Figure 4: How one mutation can stop some drugs working
Some drugs stop working after only one mutation.
These include NNRTIs (nevirapine, efavirenz, rilpivirine and etravirine), integrase inhibitors (raltegravir) and some nukes (3TC and FTC).
Figure 5: Resistance increases slowly with some drugs
With some other drugs, the first one or two mutations make little difference.
If you continue taking the same drug, more mutations will develop that eventually stop the drugs working. These include most PIs and some nukes.