By plotting kel versus CLCR it is possible to interpolate a value of kel for the patient
From this graph or by calculations the kelpatient = 0.0779 hr-1
Proceeding a described on http://18.104.22.168../Ch16/Ch1606.html and first described on http://22.214.171.124../Ch14/Ch1408.html.
R = Cpmin/Cpmax = 1/6 = e-kel*tau
Taking ln of both sides and solving for tau gives a value of 23.0 hr. Adjusting this upwards (to avoid extending the concentration range) give a new tau value of 24 hours.
The new R value is now e-0.0779 x 24 = 0.154
Maintenance dose can be calculated from Cpmax * V * (1 - R) = 6 x 0.28 x 79 x (1 - 0.154) = 112 mg (probably give 100 mg which would produce a Cpmax of 5.34 mg/L and Cpmin of 0.823 mg/L).
The required loading dose can be calculated as Cpmax * V = 6 x 0.28 x 79 = 133 mg (125 mg would produce a Cpmax of 5.65 mg/L).