Yes. Research shows that Truvada for PrEP works for HIV prevention for people who inject drugs.
In case you’re curious to know more about the research, the Bangkok Tenofovir Study compared Truvada with a placebo pill in more than 2,400 participants who reported injecting drugs during the previous year in Bangkok, Thailand. Truvada was associated with a nearly 49% overall reduction in risk of HIV infection in IDU participants. Protection increased to 74% among those who took the study drug via directly observed therapy during clinic visits. Because participants in the study may have been both injecting drugs and having sex without condoms, it is still unclear whether Truvada specifically prevents “parenteral” HIV acquisition—that is, acquisition through injection rather than sex.