The purpose of this study is to evaluate whether the DMTS, compared with a placebo patch, will provide adequate pain relief during the first 3 days following bunionectomy surgery.

The primary objective of this study is to evaluate the analgesic efficacy of the DMTS, compared with placebo in subjects with acute moderate to severe pain following unilateral bunionectomy.

The secondary objectives are:

• To assess the safety and tolerability of the DMTS, including assessment of skin irritation
• To assess adhesion of the DMTS
• To assess the sedation effect of the DMTS

Inclusion Criteria:

1. Voluntarily provide written informed consent.

2. Male or female, ≥ 18 years of age.

3. Scheduled to undergo a primary unilateral first metatarsal bunionectomy repair.

4. Have a physical status classification of 1 or 2 per the American Society of Anesthesiology.

5. Non-smoker for at least 1 year prior to screening; non-smoking is defined by cessation of smoking and use of all other tobacco and nicotine products (including chewing tobacco, snuff, e-cigarettes, nicotine patches, etc.).

6. Female subjects are eligible only if all the following apply:

   1. Not pregnant, not lactating, and not planning to become pregnant during the study
   2. Surgically sterile; or at least 2 years postmenopausal; or have a monogamous partner who is surgically sterile; or have a same gender sex partner; or is practicing double-barrier contraception; or practicing abstinence; or using an insertable, injectable, transdermal, or combination oral contraceptive

7. Male subjects with female sex partners must be surgically sterile or commit to the use of a reliable method of birth control.

8. Have a body weight > 50 kg, and body mass index of 22 to 38 kg/m2, inclusive.

9. Able to understand the study procedures, comply with all study procedures, and agree to participate in the study program for its full duration.

Exclusion Criteria:

1. Have a known sensitivity to dexmedetomidine or any excipient in the DMTS/placebo or to any peri- or postoperative medication whose use is required in this study.
2. Have a skin abnormality (eg, scar, tattoo) or unhealthy skin condition (eg, burns, wounds) at the patch application site, according to examination by the investigator at screening or admission to the clinic prior to surgery.
3. Have a clinically significant abnormal clinical laboratory test value.
4. Have history of or positive test results for the human immunodeficiency virus (HIV), hepatitis B, or hepatitis C.
5. Have a history or clinical manifestations of: a significant renal, hepatic, cardiovascular, metabolic, neurologic, or psychiatric condition; congestive heart failure, peptic ulcer, gastrointestinal bleeding, or other condition that would preclude participation in the study.
6. Have a history of migraine or frequent headaches, seizures, or are currently taking anticonvulsants.
7. Have another painful physical condition that may confound the assessments of postoperative pain.
8. Have a history of syncope or other syncopal attacks.
9. Have evidence of a clinically significant 12-lead ECG abnormality.
10. Have a history of alcohol abuse or prescription/illicit drug abuse.
11. Have positive results on the urine drug screen or alcohol breath test indicative of illicit drug or alcohol use at screening and/or clinic check-in.
12. Have a history or evidence of clinically significant orthostatic hypotension.
13. Have a resting heart rate of < 50 beats per minute or systolic blood pressure < 100 mmHg.
14. Have been receiving or have received opioid therapy chronically for > 2 weeks within the month prior to dosing of the study drug.
15. Use concurrent therapy that could interfere with the evaluation of efficacy or safety, such as any drugs which in the investigator's opinion may exert significant analgesic properties or act synergistically with dexmedetomidine.
16. Have had an upper respiratory tract infection within 14 days prior to dosing of the study drug.
17. Have utilized oral or injectable corticosteroids within 14 days prior to dosing of the study drug (intranasal and topical corticosteroid use during this time period is allowed).
18. Have received any investigational product within 30 days prior to dosing of the study drug.
19. Have previously received DMTS in a clinical trial.
20. Sensitivity to opioids, nonsteroidal anti-inflammatory drugs, or antibiotics.
21. In the opinion of the investigator or designee, is considered unsuitable for study entry and/or is unlikely to comply with the study protocol for any reason.