any suggestions for mild flea treatment for aged, sick kitty?

[hlthe2b]

11. Capstar is safe for HEALTHY pets only. Active ingredient: (Nitenpyram)

this is a cat with end-stage cancer and any of the possible side effects could be dangerous:
Lethargy.
Depression.
Vomiting.
Diarrhea.
Decreased appetite.
Hyperactivity.
Trembling.
Neurologic signs (such as seizures or incoordination)
From its own label: Serious side effects (such as seizures, incoordination, or death) are more likely in animals that weigh less than 2 pounds, are younger than 8 weeks of age, or are already in poor health.

The poster was looking for the safest option for what he believes is a very short term need.