Forward-Looking Statements

This Quarterly Report on Form 10-Q contains forward-looking statements that involve substantial risks and uncertainties. These forward looking statements include, but are not limited to, statements about:

• our ability to maintain and increase market demand for, and sales of, Sumavel DosePro;

• our ability to successfully execute our sales and marketing strategy for the commercialization of Sumavel DosePro;

• the progress and timing of clinical trials for our product candidates;

• the timing of submissions to, and decisions made by, the FDA and other regulatory agencies, including foreign regulatory agencies, and demonstrating the safety and efficacy of Zohydro or any other product candidates to the satisfaction of the FDA and such other agencies;

• adverse side effects or inadequate therapeutic efficacy of Sumavel DosePro that could result in product recalls, market withdrawals or product liability claims;

• the safety and efficacy of Zohydro and our other product candidate;

• the market potential for migraine treatments, and our ability to compete within that market;

• the goals of our development activities and estimates of the potential markets for our product candidates, and our ability to compete within those markets;

• estimates of the capacity of manufacturing and other facilities to support our product and product candidates;

• our ability to ensure adequate and continued supply of Sumavel DosePro to successfully meet anticipated market demand;

• our expected third party research and development costs for Zohydro remaining through potential regulatory approval from the FDA;

• our and our licensors ability to obtain, maintain and successfully enforce adequate patent and other intellectual property protection of our products and product candidates and the ability to operate our business without infringing the intellectual property rights of others;

• our ability to obtain and maintain adequate levels of coverage and reimbursement from third-party payors for Sumavel DosePro or any of our other product candidates that may be approved for sale, the extent of such coverage and reimbursement and the willingness of third-party payors to pay for our products versus less expensive therapies;

• the impact of healthcare reform legislation; and

• projected cash needs and our expected future revenues, operations and expenditures.

The forward-looking statements are contained principally in the sections entitled "Risk Factors" and "Management's Discussion and Analysis of Financial Condition and Results of Operations." In some cases, you can identify forward-looking statements by the following words: "may," "will," "could," "would," "should," "expect," "intend," "plan," "anticipate," "believe," "estimate," "predict," "project," "potential," "continue," "ongoing" or the negative of these terms or other comparable terminology, although not all forward-looking statements contain these words. These statements relate to future events or our future financial performance or condition and involve known and unknown risks, uncertainties and other factors that could cause our actual results, levels of activity, performance or achievement to differ materially from those expressed or implied by these forward-looking statements. We discuss many of these risks, uncertainties and other factors in this Quarterly Report on Form 10-Q in greater detail under the heading "Item 1A - Risk Factors."

Given these risks, uncertainties and other factors, we urge you not to place undue reliance on these forward-looking statements, which speak only as of the date of this report. You should read this Quarterly Report on Form 10-Q completely and with the understanding that our actual future results may be materially different from what we expect. For all forward-looking statements, we claim the protection of the safe harbor for forward-looking statements contained in the Private Securities Litigation Reform Act of 1995. We undertake no obligation to revise or update publicly any forward-looking statements, whether as a result of new information, future events or otherwise, unless required by law.

DosePro ®, Intraject®, Relday™, Sumavel®, Zogenix™ and Zohydro™ are our trademarks. All other trademarks, trade names and service marks appearing in this Quarterly Report on Form 10-Q are the property of their respective owners. Use or display by us of other parties' trademarks, trade dress or products is not intended to and does not imply a relationship with, or endorsements or sponsorship of, us by the trademark or trade dress owner.

Unless the context requires otherwise, references in this Quarterly Report on Form 10-Q to "Zogenix," "we," "us" and "our" refer to Zogenix, Inc., including, as of June 7, 2010, its consolidated subsidiary.

The interim consolidated financial statements and this Management's Discussion and Analysis of Financial Condition and Results of Operations should be read in conjunction with the consolidated financial statements and notes thereto for the year ended December 31, 2011 and the related Management's Discussion and Analysis of Financial Condition and Results of Operations, both of which are contained in our Annual Report on Form 10-K for the year ended December 31, 2011.

Background

We are a pharmaceutical company commercializing and developing products for the treatment of central nervous system disorders and pain. Our first commercial product, Sumavel DosePro (sumatriptan injection) Needle-free Delivery System, offers fast-acting, easy-to-use, needle-free subcutaneous administration of sumatriptan for the acute treatment of migraine and cluster headache in a pre-filled, single-use delivery system. We launched the commercial sale of Sumavel DosePro in the United States in January 2010 with our co-promotion partner, Astellas Pharma US, Inc., or Astellas. Our sales and marketing organization is comprised of approximately 115 professionals. Our field sales force of approximately 95 representatives has historically promoted Sumavel DosePro primarily to neurologists and other prescribers of migraine medications, including headache clinics and headache specialists. Our promotional efforts have been complemented by our collaboration with Astellas and approximately 400 of its sales representatives, who have promoted Sumavel DosePro primarily to primary care physicians, OB/GYNs, emergency medicine physicians and urologists in the United States. Our collaboration with Astellas terminated on March 31, 2012, at which time we assumed full responsibility for the commercialization of Sumavel DosePro. During the first quarter of 2012, we began to assume responsibility from Astellas for marketing Sumavel DosePro to selected high-prescribing primary care physicians and other Astellas-targeted physicians and professionals within the Astellas Segment pursuant to a promotion transition plan. We are currently evaluating potential co-promotion partners who could complement our sales force efforts for the commercial sale of Sumavel DosePro. We also have entered into a partnership for Sumavel DosePro with Desitin Arzneimittel GmbH, or Desitin, to accelerate development and regulatory approvals in Europe and further enhance the global commercial potential of Sumavel DosePro.

On May 1, 2012, we submitted a New Drug Application, or NDA, to the U.S. Food and Drug Administration, or FDA, for our lead product candidate, Zohydro (hydrocodone bitartrate). Zohydro is a 12-hour extended-release formulation of hydrocodone without acetaminophen for the treatment of moderate to severe chronic pain requiring around-the-clock opioid therapy. We completed Phase 3 development of Zohydro in 2011, and we in-licensed exclusive U.S. rights to Zohydro from Alkermes plc (formerly Elan Pharma International Limited) in 2007.

In March 2012, we entered into a co-marketing and option agreement with Battelle Memorial Institute, or Battelle, to accelerate the out-licensing efforts of our DosePro drug delivery technology. Under this co-marketing and option agreement, Battelle will have the exclusive right to co-market our DosePro drug delivery technology to a specified list of Battelle's pharmaceutical clients. In addition, we granted Battelle the option to enter into an exclusive co-development and commercialization agreement with us related to our 1.2 mL DosePro drug delivery technology.

In July 2011, we entered into a development and license agreement with Durect Corporation, or the Relday license agreement, pursuant to which we will be responsible for the clinical development and commercialization of Relday, a proprietary, long-acting injectable formulation of risperidone using Durect's SABER™ controlled-release formulation technology in combination with our DosePro needle-free, subcutaneous drug delivery system. Risperidone is used to treat the symptoms of schizophrenia and bipolar disorder in adults and teenagers 13 years of age and older. Relday will be developed to address unmet clinical needs in this patient population and is being developed to be a once-monthly, subcutaneous antipsychotic product. We expect to initiate clinical studies for the new product candidate in patients with schizophrenia in 2012 following filing of an investigational new drug application in the second quarter of 2012.

We have experienced net losses and negative cash flow from operating activities since inception, and as of March 31, 2012, had an accumulated deficit of $292.3 million. We expect to continue to incur net losses and negative cash flow from operating activities for at least the next several years primarily as a result of the expenses incurred in connection with our regulatory filings for Zohydro, the initiation of clinical development for Relay, any additional required testing for Zohydro, and the cost of the sales and marketing expense associated with Sumavel DosePro, and, if approved, Zohydro. As of March 31, 2012, we had cash and cash equivalents of $39.8 million. Although it is difficult to predict future liquidity requirements, we believe that our cash and cash equivalents as of March 31, 2012, estimated future product revenues and borrowings available under our $10.0 million revolving credit facility, will be sufficient to fund our operations into the first quarter of 2013. We will need to obtain additional capital to finance our operations beyond that point. We intend to raise additional capital through debt or equity financings or through collaborations or partnerships with other companies. If we are not able to raise additional capital on terms acceptable to us, or at all, as and when needed, we may be

required to reduce or curtail our operations and costs, and we may be unable to continue as a going concern. In its report on our consolidated financial statements for the year ended December 31, 2011, our independent registered public accounting firm included an explanatory paragraph expressing substantial doubt regarding our ability to continue as a going concern.

Astellas Co-Promotion Agreement

Under our co-promotion agreement with Astellas that we entered into in July 2009, or the co-promotion agreement, Astellas primarily promoted Sumavel DosePro to primary care physicians (including internal medicine, family practice and general practice), OB/GYNs, emergency medicine physicians and urologists, or collectively, the Astellas Segment, in the United States. Our sales force historically promoted Sumavel DosePro primarily to neurologists and other key prescribers of migraine medications, including headache clinics and headache specialists in the United States. We jointly shared in the cost of advertising, marketing and other promotional activities related to the Sumavel DosePro brand and were required to provide minimum levels of sales effort to promote Sumavel DosePro. In December 2011, we entered into an amendment to the co-promotion agreement with Astellas, or the amended co-promotion agreement, whereby the agreement terminated on March 31, 2012.

Under the terms of the amended co-promotion agreement, we will be required to make two annual tail payments to Astellas, estimated as a total of $5.5 million, calculated as decreasing fixed percentages (ranging from a mid-twenties down to a mid-teen percentage) of net sales in the Astellas Segment in the last 12 months of its active promotion. The present value of such tail payments was recorded as a long-term liability on the amendment date and is payable in July 2013 and July 2014. The fair value of the tail payments will be accreted through interest expense on a monthly basis through the date of payment. As of March 31, 2012, the long-term tail payment liability was $4.3 million, net of the discount, and there was $0.2 million of related interest expense recognized during the three months ended March 31, 2012. Additionally, beginning in the second quarter of 2012, our sales force assumed full responsibility for the continued marketing of Sumavel DosePro, expanding our focus to include a portion of the high-prescribing primary care physicians previously covered by Astellas under the co-promotion agreement. We expect to seek another co-promotion partner to compliment our sales to promote Sumavel DosePro, if available.

At the inception of the co-promotion agreement and in exchange for the right to promote Sumavel DosePro, Astellas made a non-refundable up-front payment of $2.0 million to us and made an additional $18.0 million of payments to us upon the achievement of a series of milestones. These proceeds are reflected as $8.5 million of deferred revenues on our consolidated balance sheet at December 31, 2011. Beginning with the launch of Sumavel DosePro in January 2010, we began recognizing these proceeds as contract revenues on a ratable basis over 42 months (the original term of the agreement). Upon amendment of the co-promotion agreement on December 20, 2011, the remaining deferred proceeds were recognized as contract revenues on a ratable basis over 3.4 months (the remaining term of the amended agreement). This acceleration in the recognition of the contract proceeds resulted in the recognition of $8.5 million of contract revenue during the three months ended March 31, 2012.

In consideration for Astellas' performance of its commercial efforts, we were required to pay Astellas a service fee on a quarterly basis that represents a fixed percentage of between 45% and 55% of Sumavel DosePro net sales to the Astellas Segment through the date of termination. Astellas paid us a fixed fee for all sample units they ordered for distribution to their sales force. Amounts received from Astellas for shared marketing costs and sample product are reflected as a reduction of selling, general and administrative expenses, and amounts payable to Astellas for shared marketing expenses and service fees are reflected as selling, general and administrative expenses. For the three months ended March 31, 2012 and 2011, we incurred $1.7 million and $1.5 million, respectively, in service fee expenses. For the three months ended March 31, 2012 and 2011, we recognized shared marketing expense of $0.3 million and $0.4 million, respectively.

We record the revenues related to all products sales, including sales generated by the Astellas sales force. Consequently, we record cost of sales for all product sales. For the three months ended March 31, 2012 and 2011, the Astellas Segment represented approximately 31% and 40%, respectively, of our prescription demand.

Based on third-party data, approximately 86% of the prescription demand in the Astellas Segment was concentrated to a population of approximately 500 physicians, which we believe our sales force will be able to support after our transition plan utilizing our Phase IV data, toolbox and other promotional activities. As such, we do not expect that all of the prescription demand contributed by the Astellas sales force will be foregone as a result of the early termination of the co-promotion agreement. However, in the event we are unsuccessful in transitioning the Astellas Segment to our sales force, our net product sales and financial results could be negatively impacted.

Revenues

For the three months ended March 31, 2012 and 2011 we recognized $9.9 million and $7.5 million, respectively, in net product revenues. For the three months ended March 31, 2012 and 2011 we recognized $8.5 million and $1.6 million, respectively, in contract revenues associated with license and milestone payments made to us by Astellas under the co-promotion agreement.

We sell Sumavel DosePro product in the United States to wholesale pharmaceutical distributors and retail pharmacies, or collectively, our customers, subject to rights of return. Prior to the third quarter of 2011, Sumavel DosePro had a limited sales history, and we could not reliably estimate expected returns of the product at the time of shipment. Accordingly, we deferred recognition of revenue on product shipments of Sumavel DosePro until the right of return no longer existed, which occurred at the earlier of the time Sumavel DosePro units were dispensed through patient prescriptions or expiration of the right of return. Units dispensed are generally not subject to return, except in the rare cases where the product malfunctions or the product is damaged in transit. We estimate patient prescriptions dispensed using an analysis of third-party information, including third-party market research data.

Beginning in the third quarter of 2011, we began recognizing Sumavel DosePro product sales at the time title transfers to our customer, and providing for an estimate of future product returns at that time. We believe that our estimated product return allowances for Sumavel DosePro require a high degree of judgment and are subject to change based on our experience and certain quantitative and qualitative factors. Sumavel DosePro currently has a shelf life of 24 months from the date of manufacture. We accept unused product from our customers that are within six months before and up to one year after its expiration date for a credit at the then-current whole acquisition cost, or WAC, reduced by a nominal fee for processing the return. Our initial product inventories reached expiration in 2011.

We have monitored actual return history on an individual product lot basis since product launch. Actual product return experience in 2011 included a disproportionately high amount of returns from a single retail chain. In addition, we have also experienced a high level of returned product from our initial launch stocking initiatives. We may experience higher levels of returns upon the termination of the co-promotion agreement with Astellas on March 31, 2012 due to fall-off of prescription demand in territories that may no longer be supported with direct promotional efforts. We consider these factors as well as the dating of our product at the time of shipment into the distribution channel, prescription trends and changes in the estimated levels of inventory within the distribution channel to estimate our exposure for returned product. Because of the shelf life of Sumavel DosePro and our return policy of issuing credits on returned product that is within six months before and up to one year after its product expiration date, there may be a significant period of time between when the product is shipped and when we issue credits on returned product. Accordingly, we may have to adjust these estimates, which could have an effect on product sales and earnings in the period of adjustments. A 1% increase or decrease in our returns reserve as a percentage of product shipped in the first quarter of 2012 would have a cumulative financial statement impact of approximately $0.1 million for the three months ended March 31, 2012.

We permit certain wholesale pharmaceutical distributors to purchase limited quantities of product after the announcement of an increase to the WAC of our product and prior to the effectiveness of the increase. In turn, WAC price increases can result in accelerated purchases by wholesalers relative to anticipated retail and prescription demand. The timing of purchases made by wholesale distributors and retail pharmacies are subject to fluctuations for these reasons among others. Absent accelerated purchasing by wholesalers or other periodic changes in buying patterns, the wholesale channel has historically contained two to three weeks of product on hand. As of March 31, 2012, wholesale distributors reported approximately three weeks of our product on hand.

Cost of Sales

Cost of sales consist primarily of materials, third-party manufacturing costs, freight and indirect personnel and other overhead costs associated with sales of Sumavel DosePro based on units dispensed through patient prescriptions, as well as reserves for excess, dated or obsolete commercial inventories and production manufacturing variances. For the three months ended March 31, 2012 and 2011, our cost of sales was $5.1 million and $4.9 million, respectively. Our product gross margin for the three months ended March 31, 2012 and 2011 was 49% and 35%, respectively.

Royalty Expense

Royalty expense consists of the amortization of the $4.0 million milestone payment paid by us to Aradigm Corporation upon the first commercial sale of Sumavel DosePro in the United States (which occurred in January 2010) and royalties payable to Aradigm based on net sales of Sumavel DosePro by us or one of our licensees. We are not required to make any further milestone payments to Aradigm. Our ongoing royalty obligation payable to Aradigm is set forth in the asset purchase agreement we entered into with Aradigm in August 2006 pursuant to which we acquired the rights to the DosePro technology. During the three months ended March 31, 2012 and 2011, we incurred $0.4 million and $0.3 million, respectively, in royalty expense to Aradigm.

Research and Development Expenses

Our research and development expenses consist of expenses incurred in developing, testing and seeking marketing approval of our product candidates, including:

• payments made to Durect for the license to and further development of Relday;

• milestone payments made to Alkermes in connection with development and regulatory milestones of Zohdyro;

• payments made to third-party contract research organizations, or CROs, and investigational sites, which conduct our trials on our behalf, and consultants;

• expenses associated with regulatory submissions, pre-clinical development and clinical trials;

• payments to third-party manufacturers, which produce our active pharmaceutical ingredient and finished product;

• payments made to third-party CROs, laboratories and consultants in connection with pre-clinical studies;

• personnel related expenses, such as salaries, benefits, travel and other related expenses, including stock-based compensation; and

• facility, maintenance, depreciation and other related expenses.

We expense all research and development costs as incurred.

In March 2010, we initiated our Phase 3 clinical development program for Zohydro. We utilize CROs, contract laboratories and independent contractors for the conduct of pre-clinical studies and clinical trials. In 2010, we began tracking third party costs by type of study being conducted. We recognize the expenses associated with the services provided by CROs based on the percentage of each study completed at the end of each reporting period. We coordinate clinical trials through a number of contracted investigational sites and recognize the associated expense based on a number of factors, including actual and estimated subject enrollment and visits, direct pass-through costs and other clinical site fees. For the three months ended March 31, 2012 and 2011, we incurred $3.0 million and $6.5 million in third party research and development costs related to Zohydro, respectively.

Relday is currently in the pre-clinical development phase and we plan to initiate clinical development of Relday in 2012. We recognize the costs of pre-clinical work as it is performed. Under the Relday license agreement, Durect is responsible for non-clinical, formulation, chemistry, and manufacturing and controls development for Relday. We paid a non-refundable upfront fee to Durect of $2.25 million in July 2011. In addition, we incurred $1.1 million in research and development costs payable to Durect during the three months ended March 31, 2012.

We use our employee and infrastructure resources across our product and product candidate development programs. Therefore, we have not tracked salaries, other personnel related expenses, facilities or other related costs to our product development activities on a program-by-program basis. The following table illustrates, for each period presented, our research and development costs broken down by our major development programs, as well as other expenses not tracked on a program-by-program basis, as described above, and expenses associated with all other product candidates:

                                               Three Months Ended March 31,
                                                 2012                2011
                                                      (In Thousands)
        Research and development expenses:
        Zohydro                              $       3,045       $       6,499
        Relday                                       1,329                 503
        Sumavel DosePro                                142                  92
        Other (1)                                    1,448               1,430

        Total                                $       5,964       $       8,524

(1) Other research and development expenses include development costs incurred for the DosePro technology sound enhancement and other product candidate development, as well as employee and infrastructure resources that are not tracked on a program-by-program basis.

We expect our research and development costs for 2012 to decrease over amounts incurred in 2011 as we completed the Phase 3 clinical trials for Zohydro in December 2011. We are obligated to pay Alkermes a $1.0 million milestone payment in the second quarter of 2012 in connection with the submission of the NDA for Zohydro to the FDA. We may be obligated to pay Alkermes up to

$2.75 million in total additional future milestone payments with respect to Zohydro depending upon the achievement of other various development and regulatory events. These future milestone payments include a payment of $0.8 million upon successful completion of an FDA pre-approval inspection of our manufacturing facility. If Zohydro is approved, we are also required to pay a mid single-digit percentage royalty on its net sales for a specified period of time and continue to pay royalties on net sales of the product thereafter at a reduced low single-digit percentage rate in accordance with the terms of the license agreement.

While we submitted an NDA for Zohydro with the FDA early in the second quarter of 2012, the successful development and commercialization of Zohydro is highly uncertain. We also expect to incur customary regulatory costs associated with the NDA, which will be significant. If Zohydro is approved, we also expect to incur significant expenses related to manufacturing and marketing activities. However, at this time, we cannot reasonably estimate or know the nature, . . .