Install perl Cache::Memcached from CPAN or your upstream distribution vendor.

- perl-Cache-Memcached on redhat/fedora
- libcache-memcached-perl on debian/ubuntu

Generate template for desired port. For memcached listening on different address adjust template and stats collecting script accordingly.

  export PORT=11211; sed -e "s/#PORT#/$PORT/g" memcached_t.xml > memcached_t_$PORT.xml

Add userparams into /etc/zabbix/zabbix_agentd.conf.

  UserParameter=memcached.stat[*],awk '/^STAT $1 / {print $$3}' /tmp/_zabbix_memcached_stat_$2
  UserParameter=memcached.mem[*],ps -e -orss,cmd | grep -vE '(awk|grep)' | awk '/memcached.*$1/ {print $$1}'

Add cron job for runtime statistics precollection into files (crontab -e).
 
  * * * * * /usr/local/bin/memcached_stats.pl