diff --git a/examples/testlibpq3.rs b/examples/testlibpq3.rs
index f6bdab8..fefdbec 100644
--- a/examples/testlibpq3.rs
+++ b/examples/testlibpq3.rs
@@ -61,7 +61,7 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
      */
 
     /* Here is our out-of-line parameter value */
-    let param_values = vec![Some(b"joe's place\0".to_vec())];
+    let param_values: Vec<Option<&[u8]>> = vec![Some(b"joe's place\0")];
 
     let res = conn.exec_params(
         "SELECT * FROM test1 WHERE t = $1",
@@ -91,7 +91,7 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
     let binary_int_val = htonl(2);
 
     /* Set up parameter arrays for PQexecParams */
-    let param_values = vec![Some(binary_int_val)];
+    let param_values = vec![Some(&binary_int_val[..])];
     let param_formats = vec![libpq::Format::Binary];
 
     let res = conn.exec_params(
@@ -165,6 +165,6 @@ fn ntohl(netlong: &[u8]) -> Result<i32, std::array::TryFromSliceError> {
     netlong[..4].try_into().map(i32::from_be_bytes)
 }
 
-fn htonl(hostlong: i32) -> Vec<u8> {
-    hostlong.to_be_bytes().to_vec()
+fn htonl(hostlong: i32) -> [u8; 4] {
+    hostlong.to_be_bytes()
 }
diff --git a/src/connection/_async.rs b/src/connection/_async.rs
index d1ec703..fd6ba77 100644
--- a/src/connection/_async.rs
+++ b/src/connection/_async.rs
@@ -32,7 +32,7 @@ impl Connection {
         &self,
         command: &str,
         param_types: &[crate::Oid],
-        param_values: &[Option<Vec<u8>>],
+        param_values: &[Option<&[u8]>],
         param_formats: &[crate::Format],
         result_format: crate::Format,
     ) -> crate::errors::Result {
@@ -118,7 +118,7 @@ impl Connection {
     pub fn send_query_prepared(
         &self,
         name: Option<&str>,
-        param_values: &[Option<Vec<u8>>],
+        param_values: &[Option<&[u8]>],
         param_formats: &[crate::Format],
         result_format: crate::Format,
     ) -> crate::errors::Result {
diff --git a/src/connection/_exec.rs b/src/connection/_exec.rs
index 2a5bc4e..d7c1441 100644
--- a/src/connection/_exec.rs
+++ b/src/connection/_exec.rs
@@ -24,7 +24,7 @@ impl Connection {
         &self,
         command: &str,
         param_types: &[crate::Oid],
-        param_values: &[Option<Vec<u8>>],
+        param_values: &[Option<&[u8]>],
         param_formats: &[crate::Format],
         result_format: crate::Format,
     ) -> crate::PQResult {
@@ -99,7 +99,7 @@ impl Connection {
     pub fn exec_prepared(
         &self,
         name: Option<&str>,
-        param_values: &[Option<Vec<u8>>],
+        param_values: &[Option<&[u8]>],
         param_formats: &[crate::Format],
         result_format: crate::Format,
     ) -> crate::PQResult {
diff --git a/src/connection/mod.rs b/src/connection/mod.rs
index 6a53a82..9e4f693 100644
--- a/src/connection/mod.rs
+++ b/src/connection/mod.rs
@@ -80,7 +80,7 @@ impl Connection {
     }
 
     fn transform_params(
-        param_values: &[Option<Vec<u8>>],
+        param_values: &[Option<&[u8]>],
         param_formats: &[crate::Format],
     ) -> (Vec<*const libc::c_char>, Vec<i32>, Vec<i32>) {
         if param_values.is_empty() {
@@ -114,7 +114,7 @@ impl Connection {
         prefix: &str,
         command: &str,
         param_types: &[crate::Oid],
-        param_values: &[Option<Vec<u8>>],
+        param_values: &[Option<&[u8]>],
         param_formats: &[crate::Format],
     ) {
         use std::fmt::Write;
@@ -284,7 +284,7 @@ mod test {
         let results = conn.exec_params(
             "SELECT $1",
             &[crate::types::INT4.oid],
-            &[Some(b"1\0".to_vec())],
+            &[Some(b"1\0")],
             &[],
             crate::Format::Text,
         );
@@ -299,7 +299,7 @@ mod test {
         let results = conn.exec_params(
             "SELECT $1",
             &[crate::types::INT4.oid],
-            &[Some(b"foo\0".to_vec())],
+            &[Some(b"foo\0")],
             &[],
             crate::Format::Text,
         );
@@ -310,13 +310,7 @@ mod test {
     #[should_panic]
     fn exec_text() {
         let conn = crate::test::new_conn();
-        let _ = conn.exec_params(
-            "SELECT $1",
-            &[],
-            &[Some(b"foo".to_vec())],
-            &[],
-            crate::Format::Text,
-        );
+        let _ = conn.exec_params("SELECT $1", &[], &[Some(b"foo")], &[], crate::Format::Text);
     }
 
     #[test]
@@ -328,12 +322,8 @@ mod test {
         let results = conn.describe_prepared(Some("test1"));
         assert_eq!(results.nfields(), 1);
 
-        let results = conn.exec_prepared(
-            Some("test1"),
-            &[Some(b"fooo\0".to_vec())],
-            &[],
-            crate::Format::Text,
-        );
+        let results =
+			conn.exec_prepared(Some("test1"), &[Some(b"fooo\0")], &[], crate::Format::Text);
         assert_eq!(results.value(0, 0), Some(&b"fooo"[..]));
     }
 
@@ -360,7 +350,7 @@ mod test {
         conn.send_query_params(
             "SELECT $1",
             &[crate::types::TEXT.oid],
-            &[Some(b"fooo\0".to_vec())],
+            &[Some(b"fooo\0")],
             &[],
             crate::Format::Text,
         )
@@ -397,7 +387,7 @@ mod test {
             .unwrap();
         while conn.result().is_some() {}
 
-        conn.send_query_prepared(None, &[Some(b"fooo\0".to_vec())], &[], crate::Format::Text)
+        conn.send_query_prepared(None, &[Some(b"fooo\0")], &[], crate::Format::Text)
             .unwrap();
         assert_eq!(conn.result().unwrap().value(0, 0), Some(&b"fooo"[..]));
         assert!(conn.result().is_none());