Exhibit
10.48  LOAN MODIFICATION AGREEMENT  This
Loan Modification Agreement is entered into as of May 28, 2003, by and between
Pharsight Corporation (the Borrower) and Silicon Valley Bank (Bank).  1.             DESCRIPTION OF
EXISTING OBLIGATIONS:  Among other Obligations
which may be owing by Borrower to Bank, Borrower is indebted to Bank pursuant
to, among other documents, a Loan and Security Agreement, dated June 13, 2001,
as amended or modified from time to time, (the Domestic Loan Agreement). The
Domestic Loan Agreement provides for, among other things, a Committed Revolving
Line in the original principal amount of Two Million Five Hundred Thousand
Dollars ($2,500,000) and a Committed Term Loan in the original principal amount
of Three Million Five Hundred Thousand Dollars ($3,500,000).  Furthermore, Borrower is indebted to Bank
pursuant to, among other documents, an Export-Import Bank Loan and Security
Agreement, dated June 13, 2001, as may be amended from time to time (the EXIM
Loan Agreement).  The EXIM Loan
Agreement provided for, among other things, an EXIM Committed Line in the
original principal amount of One Million Five Hundred Thousand Dollars
($1,500,000).  The Domestic Loan
Agreement and the EXIM Loan Agreement are collectively defined as the Loan
Agreements.  Defined terms used but not
otherwise defined herein shall have the same meanings as set forth in the Loan
Agreement.  Hereinafter, all indebtedness owing by Borrower to Bank shall be
referred to as the Obligations.  2.             DESCRIPTION OF COLLATERAL.
Repayment of the Obligations is secured by the Collateral as described in the
Loan Agreement.  Additionally, repayment
of the EXIM Committed Line is guaranteed by the Export-Import Bank of the
United States EXIM Bank pursuant to a master Guarantee Agreement between EXIM
Bank and Bank.  Hereinafter,
the above-described security documents and guaranties, together with all other
documents securing repayment of the Obligations shall be referred to as the
Security Documents.  Hereinafter, the
Security Documents, together with all other documents evidencing or securing
the Obligations shall be referred to as the Existing Loan Documents.  3.DESCRIPTION OF CHANGE IN TERMS.  A.Modification(s)
to Domestic Loan Agreement.  1.Section 6.6 entitled
Primary Accounts: Minimum and Target Balances is hereby amended in part to
provide that Borrower agrees that it shall deposit or invest through Bank (in
the sweep account or one of IPS Mutual Funds) at least two-third (2/3) of its
cash and cash equivalents (as determined pursuant to GAAP and as reflected in
Borrowers monthly financial statements).  2.Sub letter (a) under
Section 6.2 entitled Financial Statements, Reports, Certificates is hereby
amended in its entirety to read as follows:  (a)  Borrower will deliver to
Bank:  (i) as soon as available, but no
later than 30 days after the last day of each month, a company prepared
consolidated balance sheet and income statement covering Borrowers
consolidated operations during the period certified by a Responsible Officer
and in a form acceptable to Bank; (ii) as soon as available, but no later than
90 days after the last day of Borrowers fiscal year, audited consolidated
financial statements prepared under GAAP, consistently applied, together with a
an unqualified opinion of the financial statements from an independent
certified public accounting firm reasonably acceptable to Bank; (iii) a prompt
report of any legal actions pending or threatened against Borrower or any
Subsidiary that could result in   
   damages or costs to Borrower or any Subsidiary of $100,000 or more; (iv)
board of directors approved budgets, sales projections or other financial
information Bank request, and, in any event, within 30 days after the end of
Borrowers fiscal year.   3.Sub letter (b)
under Section 6.2 entitled Financial Statements, Reports, Certificate is
hereby amended in part to also include deferred revenue schedules within 20
days after the last day of each month end.  4.Sub letter (e) under Section 6.2 entitled Financial
Statements, Reports, Certificate is hereby incorporated to read as follows:  (e) On or prior to April 30th of each year, Borrower will
deliver to Bank its board of directors approved operating plan.  5.Section 6.7 entitled
Financial Covenants is hereby amended in its entirety to read as follows:  Borrower will maintain on the last day of each month:  (a)Liquidity.  Maintain Liquidity of at least twice the
amount of the outstanding aggregate balance of the Term Loan Advances.  (b)Remaining Months
Liquidity.  Maintain at least six months
Remaining Months Liquidity.  Remaining
Months Liquidity is defined as Liquidity minus the outstanding Term Loan
Advances divided by Net Cash Loss.  Net
Cash Loss is defined as a trailing three months average change in cash from
operations.  (c)Maximum Cumulative
Losses.  Beginning with the month ending
June 30, 2003 through the month ending May 31, 2004, Borrowers cumulative
monthly losses shall not exceed the levels forecast in its operating plan as
provided and approved by Borrowers board of directors on April 24, 2003 and as
submitted to Bank on May 5, 2003 by more than 20%.  Bank may, in its discretion, reset this covenant annually no
later than May 31st of each year.  7.The
following defined terms under Section 13.1 entitled Definitions are hereby
amended to read as follows:  Committed
Revolving Line is an extension of up to $1,400,000.  Revolving Maturity
Date is May 27, 2004.  B.            Modification(s) to EXIM Loan
Agreement.  1.The following
defined terms under Section 13 entitled Definitions are hereby amended to
read as follows:  Exim
Committed Line is an Advance of up to $600,000.  Exim
Maturity Date is May 27, 2004.  2.Sub letters (a), (c)
and (r) under the defined term Exim Eligible Foreign Accounts under Section
13 entitled Definitions are hereby amended and replaced to read as follows:  (a)Accounts with terms
of sale greater than 90 days.    
   (c)  Credit balances over 60 days
past original invoice due date.  (r)Accounts with open
account terms with balance more than 25% concentration of total foreign
Accounts, unless pre-approved by Bank.  4.             CONSISTENT
CHANGES.  The Existing Loan
Documents are hereby amended wherever necessary to reflect the changes
described above.  5.             NO DEFENSES OF BORROWER.  Borrower (and each guarantor and pledgor
signing below) agrees that, as of the date hereof, it has no defenses against
paying any of the Obligations.  6.             PAYMENT OF LOAN
FEE.  Borrower shall pay Bank a fee
in the amount of Seven Thousand Dollars ($7,000) (Domestic Loan Fee) and Nine
Thousand Dollars ($9,000) (EXIM Loan Fee) plus all out-of-pocket expenses.  7.             CONTINUING
VALIDITY.  Borrower (and each
guarantor and pledgor signing below) understands and agrees that in modifying
the existing Indebtedness, Bank is relying upon Borrowers representations,
warranties, and agreements, as set forth in the Existing Loan Documents.  Except as expressly modified pursuant to
this Loan Modification Agreement, the terms of the Existing Loan Documents
remain unchanged and in full force and effect. 
Banks agreement to modifications to the existing Obligations pursuant
to this Loan Modification Agreement in no way shall obligate Bank to make any
future modifications to the Obligations. 
Nothing in this Loan Modification Agreement shall constitute a
satisfaction of the Obligations.  It is
the intention of Bank and Borrower to retain as liable parties all makers and
endorsers of Existing Loan Documents, unless the party is expressly released by
Bank in writing.  Unless expressly
released herein, no maker, endorser, or guarantor will be released by virtue of
this Loan Modification Agreement.  The
terms of this paragraph apply not only to this Loan Modification Agreement, but
also to all subsequent loan modification agreements.  8.             CONDITIONS.  The effectiveness of this Loan Modification
Agreement is conditioned upon payment of the Domestic Loan Fee and EXIM Loan
Fee.  This Loan
Modification Agreement is executed as of the date first written above.  BORROWER:
  
  
  BANK:PHARSIGHT CORPORATION
  
  
  SILICON VALLEY BANKBy:
  /s/  Charles Faas
  
  By:
  /s/  Ron KundichName:
  Charles
  Faas
  
  Name:
  Ron
  KundichTitle:
  Chief
  Financial Officer
  
  Title:
  Vice
  President