passing parameters to multiple statements

I'm planning to use multiple statements via libpq. Before starting coding
I'm trying to understand are there any limitations on passing parameters.
E.g. would the following work:
PQexecParams(conn, "BEGIN;INSERT INTO tbl VALUES($1,$2);SELECT
lastval();SELECT * INTO AUDIT FROM (SELECT $3, 'tbl action',
lastval());COMMIT;", 3, ...);

Thank you!