I tend to use a palm-full each time. Perhaps I've been overdoing it as the extreme dryness does make my hair fall out.
I tried the Canadian version on holiday last Christmas and was quiet surprised. It's much softer than the UK one and it has a nice fragrance as well. Just like the Johnson's baby shampoo in the US. UK gets a raw deal, but Nizoral is still the best by far anywhere.
Boots does there own brand of anti dandruff shampoo which contains Ketoconazole same pink colour and smell virtually identical to nizoral and half the price.
I buy a generic form of ketoconazole shampoo (KETOISDIN) from isdin laboratories that has the same composition as Nizoral with the funny cost of 5.25€
And yes, ladies, it still has the famous pink colour you die for....
You don't need to use much. You could also prep the hair first with a regular shampoo then rinse before using the nizoral. This way you won't have to use the nizoral twice to get a good lather.
I use a generic form of nizoral too. Got the exact same ingredients but costs half the price. Its called 'Sebizole' its made in New Zealand so I don't think you can get it anywhere else, its so cheap $13 NZ. So thats about $9US.
The key ingredient is Kebocoznale or something like that :S Its on your pack of nizoral if you check.