| Cover | Mar. 29, 2023 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Mar. 29, 2023 |
| Entity File Number | 001-41475 |
| Entity Registrant Name | PaxMedica, Inc. |
| Entity Central Index Key | 0001811623 |
| Entity Tax Identification Number | 85-0870387 |
| Entity Incorporation, State or Country Code | DE |
| Entity Address, Address Line One | 303 South Broadway |
| Entity Address, Address Line Two | Suite 125 |
| Entity Address, City or Town | Tarrytown |
| Entity Address, State or Province | NY |
| Entity Address, Postal Zip Code | 10591 |
| City Area Code | 914 |
| Local Phone Number | 987-2876 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, par value $0.0001 per share |
| Trading Symbol | PXMD |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | true |
| Elected Not To Use the Extended Transition Period | false |
