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Mefloquine Hydrochloride

Methanolquinolines · given by oral · on the market since 2002

5
Leads
21.6M
People
2
Makers
9
How abandoned
01

What it's made of

Each functional group on the molecule does a specific, predictable job.

SETS WHERE IT GOES

Basic amine

What it does. Neutral enough to slip through membranes, then becomes charged inside the acidic compartments of the cell and gets trapped there. Concentrations inside cells can reach many times the blood level.

What it opens up. Diseases of the cell's internal recycling compartments, and a common reason a drug accumulates in lung, liver, and eye tissue far beyond what the blood level suggests.

SETS HOW LONG IT LASTS

Trifluoromethyl

What it does. Blocks metabolism hard and makes the molecule substantially greasier and more membrane-permeable at the same time.

What it opens up. Long half-life plus good tissue and brain penetration — a common signature in drugs designed to be taken once daily.

02

Where it can get to

Predicted from molecular weight, lipophilicity, polar surface area and hydrogen-bond donor count. A drug can only act where it distributes, so this constrains which conditions are addressable before any biology is considered. derived

Easily
Systemic circulation
Absorbed from the gut and distributed in plasma.
Easily
Central nervous system
Crosses the blood–brain barrier.
No
Intestinal lumen only
Poorly absorbed. Acts locally in the gut with minimal systemic exposure.
Easily
Skin
Crosses the stratum corneum. Viable as a topical.
Barely
Urinary tract
Cleared unchanged in urine. Local concentration exceeds plasma.
03

What it binds — and whether we can reach it · 1 of 6 reachable

Binding affinity is only meaningful against the plasma concentration reached at the approved dose. A target requiring higher concentrations cannot be engaged in a patient, whatever the in vitro potency. Most repurposing hypotheses fail at this step, and it is rarely checked before a trial is proposed. measured

Values are pAct — the negative logarithm of the molar concentration at which the drug half-occupies the target. Each whole step is a tenfold difference in potency: 9.0 = 1 nanomolar, 6.0 = 1 micromolar, 5.0 = 10 micromolar. Oral drugs typically reach 0.1–10 micromolar in plasma, so roughly 6.0 is the threshold below which a target cannot be reached at a tolerated dose. Figures come from DrugCentral’s curated binding data.
ADORA2A
GPCR ·
6.91
Just reachable
ADORA1
GPCR ·
5.91
Out of reach
GLRA1
Ion channel ·
5.6
Out of reach
KCNH2
Ion channel ·
5.25
Out of reach
ABCB1
Transporter ·
Never measured
HBA1
Secreted ·
Never measured

This molecule builds up inside cells far above blood levels. Local concentration therefore exceeds plasma, so targets that look unreachable on a plasma reading may still be engaged. assumed

04

New uses, and who is already trying them

One card per candidate indication: the reasoning link by link, the evidence tier that governs how strongly it can be stated, and any registered trials.

5 of the 63 conditions linked to this drug’s targets have been checked against trial records so far. The rest are not ruled out — they are unchecked.

Not yet used for these — 5

Romano-Ward syndrome

Wide open

It acts on a target linked to this disease; untested, and the direction of effect is unverified.

The condition
No description on file.
KCNH2 · potassium voltage-gated channel subfamily H member 2
Pore-forming (alpha) subunit of voltage-gated inwardly rectifying potassium channel (PubMed:10219239, PubMed:10753933, PubMed:10790218, PubMed:10837251, PubMed:11997281, PubMed:12063277, PubMed:18559421, PubMed:22314138, PubMed:22359612, PubMed:26363003, PubMed:27916661, PubMed:9230439, PubMed:9351446, PubMed:9765245). Channel properties are modulated by cAMP and subunit assembly (PubMed:10837251). Characterized by unusual gating kinetics by producing relatively small outward currents during membrane depolarization
Nobody has tried this
No registered trial of this drug in this condition.
What would kill it. A null trial, or pharmacokinetic data showing the drug does not reach KCNH2 in the relevant tissue at tolerated doses.

hereditary hyperekplexia

Wide open

It acts on a target linked to this disease; untested, and the direction of effect is unverified.

The condition
Hereditary hyperekplexia is a hereditary neurological disorder characterized by excessive startle responses.
GLRA1
No function on file.
Nobody has tried this
No registered trial of this drug in this condition.
What would kill it. A null trial, or pharmacokinetic data showing the drug does not reach GLRA1 in the relevant tissue at tolerated doses.

Familial short QT syndrome

Wide open

It acts on a target linked to this disease; untested, and the direction of effect is unverified.

The condition
No description on file.
KCNH2 · potassium voltage-gated channel subfamily H member 2
Pore-forming (alpha) subunit of voltage-gated inwardly rectifying potassium channel (PubMed:10219239, PubMed:10753933, PubMed:10790218, PubMed:10837251, PubMed:11997281, PubMed:12063277, PubMed:18559421, PubMed:22314138, PubMed:22359612, PubMed:26363003, PubMed:27916661, PubMed:9230439, PubMed:9351446, PubMed:9765245). Channel properties are modulated by cAMP and subunit assembly (PubMed:10837251). Characterized by unusual gating kinetics by producing relatively small outward currents during membrane depolarization
Nobody has tried this
No registered trial of this drug in this condition.
What would kill it. A null trial, or pharmacokinetic data showing the drug does not reach KCNH2 in the relevant tissue at tolerated doses.

atrial fibrillation

Wide open

It acts on a target linked to this disease; untested, and the direction of effect is unverified.

The condition
A disorder characterized by an electrocardiographic finding of a supraventricular arrhythmia characterized by the replacement of consistent P waves by rapid oscillations or fibrillatory waves that vary in size, shape and timing and are accompanied by an irregular ventricular response. (CDISC)
KCNH2 · potassium voltage-gated channel subfamily H member 2
Pore-forming (alpha) subunit of voltage-gated inwardly rectifying potassium channel (PubMed:10219239, PubMed:10753933, PubMed:10790218, PubMed:10837251, PubMed:11997281, PubMed:12063277, PubMed:18559421, PubMed:22314138, PubMed:22359612, PubMed:26363003, PubMed:27916661, PubMed:9230439, PubMed:9351446, PubMed:9765245). Channel properties are modulated by cAMP and subunit assembly (PubMed:10837251). Characterized by unusual gating kinetics by producing relatively small outward currents during membrane depolarization
Nobody has tried this
No registered trial of this drug in this condition.
What would kill it. A null trial, or pharmacokinetic data showing the drug does not reach KCNH2 in the relevant tissue at tolerated doses.

cardiac arrhythmia

Wide open

It acts on a target linked to this disease; untested, and the direction of effect is unverified.

The condition
Any disturbances of the normal rhythmic beating of the heart or MYOCARDIAL CONTRACTION. Cardiac arrhythmias can be classified by the abnormalities in HEART RATE, disorders of electrical impulse generation, or impulse conduction.
KCNH2 · potassium voltage-gated channel subfamily H member 2
Pore-forming (alpha) subunit of voltage-gated inwardly rectifying potassium channel (PubMed:10219239, PubMed:10753933, PubMed:10790218, PubMed:10837251, PubMed:11997281, PubMed:12063277, PubMed:18559421, PubMed:22314138, PubMed:22359612, PubMed:26363003, PubMed:27916661, PubMed:9230439, PubMed:9351446, PubMed:9765245). Channel properties are modulated by cAMP and subunit assembly (PubMed:10837251). Characterized by unusual gating kinetics by producing relatively small outward currents during membrane depolarization
Nobody has tried this
No registered trial of this drug in this condition.
What would kill it. A null trial, or pharmacokinetic data showing the drug does not reach KCNH2 in the relevant tissue at tolerated doses.
05

Why nobody will fund it

2 companies make this across 2 approved products. With that many manufacturers the price has fallen to production cost. A company funding a trial could not recover it — competitors could market the same molecule for the new indication immediately, without contributing.

How abandoned it is9 / 100
0 to 100, calculated from manufacturer count, remaining patent or exclusivity, and whether any reformulation route to exclusivity is still open. 100 means no route to commercial return exists. The weights behind it are unsourced.
THE ONE WAY A COMPANY COULD STILL OWN IT
topicalinjectableinhaledmodified-release

A new route or dosage form qualifies for a 505(b)(2) application, which carries three years of exclusivity for that formulation. It is the only remaining route to exclusivity on a generic molecule.

06

What it would cost to find out

Derived, not quoted. Events needed is 4(zα+zβ)²/ln(HR)²; enrolment is that divided by the event rate and follow-up. The 1/ln(HR)² term dominates: halving the detectable effect size roughly quadruples enrolment. derived

0.75
Lower = bigger effect = smaller trial
8.0%
2 yr
$32K
Unsourced placeholder
379
Events needed
3K
Patients
$93M
Trial cost
assumed
$12.26
Per person reached
assumed

Cost per person reached is the relevant metric for a non-commercial funder, since there is no revenue to set against the outlay.

07

Ask for ideas nobody has listed

Reasons from the functional groups and distribution above, excluding conditions already listed. Output is hypotheses for falsification, not findings. Not medical advice.

08

Who might pay for the trial

Trials of off-patent drugs are rarely funded by venture capital or pharma. They are paid for by government grants and disease foundations. Here is who has funded work on this molecule before, what federal mechanisms are open now, and which foundations fund trials in the disease areas it touches. measured

Federal grants that name this medicine
143 grants on NIH RePORTER
5R37AI050234-24(NIAID · National Institute of Allergy & Infectious Diseases)Active
$547K (2026)
Defining the Role of PfCRT and PfMDR1 as Pleiotropic Mediators of Plasmodium falciparum Multidrug Resistance
PI: Fidock, David A · Columbia University Health Sciences, New York, NY · through 2028-01
5F32EY036283-03(NEI · National Eye Institute)Active
$84K (2026)
Structural basis of selective inhibition toward gap junction channels involved in vision.
PI: Souza, Samson · Oregon Health & Science University, Portland, OR · through 2027-06
3U19AI129392-11S1(NIAID · National Institute of Allergy & Infectious Diseases)Active
$192K (2026)
Understanding and Targeting the Barriers to Effective Malaria Control and Elimination in the Asia-Pacific Region
PI: Mueller, Ivo J · Walter And Eliza Hall Inst Medical Res, Parkville · through 2029-03
Open federal programmes that would fund this work

Open notices with an explicit mandate to fund work on approved or off-patent molecules.

RFA-CA-25-033National Institutes of HealthForecast — not open yet
Glioblastoma Therapeutics Network (GTN; U19 Clinical Trial Required)
RFA-FD-25-020Food and Drug Administrationcloses 05/16/2028
Reissue of RFA-FD-23-001- Clinical Studies of Orphan Products Addressing Unmet
FOR-FD-25-020Food and Drug AdministrationForecast — not open yet
Clinical Studies of Orphan Products Addressing Unmet Needs of Rare Diseases (R
FOR-FD-25-001Food and Drug AdministrationForecast — not open yet
Clinical Trials Addressing Unmet Needs of Rare Neurodegenerative Diseases (R01
RFA-TR-25-002National Institutes of Healthcloses 07/02/2027
Preclinical Proof of Concept Studies for Rare Diseases (R21 Clinical Trial Not
PAR-25-374National Institutes of Healthcloses 05/07/2028
Translational Bioinformatics and Experimental Approaches to Advance Drug Repos
HT942526PRCRPCTADefense Health Agency Contracting Activity -closes 10/05/2026
DoW Peer Reviewed Cancer, Clinical Trial Award
PAR-26-049National Institutes of HealthForecast — not open yet
Establishing Pediatric CNS Pharmacodynamic Measures as Tools to Enable Psychia
Showing 8 of 990 currently open under this category on Grants.gov, matched to the disease areas this drug touches. derived Browse all 990 on Grants.gov ↗
Funders beyond the federal system

Grants.gov lists US federal money. Many off-patent drug trials are supported by disease foundations and nonprofits. These are matched to the body systems this drug touches. assumed

Matched by disease area, not by molecule — a foundation appearing here funds work in a field this drug touches.
09

Who manufactures it

Companies holding an approved abbreviated application for this molecule in the United States, from the FDA Orange Book. Supply already exists at scale, so a trial would not need a manufacturing programme — but any of these could also be a partner, or an objector.

Barr Laboratories IncChartwell Rx Sciences Llc
2
Manufacturers
companies with their own approval
2
Approved products
distinct strengths and forms
1
Routes
oral
2002
Oldest product still sold
approval year of the earliest product still on the market

Nothing on this page is medical advice. Candidate uses are unproven hypotheses derived from public data; established uses are listed for verification only. Figures carry their provenance inline — anything marked assumed or derived is not a measurement.

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