Overview

Differential Adrenoreceptor Mediated Tachyphylaxis and Upregulation

Status:
Completed
Trial end date:
2009-05-01
Target enrollment:
0
Participant gender:
All
Summary
The investigators wish to evaluate the onset of tolerance to nasal decongestants like oxymetazoline (available over the counter) and the mechanism of tolerance particularly with differential effects on alpha 1 and alpha 2 adrenoreceptors on the nose. The investigators will 'tease' out by using an alpha 1 blocker called Prazosin. The investigators hypothesize that alpha 1 receptors mediate arterial constriction and this will be captured by measuring nasal blood flow. The investigators also hypothesize that alpha 2 receptors mediate venous sinusoid constriction and this the investigators will capture by airflow parameters like Peak Nasal Inspiratory Flow, Rhinomanometry, Oscillometric indices etc.
Phase:
Phase 4
Accepts Healthy Volunteers?
Accepts Healthy Volunteers
Details
Lead Sponsor:
Brian J Lipworth
Treatments:
Fluticasone
Oxymetazoline
Phenylephrine
Prazosin
Xhance
Criteria
Inclusion Criteria:

- Male of Female aged 18-65 years.

- Healthy volunteers with a negative history of seasonal or perennial nasal symptoms
other than occasional common colds. Atopy will not preclude inclusion into the study
as long as patients have no nasal symptoms.

- Current non-smokers (ex-smokers for greater than 6 months duration with a total
smoking history of less than 5 pack-years will be eligible).

- PNIF > 100L/min (best effort of 3) and reversibility with OXY 2 squirts in each
nostril (20 min reading) > 20 L/min.

- Ability to give a written informed consent.

- Ability and willingness to comply with the requirements of the protocol.

Exclusion Criteria:

- Recent respiratory tract/sinus infection within the last 2 months.

- Pregnancy, planned pregnancy or lactation.

- Known or suspected hypersensitivity to any of the IMP's.

- Concomitant use of medicines (prescribed, OTC or herbal) like alpha blockers that may
interfere with the trial.