Route of drug administration Intraperitoneal(i.p.):Provides large absorbing surface,primarily used on lab animals.However- first pass effect,riskes including adhesions,infection Topical:useful for local effects,poisons and toxins, But-least effective for systemic absorption Intrathecal:local anesthetics,antibiotics,bypasses BBB and blood CSF barrier.Risks include infection, headaches Pulmonary:Useful for gases,vaports,aerosols,very rapid absorption.But-not used for irritating substances,difficult to control dose First pass effect of an oral drug Oral drug• Intraperitoneal (i.p.): Provides large absorbing surface, primarily used on lab animals. However – first pass effect, riskes including adhesions, infection • Topical: useful for local effects, poisons and toxins, But – least effective for systemic absorption • Intrathecal: local anesthetics, antibiotics, bypasses BBB and blood CSF barrier. Risks include infection, headaches • Pulmonary: Useful for gases, vaports, aerosols, very rapid absorption. But – not used for irritating substances, difficult to control dose Route of drug administration First pass effect of an oral drug