diff --git a/ext/pdo_oci/oci_statement.c b/ext/pdo_oci/oci_statement.c
index eaf803b76d2..10bb601d505 100644
--- a/ext/pdo_oci/oci_statement.c
+++ b/ext/pdo_oci/oci_statement.c
@@ -263,7 +263,7 @@ static sb4 oci_bind_output_cb(dvoid *ctx, OCIBind *bindp, ub4 iter, ub4 index, d
 	}
 
 	convert_to_string(parameter);
-	zval_dtor(parameter);
+	zval_ptr_dtor_str(parameter);
 
 	Z_STR_P(parameter) = zend_string_alloc(param->max_value_len, 1);
 	P->used_for_output = 1;
@@ -381,7 +381,7 @@ static int oci_stmt_param_hook(pdo_stmt_t *stmt, struct pdo_bound_param_data *pa
 							/* OCI likes to stick non-terminated strings in things */
 							*Z_STRVAL_P(parameter) = '\0';
 						}
-						zval_dtor(parameter);
+						zval_ptr_dtor_str(parameter);
 						ZVAL_UNDEF(parameter);
 					} else if (Z_TYPE_P(parameter) == IS_STRING) {
 						Z_STR_P(parameter) = zend_string_init(Z_STRVAL_P(parameter), P->actual_len, 1);