A Pilot Study to Increase Take-up of Overdose Reversal Drugs

Last registered on May 17, 2021


Trial Information

General Information

A Pilot Study to Increase Take-up of Overdose Reversal Drugs
Initial registration date
March 31, 2020

Initial registration date is when the trial was registered.

It corresponds to when the registration was submitted to the Registry to be reviewed for publication.

First published
March 31, 2020, 3:11 PM EDT

First published corresponds to when the trial was first made public on the Registry after being reviewed.

Last updated
May 17, 2021, 11:29 PM EDT

Last updated is the most recent time when changes to the trial's registration were published.



Primary Investigator


Other Primary Investigator(s)

PI Affiliation

Additional Trial Information

In development
Start date
End date
Secondary IDs
Despite widespread public attention to the opioid epidemic and numerous policies to prevent opioid misuse, overdose deaths in the United States increased 16 percent per annum between 2014 and 2017. Public health authorities consider naloxone, a prescription opioid-overdose reversal drug, a key strategy to stemming the tide of overdose deaths and recommend dispensing the medication along with high-dose opioid prescriptions. Nonetheless, naloxone take-up remains low. In collaboration with an online pharmacy platform licensed to dispense naloxone in many states, we will use an online advertising campaign to pilot test approaches to increasing naloxone purchases. Randomizing advertisements across counties, we will measure how traffic to the pharmacy site and naloxone purchases respond to purchase price and information content, including how salient the ads make stigma. We will also consider the impact of advertising more generally. This pilot will be used to scale up to a study that sheds light on both the price elasticity of demand for naloxone and potential non-price barriers to take-up.
External Link(s)

Registration Citation

Jacobson, Mireille and David Powell. 2021. "A Pilot Study to Increase Take-up of Overdose Reversal Drugs." AEA RCT Registry. May 17. https://doi.org/10.1257/rct.5333-2.0
Sponsors & Partners

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Experimental Details


In partnership with an online naloxone distributor, we will test the importance of price and information (including stigma) in deterring access to naloxone. More specifically, we will implement randomized experiments (via Google Ads) for multiple concurrent interventions related to price, and information. We will monitor ad exposure (or impressions), clicks or traffic driven to the exchange site by different types of advertisements, and subsequent purchases. Google Analytics will also be used to track clicks and purchases made from counties that are randomized to receive no ads.
Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
naloxone doses purchases
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
ad impressions; ad clicks; website visits; revenue
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
We will run concurrent experiments through the Google Adwords platform to randomize ads that address information gaps and/or stigma issues that may be barriers to the take-up of naloxone. We exclude counties in which the online naloxone distributor is not selling naloxone (as of March 31, 2020).

Randomization will occur at the county level. We will also randomly allocate counties to a control arm that receives no advertising from us. Across our treatment conditions, we will further randomize the advertised (and thereby offered) price of naloxone. In the end, we have 5 approximately equally-sized groups of counties.

Using 2018 overdose data, we constructed the opioid overdose rate for each county as well as indicators for each quintile of the opioid overdose distribution. To improve balance on these metrics, we re-randomized until all 5 experimental arms were within 0.5 opioid overdoses per 100,000 of each other and the distributions were similar as well (for each quintile, no arm is more than 10 percentage points larger than any other arm).
Experimental Design Details
Randomization Method
In office by computer
Randomization Unit
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
2354 counties
Sample size: planned number of observations
4500 clicks
Sample size (or number of clusters) by treatment arms
1500 clicks per treatment condition
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
At present, we have proposed 1500 clicks per treatment condition, divided within each condition by prices of $20 and $110. These choices were chosen with the budget constraint in mind. Across the two price points of $110 and $20, we will have 2250 clicks. Assuming a baseline conversion rate of just 5%, 2250 clicks with the $20 coupon would allow us to detect an increase in purchases of 1.8 percentage points or 36%.
Supporting Documents and Materials


Document Name
IRB - Not Human Subjects
Document Type
Document Description
USC IRB determined that this protocol is not human subjects.
IRB - Not Human Subjects

MD5: ec5ccfe319b54a1f9c2fd41edf5ab142

SHA1: b1e3706f5d82f067430920a3773c19c3d959cd41

Uploaded At: January 21, 2020


Institutional Review Boards (IRBs)

IRB Name
University of Southern California
IRB Approval Date
IRB Approval Number
HS-19-00953: Deemed not human subjects
Analysis Plan

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Post Trial Information

Study Withdrawal

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Is the intervention completed?
Data Collection Complete
Data Publication

Data Publication

Is public data available?

Program Files

Program Files
Reports, Papers & Other Materials

Relevant Paper(s)

Reports & Other Materials