diff --git a/psycopg/libpq_support.c b/psycopg/libpq_support.c
index 160c8491..6c0b5f8e 100644
--- a/psycopg/libpq_support.c
+++ b/psycopg/libpq_support.c
@@ -46,15 +46,15 @@
  * backend code. The protocol always uses integer timestamps, regardless of
  * server setting.
  */
-pg_int64
+int64_t
 feGetCurrentTimestamp(void)
 {
-    pg_int64 result;
+    int64_t result;
     struct timeval tp;
 
     gettimeofday(&tp, NULL);
 
-    result = (pg_int64) tp.tv_sec -
+    result = (int64_t) tp.tv_sec -
         ((POSTGRES_EPOCH_JDATE - UNIX_EPOCH_JDATE) * SECS_PER_DAY);
 
     result = (result * USECS_PER_SEC) + tp.tv_usec;
@@ -66,17 +66,17 @@ feGetCurrentTimestamp(void)
  * Converts an int64 to network byte order.
  */
 void
-fe_sendint64(pg_int64 i, char *buf)
+fe_sendint64(int64_t i, char *buf)
 {
-    uint32 n32;
+    uint32_t n32;
 
     /* High order half first, since we're doing MSB-first */
-    n32 = (uint32) (i >> 32);
+    n32 = (uint32_t) (i >> 32);
     n32 = htonl(n32);
     memcpy(&buf[0], &n32, 4);
 
     /* Now the low order half */
-    n32 = (uint32) i;
+    n32 = (uint32_t) i;
     n32 = htonl(n32);
     memcpy(&buf[4], &n32, 4);
 }
@@ -84,12 +84,12 @@ fe_sendint64(pg_int64 i, char *buf)
 /*
  * Converts an int64 from network byte order to native format.
  */
-pg_int64
+int64_t
 fe_recvint64(char *buf)
 {
-    pg_int64 result;
-    uint32 h32;
-    uint32 l32;
+    int64_t result;
+    uint32_t h32;
+    uint32_t l32;
 
     memcpy(&h32, buf, 4);
     memcpy(&l32, buf + 4, 4);
diff --git a/psycopg/libpq_support.h b/psycopg/libpq_support.h
index e57fae99..c8f10665 100644
--- a/psycopg/libpq_support.h
+++ b/psycopg/libpq_support.h
@@ -29,11 +29,10 @@
 
 /* type and constant definitions from internal postgres include */
 typedef unsigned PG_INT64_TYPE XLogRecPtr;
-typedef uint32_t uint32;
 
 /* have to use lowercase %x, as PyString_FromFormat can't do %X */
 #define XLOGFMTSTR "%x/%x"
-#define XLOGFMTARGS(x) ((uint32)((x) >> 32)), ((uint32)((x) & 0xFFFFFFFF))
+#define XLOGFMTARGS(x) ((uint32_t)((x) >> 32)), ((uint32_t)((x) & 0xFFFFFFFF))
 
 /* Julian-date equivalents of Day 0 in Unix and Postgres reckoning */
 #define UNIX_EPOCH_JDATE	2440588 /* == date2j(1970, 1, 1) */
@@ -42,8 +41,8 @@ typedef uint32_t uint32;
 #define SECS_PER_DAY	86400
 #define USECS_PER_SEC	1000000LL
 
-HIDDEN pg_int64 feGetCurrentTimestamp(void);
-HIDDEN void fe_sendint64(pg_int64 i, char *buf);
-HIDDEN pg_int64 fe_recvint64(char *buf);
+HIDDEN int64_t feGetCurrentTimestamp(void);
+HIDDEN void fe_sendint64(int64_t i, char *buf);
+HIDDEN int64_t fe_recvint64(char *buf);
 
 #endif /* !defined(PSYCOPG_LIBPQ_SUPPORT_H) */
diff --git a/psycopg/pqpath.c b/psycopg/pqpath.c
index 220ae246..d7283d0c 100644
--- a/psycopg/pqpath.c
+++ b/psycopg/pqpath.c
@@ -1555,7 +1555,7 @@ pq_read_replication_message(replicationCursorObject *repl, replicationMessageObj
     char *buffer = NULL;
     int len, data_size, consumed, hdr, reply;
     XLogRecPtr data_start, wal_end;
-    pg_int64 send_time;
+    int64_t send_time;
     PyObject *str = NULL, *result = NULL;
     int ret = -1;
 
diff --git a/psycopg/replication_message.h b/psycopg/replication_message.h
index 201b9fb4..b4d93d67 100644
--- a/psycopg/replication_message.h
+++ b/psycopg/replication_message.h
@@ -45,7 +45,7 @@ struct replicationMessageObject {
     int         data_size;
     XLogRecPtr  data_start;
     XLogRecPtr  wal_end;
-    pg_int64    send_time;
+    int64_t     send_time;
 };
 
 RAISES_NEG int psyco_replmsg_datetime_init(void);