Please assess the completion status of the following clinical trial:

Trial Title: Antitussive Effect of a Naturally Flavored Syrup Containing Diphenhydramine, Compared With Dextromethorphan and Placebo

Study Design Characteristics:
- Allocation: RANDOMIZED
- Intervention Model: CROSSOVER
- Observational Model: None
- Primary Purpose: TREATMENT
- Time Perspective: None
- Masking: DOUBLE
- Phase: PHASE4
- Number of Arms: 6.0

Eligibility Criteria:
Inclusion Criteria:~* healthy adult nonsmokers~* onset of acute, viral upper respiratory tract infection (common cold) within 72 hours of enrollment~Exclusion Criteria:~* smokers~* history of asthma or other respiratory disorders

- Gender: ALL
- Minimum Age: 18 Years
- Maximum Age: None
- Healthy Volunteers: f

Study Arms:
- A, B, then C (Type: EXPERIMENTAL): Subjects received the following: Period 1: single oral dose of diphenhydramine 25 mg and phenylephrine 10 mg, in naturally-flavored cocoa syrup (treatment A). Period 2: dextromethorphan syrup 30 mg (treatment B); Period 3: placebo liquid, dextrose in water, 20 mL (treatment C).~Intervention: capsaicin cough challenge testing 2 hours after study drug ingestion.Each dosing period separated by 1-2 day washout period.
- A, C, then B (Type: EXPERIMENTAL): Subjects received the following: Period 1: single oral doce of diphenhydramine 25 mg and phenylephrine 10 mg, in naturally-flavored cocoa syrup (treatment A); Period 2: placebo liquid, dextrose in watwer, 20 mL (treatment C); Period 3: dextromethorphan syrup 30 mg (treatment B).~Intervention: capsaicin cough challenge testing 2 hours after study drug ingestion.Each dosing period separated by 1-2 day washout period.
- B, A, then C (Type: EXPERIMENTAL): Subjects received the following: Period 1: dextromethorphan syrup 30 mg (treatment B); Period 2: single dose of oral diphenhydramine 25 mg and phenylephrine 10 mg, in a naturally-flavored cocoa syrup (treatment A); Period 3: placebo liquid, dextrose in water, 20 mL (treatment C). Intervention: capsaicin cough challenge testing 2 hours after study drug ingestion. Each dosing period separated by 1-2 day washout period.
- B, C, then A (Type: EXPERIMENTAL): Subjects received the following: Period 1: dextromethorphan 30 mg syrup (treatment B); Period 2: placebo liquid, dextrose in water, 20 mL (treatment C); Period 3: single dose of oral diphenhydramine 25 mg and phenylephrine 10 mg in a naturally-flavored cocoa syrup (treatment A).~Intervention: capsaicin cough challenge testing 2 hours after study drug ingestion. Each dosing period separated by 1-2 day washout period.
- C, A, then B (Type: EXPERIMENTAL): Subjects received the following: Period 1: placebo liquid, dextrose in water, 20 mL (treatment C); Period 2: a single oral dose of diphenhydramine 25 mg and phenylephrine 10 mg in a naturally-flavored cocoa syrup (treatment A); Period 3: dextromethorphan 30 mg syrup (treatment B). Intervention: capsaicin cough challenge testing 2 hours after study drug ingestion. Each dosing period separated by 1-2 day washout period.
- C, B, then A (Type: EXPERIMENTAL): Subjects received the following: Period 1: placebo liquid, dextrose in water, 20 mL (treatment C); Period 2: dextromethorphan 30 mg syrup (treatment B); Period 3: a single oral dose of diphenhydramine 25 mg and phenylephrine 10 mg in a naturally-flavored cocoa syrup (treatment A). Intervention: capsaicin cough challenge testing 2 hours after study drug ingestion. Each dosing period separated by 1-2 day washout period.

Based on this trial design, predict the completion outcome and termination type (if applicable).

Answer: outcome: complete