Conditions: Cough Reflex Sensitivity
Keywords: cough cough reflex capsaicin diphenhydramine phenylephrine dextromethorphan placebo
Allocation: RANDOMIZED | Intervention model: CROSSOVER
Enrollment: 22
Healthy volunteers: no

Brief summary:
The purpose of this study is to evaluate the antitussive (cough-suppressing) effects of two liquid medications: a combination of diphenhydramine and phenylephrine in a naturally cocoa flavoring, and, dextromethorphan syrup, compared with placebo.

Detailed description:

Arms:
arm 1: 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. arm 2: 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. arm 3: 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. arm 4: 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. arm 5: 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. arm 6: 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.

Interventions: intervention 1: diphenhydramine/phenylephrine/cocoa; dextromethorophan; placebo intervention 2: diphenhydramine/phenylephrine/cocoa; placebo; dextromethorphan intervention 3: dextromethorphan; diphenhydramine/phenylephrine/cocoa; placebo intervention 4: dextromethorophan; placebo; diphenhydramine/phenylephrine/cocoa intervention 5: placebo; diphenhydramine/phenylephrine/cocoa; dextromethorphan intervention 6: placebo; dextromethorphan; diphenhydramine/phenylephrine/cocoa
Intervention descriptions: intervention 1: diphenhydramine 25 mg and phenylephrine 10 mg; dextromethorphan 30 mg; placebo. intervention 2: diphenhydramine 25 mg and phenylephrine 10 mg; placebo; dextromethorphan 30 mg. intervention 3: dextromethorphan 30 mg; diphenhydramine 25 mg and phenylephrine 10 mg; placebo intervention 4: dextromethorphan 30 mg; placebo; diphenhydramine 25 mg and phenylephrine 10 mg intervention 5: placebo; diphenhydramine 25 mg and phenylephrine 10 mg; dextromethorphan 30 mg intervention 6: placebo; dextromethorphan 30 mg; diphenhydramine 25 mg and phenylephrine 10 mg

Protocol document: