autofilter next and previous record problem

Hi experts,

I have a problem after using autofilter.
After useing autofilter i use the following code for going to the next or
previous records

next:
Private Sub but_next_Click()
Do
Set filterrange = filterrange.Offset(1, 0)
Loop While filterrange.EntireRow.Hidden = True
Call textboxen_vullen 'code to fill a lot of textboxes
End Sub

previous
Private Sub but_next_Click()
Do
Set filterrange = filterrange.Offset(-1, 0)
Loop While filterrange.EntireRow.Hidden = True
Call textboxen_vullen 'code to fill a lot of textboxes
End Sub

The problem is that there is no limit.
If i click previous enough times, i get an error message.
I would like it to stop at the first record of the filtered set

Also if i click the "next"button i want it to stop at the last record of the
filtered list

Can you please help me with this ?
Thanks,
Pierre