Thanks for asking your question on Just Answer.
You are correct that the dose is 5 mg/kg by mouth once, then repeat in 2 weeks.
Here's how you calculate the dose:
Body weight in pounds divided by 2.2 gives you the body weight in kg.
For example, a 15 pound cat is 6.81 kg.
Then, take the kg weight and multiply it by 5 -- in the example above, the 15 pound (6.81 kg) cat would get 34 mg of the pyrantel.
Since each ml contains 50 mg, take 34 and divide by 50......34/50 = .68 mls. The dose of the pyrantel for the 15 pound cat is .68 mls.
Here is a dosing chart to use:
8 pound cat .36 mls
9 pound cat .40 mls
10 pound cat .45 mls
11 pound cat .5 mls
12 pound cat .54 mls
13 pound cat .6 mls
14 pound cat .63 mls
16 pound cat .68 mls.
I hope this helps. Please let me know if you need further info. Remember, only a single dose and repeat in 2 weeks. Do not use in sick of severely debilatated animals.