to the new mixed-reality app.
The 16-year-old edict said the game contained "forbidden images" and violated an Islamic ban on gambling.
Since its release this week, Gershad has been downloaded more than 16,000 times from the Google Play store, and more than 1,500 reports have been filed on it.
(It's only available on Android for now.) Gershad's creators say they see the app as a form of "nonviolent resistance" to Iran's morality police, who sometimes deploy heavy-handed tactics.
"Unfortunately in our country, awareness is poor among patients, as is social support and education about prevention," he told state media.
"Substance abuse and risky sexual behavior are related, but there is little or no discussion in schools about life skills or safe sexual relations," he said.
MSF continues to run its project in south Tehran, providing medical care, psychological support to excluded and marginalised groups.
Users who identify a checkpoint can anonymously mark it on the map to warn others, in much the same way that drivers flag traffic stops on the navigation app Waze.
When users report a sighting, a small police icon appears on the map for other users to see.