Exhibit 99.1

NeurogesX, Inc. Stephen Ghiglieri Executive Vice President, COO and CFO (650) 358-3310 The Ruth Group Stephanie Carrington (investors) (646) 536-7017 scarrington@theruthgroup.com   Jason Rando (media) (646) 536-7025 jrando@theruthgroup.com

NeurogesX to Host Investor Day on April 29

- Review of First Quarter 2011 Results -

- Update of Qutenza Launch -

San Mateo, Calif., (April 21, 2011) – NeurogesX, Inc. (NASDAQ: NGSX), a biopharmaceutical company focused on developing and commercializing novel pain management therapies, announced today that it will host an investor day on Friday, April 29, 2011, from 8:15 am - 11:00 am EDT at The New York Palace Hotel in New York. As part of the presentation, management will announce and review results for the first quarter ended March 31, 2011.

The Investor Day will be webcast live and archived for 30 days on the investor relations section of the NeurogesX website at www.neurogesx.com.

The Company will provide an update on the US launch of the Qutenza® (capsaicin) 8% patch and on the development of NGX-1998. A physician panel will discuss issues related to the practice of pain medicine, experiences and patient reactions to Qutenza.

About NeurogesX, Inc.

NeurogesX, Inc. (Nasdaq: NGSX) is a San Francisco Bay Area-based biopharmaceutical company focused on developing and commercializing novel pain management therapies. NeurogesX was founded on the concept that use of prescription-strength capsaicin could help manage the pain associated with neuropathic pain conditions. Since its inception, NeurogesX has leveraged its passion to help people with pain to efficiently develop this concept, resulting in the commercial launch of Qutenza® (capsaicin) 8% patch in 2010. The Company continues to apply its knowledge and expertise in the development of other novel treatments for pain.

The Company’s lead product, Qutenza, is a localized dermal delivery system containing prescription strength capsaicin that is currently approved in the United States and the European Union. Qutenza is now available in the United States for the management of neuropathic pain associated with postherpetic neuralgia (PHN). In Europe, Qutenza is

being marketed by Astellas Pharma Europe Ltd. (Astellas), the European subsidiary of Tokyo-based Astellas Pharma Inc., for the treatment of peripheral neuropathic pain in non-diabetic adults, either alone or in combination with other medicinal products for pain.

The Company is currently preparing to submit a supplemental new drug application (sNDA) to expand the U.S. label for Qutenza for the management of pain due to HIV-associated neuropathy (HIV-AN) also known as HIV-distal sensory polyneuropathy (HIV-DSP).

The Company’s most advanced product candidate, NGX-1998, is a topically applied liquid formulation containing a high concentration of capsaicin designed to treat pain associated with neuropathic pain conditions such as PHN. NGX-1998 has completed three Phase 1 studies and patient dosing is underway in a Phase 2 clinical trial in PHN patients.

The Company’s early-stage pipeline includes pre-clinical compounds which are prodrugs of acetaminophen and various opioids. The Company has evaluated certain of these compounds in vitro and in vivo.

Safe Harbor Statement

This press release contains forward-looking statements for purposes of the Private Securities Litigation Reform Act of 1995 (the Act). NeurogesX disclaims any intent or obligation to update these forward-looking statements, and claims the protection of the Safe Harbor for forward-looking statements contained in the Act. Examples of such statements include but are not limited to statements regarding the submission of a supplemental new drug application for label expansion of Qutenza. Such statements are based on management’s current expectations, but actual results may differ materially due to various risks and uncertainties, including, but not limited to: difficulties or delays in the commercialization of Qutenza, including with respect to the successful marketing or manufacture and supply of Qutenza; physician or patient reluctance to use Qutenza, despite the Company’s efforts and strategies to commercialize Qutenza; and difficulties or delays in the further development of Qutenza for additional indications. For further information regarding these and other risks related to NeurogesX’ business, investors should consult NeurogesX’ filings with the Securities and Exchange Commission.