I am assuming from Louise's post that the daily Cialis is NOT producing a regular erection, Chris ... you are very lucky but probably in a minority.
Louise, if he hasn't tried yet, it is okay to take 3 tablets at once and see how that goes; if it doesn't produce an erection then he can try 4 tablets the next time (never take more than 4 at once). The GP is unlikely to notice if you request the repeat prescription a few days earlier sometimes! Do remember though that Cialis takes a few hours to work so if John took extra tablets at bedtime, the erection was most likely to happen the next morning.
The pellets (Muse) don't work for many men but may be a really good option for you, since the viridal was too successful.