“Efficacy and Safety of Phlai Capsule Compared to Placebo as the Treatment in Allergic Rhinitis Patients”


Background: Zingiber cassumunar Roxb., frequently known as Phlai in Thai, has been safely used as an antihistaminic and anti-inflammatory drug in Thai traditional medicine. Individual with allergic rhinitis may have positive response to Phlai.

Objective: Investigators assessed the efficacy and safety of Phlai as a treatment for allergic rhinitis Design: The study was a 1-month, double-blind, randomized, parallel-group, intent-to-treat, multicenter, controlled trial in 267 patients at 7 hospitals in Thailand. Skin prick test-positive adults with allergic rhinitis ages 18 to 50 who were randomized into 3 groups (Phlai 8mg/d, Phlai 4mg/d, placebo).

Main outcome measures: Primary outcome was defined: improvement of total 5 symptoms scores (nasal obstruction, rhinorrhea, sneezing, itchy nose, itchy eyes) over a 4-week interval among Phlai 8mg/d, Phlai 4mg/d and placebo. Secondary endpoints were: assessments of rhinoconjunctivitis quality of life questionnaire, peak inspiratory nasal flow, nasal examination, adverse events, AST, ALT, Creatinine and BUN over a period of 4 weeks.

Full Title of Study: “”Efficacy and Safety of Phlai Capsule Compared to Placebo as the Treatment in Allergic Rhinitis Patients”"

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: Randomized
    • Intervention Model: Parallel Assignment
    • Primary Purpose: Treatment
    • Masking: Double (Participant, Care Provider)
  • Study Primary Completion Date: November 2021


  • Drug: Phlai
    • Each capsule contains 4 mg compound D. Using orally in the evening everyday in 4 weeks
  • Drug: Placebo oral capsule
    • Like Phlai capsule extract : :PVP K30, Calcium carbonate, Dibasic calcium phosphate, Sodium starch glycolate, Colloidal silicon dioxide, Ethanol 96%, Purified water, Magnesium stearate. Not having compound D. Using orally in the evening everyday in 4 weeks

Arms, Groups and Cohorts

  • Experimental: Arm 1
    • Phlai 2 capsules (compound D 8 mg) od evening after meal x 4 weeks
  • Experimental: Arm 2
    • Phlai 1 capsules (compound D 4 mg) and placebo 1 capsule od evening after meal x 4 weeks
  • Placebo Comparator: Arm 3
    • Placebo 2 capsules od evening after meal x 4 weeks

Clinical Trial Outcome Measures

Primary Measures

  • Total five symptoms score (T5SS)
    • Time Frame: 24 hours
    • T5SS: (nasal obstruction, rhinorrhea, sneezing, itchy nose, itchy eyes). For each symptom: 0: no symptoms mild moderate severe. Participants assess T5SS everyday. Self assessment twice a day Bedtime : reflective symptoms score Morning :instantaneous symptoms score. The mean score of two assessment is the T5SS. Investigator will calculate the mean T5SS in the follow up

Secondary Measures

  • Rhinoconjunctivitis Quality of Life Questionaire (RCQ-36) Thai version
    • Time Frame: 4 weeks
    • This questionnaire is designed to find out how your health and well-being have been affected by rhinoconjunctivitis.
  • Peak inspiratory nasal flow (PNIF)
    • Time Frame: 2 weeks
    • Use to measure nasal airflow during maximal inspiration
  • Nasal examination
    • Time Frame: 2 weeks
    • Outcome assessor in each site will check the three symptoms: nasal swelling, pale and nasal discharge by anterior rhinoscopy
  • Adverse events
    • Time Frame: 2 weeks
    • Sedation, dizziness, dry mouth, headache
  • AST Level
    • Time Frame: 4 weeks
    • Liver function test
  • ALT Level
    • Time Frame: 4 weeks
    • Liver function test
  • Creatinine level
    • Time Frame: 4 weeks
    • Renal function test
  • BUN
    • Time Frame: 4 weeks
    • Renal function test
  • Eosinophils blood level
    • Time Frame: 4 weeks
    • CBC test
  • Lymphocyte blood level
    • Time Frame: 4 weeks
    • CBC test
  • Hemoglobin
    • Time Frame: 4 weeks
    • CBC test
  • Platelet level
    • Time Frame: 4 weeks
    • CBC test

Participating in This Clinical Trial

Inclusion Criteria

  • Age 18-50 years old
  • Allergic rhinitis following diagnostic criteria of ARIA guideline
  • Reflective total 5 symptoms score 2-10 per day for 3 consecutive days (total score=15) and not greater than 10 in any days during the past week
  • Positive skin prick test to at least one aeroallergen: wheal size ≥ 3 mm greater than negative control
  • Not receiving intranasal corticosteroid + intra antihistamine for 2 weeks , intranasal corticosteroid for 2 weeks, systemic corticosteroid for 4 weeks, antihistamine for 1 week, nasal decongestant for 1 week and leukotriene receptor antagonists for 1 week

Exclusion Criteria

  • Serious medical underlying diseases e.g. COPD, Heart disease, Chronic renal failure, chronic hepatic failure
  • Allergic rhinitis and asthma which require immunotherapy
  • Receiving antidepressants, sedative, anxiolytic, opioids, neuroleptic
  • Uncontrolled asthma which requires steroid inhaler, LABA and does not use leukotriene receptor antagonists
  • Previous nasal surgery for nasal polyp, nasal septum deviation
  • Acute or chronic rhinosinusitis
  • Pregnancy and lactation (Urine pregnancy test is allowed and paid by researchers)
  • Allergic to any kinds of herb
  • Refusal to participation

Gender Eligibility: All

Minimum Age: 18 Years

Maximum Age: 50 Years

Are Healthy Volunteers Accepted: Accepts Healthy Volunteers

Investigator Details

  • Lead Sponsor
    • Chulalongkorn University
  • Collaborator
    • Government Pharmaceutical Organization
  • Provider of Information About this Clinical Study
    • Principal Investigator: Minh Phuoc Hoang, MD, Principal Investigator – Chulalongkorn University
  • Overall Contact(s)
    • Minh P. Hoang, Master, 0946148133, minhphuochoang@gmail.com

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