How safe to use Stronghold flea treatment after using Bob Martin?

I've read up a fair amount about it now and regret my actions. I bought some Bob Martin flea treatment from the supermarket to treat my two who , despite being indoor cats have become infested. It doesn't seem to have served it's purpose some five days later and so I've been to the vet and bought the Stronghold. It's five days since they were treated with the Bob Martin and my question is this: is it now safe to apply the Stronghold or should I wait?  Any thoughts on the matter or any similar experiences shared would be very helpful. Thanks

I suggest you call the vet's office and read them the ingredients of each of the flea medications.  The vet can tell you whether or not it is safe to apply the Stronghold after the Bob Martin.

Thank you I'll do that!