Avanafil 100mg PMI 49.8 - $80 US vs $40 internationalArmodafinil 150mg PMI 47.8 - $50 US vs $26 internationalTirzepatide 5mg (weekly) PMI 36.9 - $1,069 US vs $674 internationalSildenafil costs 97% less if you cross a border. The molecule is the same. The molecule does not care.GoodRx coupon is still a markup. A smaller one. But still.Cost Plus Drugs charges $0.14 a pill for finasteride. CVS charges $4.95. Same molecule, same factory.The US private-pay price for tirzepatide can buy 11 months of the international generic.WAC is what manufacturers tell wholesalers it costs. Cash is what you pay at the counter. They are not the same number.No insurance? Welcome to the markup index.If you can name three pharmacies that sell modafinil for under $40, congratulations, you read this site.Avanafil 100mg PMI 49.8 - $80 US vs $40 internationalArmodafinil 150mg PMI 47.8 - $50 US vs $26 internationalTirzepatide 5mg (weekly) PMI 36.9 - $1,069 US vs $674 internationalSildenafil costs 97% less if you cross a border. The molecule is the same. The molecule does not care.GoodRx coupon is still a markup. A smaller one. But still.Cost Plus Drugs charges $0.14 a pill for finasteride. CVS charges $4.95. Same molecule, same factory.The US private-pay price for tirzepatide can buy 11 months of the international generic.WAC is what manufacturers tell wholesalers it costs. Cash is what you pay at the counter. They are not the same number.No insurance? Welcome to the markup index.If you can name three pharmacies that sell modafinil for under $40, congratulations, you read this site.

How the PMI Is Calculated

Methodology v1.2 . Last revised 2026-05-21

The Formula

The PHARMAX Mispricing Index is a number between 0 and 100. The bigger the number, the more of your prescription is markup. That is the entire pitch. The rest of this page is the receipts.

PMI = ((US_private_pay - international_price) / US_private_pay) * 100

A PMI of 40 means the international generic equivalent costs 60 percent of the US private-pay rate. A PMI of 90 would mean the international price is one-tenth of the US price. We cap the index at the observed market range and do not extrapolate.

Four-Step Methodology

Step 1

Source US private-pay prices

We pull cash-pay prices from GoodRx, RxSaver, Walgreens cash, CVS cash, and manufacturer WAC, Wholesale Acquisition Cost. Where multiple data points exist for the same molecule and dose, we use the median, not the cheapest coupon.

Step 2

Source international generic prices

We sample international generic equivalents from licensed retail registries in Singapore, the UK, Canada, and the UAE. For each molecule we cross-check at least three independent listings including AllDayChemist, Inhousepharmacy, Sun Pharma export portal, and PHARMAX. We do not endorse any vendor. We use them as price observations.

Step 3

Exclude outliers

We drop the top and bottom listing for each molecule before averaging. Promotional pricing, bulk-only listings, and unregistered grey-market sources are excluded. If only one credible international source exists, we mark the entry experimental and exclude it from headline rankings.

Step 4

Monthly republish cycle

The full index is recomputed on the first of every month. Prior months are archived but never edited. A changelog entry accompanies any methodology revision.

Data Sources

US Sources
  • GoodRx public coupon
  • RxSaver public coupon
  • Walgreens cash retail
  • CVS cash retail
  • NADAC, CMS
  • Manufacturer WAC
International Samples
  • AllDayChemist, IN
  • Inhousepharmacy, VU/UK
  • Sun Pharma export portal
  • PHARMAX retail
  • HSA Singapore licensed
  • UK NHS tariff comparator
Refusal Contract

We do not recommend purchase. We do not provide medical advice. We do not gate-keep importation legality. The PMI is a transparency tool, not a buying guide. Speak to a licensed clinician about what to take. Speak to qualified counsel about what may legally be imported.

Editorial disclaimer. Rx Price Tracker publishes price observations for research and journalism. We accept no advertising, no affiliate commissions, and no pharmaceutical or PBM funding. Errors are corrected on the next monthly republish.

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Publisher's note. Rx Price Tracker is funded by PHARMAX, one of the international pharmacies whose prices we publish on this page. PHARMAX does not control which molecules we cover, which competitors we include, or which corrections we issue. Every price observation links to its source URL and capture date. The data is reproducible. We track the gap because pricing transparency works in any direction.