Make sure you have admin access to your server.
Locate your PEAR installation by using 'which' command.
$ which pear
/usr/local/php5/bin/pear
Then, to check list of all PEAR packages that has been installed in your Mac, run 'pear list' command
$ sudo pear list
Installed packages, channel pear.php.net:
=========================================
Package Version State
Archive_Tar 1.3.1 stable
Benchmark 1.2.4 stable
Console_Getopt 1.2 stable
DB 1.7.6 stable
DB_DataObject 1.8.2 stable
Date 1.4.6 stable
HTML_Common 1.2.2 stable
HTML_QuickForm 3.2.5 stable
HTML_Template_IT 1.1 stable
Mail 1.1.9 stable
Net_UserAgent_Detect 2.0.1 stable
PEAR 1.4.8 stable
Savant2 2.4.2 stable
XML_RPC 1.2.2 stable
phing 2.1.1 stable
If you wish to install new packages, do the following:
$ sudo pear install -o DB


