MedDRA preferred term
Drug resistance: adverse event reports recording this term
25,326 reports to FDA record it, 2004–2026; 0.1% of the database.
- 25,326
- reports recording the term
- 0.1% of all reports
- 1,462
- reports, 12 months to June 2026
- 2,078 in the 12 months before
- 88.8%
- marked serious by the reporter
- 57.4% across all reports
- 11.8%
- record death among outcomes, as reported
- 9.1% across all reports
25,326 reports in FDA's adverse event database record the MedDRA term "Drug resistance": 0.1% of all reports received between January 2004 and June 2026. Coders pick the term that best matches the reporter's description.
1,462 reports recorded it in the 12 months to June 2026, down 30% from 2,078 in the 12 months before. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases. Of reports recording this term, 88.8% are marked serious, 11.8% include death among the outcomes and 19.7% include hospitalisation, as reported.
The drugs listed most often as suspect products in those reports are Lamivudine, Nevirapine and Imatinib. That order mostly follows how many reports each drug has overall; the table also gives the term's share within each drug's own reports. FDA states that "a causal relationship cannot be established between product and reactions listed in a report" and that for any given report "there is no certainty that a suspected drug caused the event."
Reports by month, five years
FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases.
Drugs listed as suspect products in these reports
| Drug | Class | Reports with this term | Share of the drug's own reports |
|---|---|---|---|
| Lamivudine | Hepatitis B virus nucleoside analog reverse transcriptase inhibitor | 1,766 | 9.8% |
| Nevirapine | Human immunodeficiency virus 1 Non-Nucleoside analog reverse transcriptase inhibitor | 1,025 | 12.9% |
| Imatinib | Kinase inhibitor | 944 | 6.8% |
| Prednisone | Corticosteroid | 873 | 0.5% |
| Levetiracetam | — | 800 | 1.5% |
| Osimertinib | Kinase inhibitor | 775 | 10.1% |
| Iressa | Kinase inhibitor | 760 | 11.8% |
| Methotrexate | Folate analog metabolic inhibitor | 726 | 0.4% |
| Cyclophosphamide | Alkylating drug | 713 | 0.5% |
| Efavirenz | Human immunodeficiency virus 1 Non-Nucleoside analog reverse transcriptase inhibitor | 713 | 7.8% |
| Rituximab | CD20-directed cytolytic antibody | 670 | 0.4% |
| Mycophenolate mofetil | Antimetabolite immunosuppressant | 653 | 0.8% |
| Zidovudine | Human immunodeficiency virus nucleoside analog reverse transcriptase inhibitor | 637 | 7.5% |
| Tacrolimus | Calcineurin inhibitor immunosuppressant | 634 | 0.7% |
| Prednisolone | Corticosteroid | 631 | 0.7% |
| Linezolid | Oxazolidinone antibacterial | 616 | 3.4% |
| Ganciclovir | Cytomegalovirus nucleoside analog DNA polymerase inhibitor | 590 | 12.5% |
| Meropenem | Penem antibacterial | 565 | 3.7% |
| Dasatinib | Kinase inhibitor | 506 | 6.2% |
| Ciprofloxacin | Fluoroquinolone antibacterial | 503 | 1.3% |
| Humira | — | 502 | 0.1% |
| Voriconazole | Azole antifungal | 495 | 3.7% |
| Ritonavir | Cytochrome P450 3A inhibitor | 494 | 4.3% |
| Carboplatin | Platinum-based drug | 493 | 0.5% |
| Valganciclovir | Cytomegalovirus nucleoside analog DNA polymerase inhibitor | 480 | 9.1% |
Drugs with a page on this site, ordered by the number of their reports recording this term. The last column is the term's share within that drug's own reports, against 0.1% across the whole database. FDA states that adverse event reports "represent a small percentage of total usage numbers of a product", that "common products may have a higher number of adverse events due to the higher total number of people using the product", and that the data "by themselves are not an indicator of the safety profile of the drug or biologic."
By pharmacologic class
| Class | Reports with this term | Share of class reports | Median drug in class |
|---|---|---|---|
| Kinase inhibitor | 6,259 | 0.7% | 0.1% |
| Hepatitis B virus nucleoside analog reverse transcriptase inhibitor | 3,279 | 4.5% | 2.3% |
| Corticosteroid | 2,756 | 0.3% | 0% |
| Human immunodeficiency virus 1 Non-Nucleoside analog reverse transcriptase inhibitor | 2,115 | 7.3% | 2% |
| Anti-epileptic agent | 1,816 | 0.7% | 0.5% |
| Human immunodeficiency virus nucleoside analog reverse transcriptase inhibitor | 1,656 | 2% | 1.2% |
| Fluoroquinolone antibacterial | 1,320 | 1.5% | 1.3% |
| Atypical antipsychotic | 1,267 | 0.2% | 0% |
| Cytomegalovirus nucleoside analog DNA polymerase inhibitor | 1,207 | 8.6% | 9.1% |
| Alkylating drug | 1,206 | 0.5% | 0.2% |
Classes ordered by count. Class shares follow the class's overall report volume as much as anything else.
Patients in these reports
Patient age
Patient sex
Grey bar: all 20,646,523 reports in the database. 29.3% of these reports give the United States as the country.
Questions about "Drug resistance"
What does "Drug resistance" mean in an adverse event report?
It is a MedDRA preferred term, the dictionary FDA uses to code what a reporter described. The report's own description is not published by openFDA and is not shown here.
How many reports record drug resistance?
25,326 reports through June 2026 (0.1% of all reports), 1,462 of them in the latest 12 months.
Which drugs appear most often in these reports?
Lamivudine (1,766), Nevirapine (1,025), Imatinib (944), Prednisone (873) and Levetiracetam (800). Drugs with many reports overall lead almost every term's list. FDA states that adverse event reports "represent a small percentage of total usage numbers of a product", that "common products may have a higher number of adverse events due to the higher total number of people using the product", and that the data "by themselves are not an indicator of the safety profile of the drug or biologic."
Does a drug appearing here mean it was responsible for this reaction?
No. FDA states that "a causal relationship cannot be established between product and reactions listed in a report" and that for any given report "there is no certainty that a suspected drug caused the event."
I have this symptom. What should I do?
This site cannot assess anyone. A pharmacist or clinician can; for an emergency, call the local emergency number. Nothing on this page is medical advice.
Where this comes from. Counts are built from the openFDA Drug Adverse Event (FAERS) bulk export released 28 Sep 2026, which holds reports FDA received through 30 Jun 2026. Drug names are as reported, resolved to the brand or generic name on the FDA label where openFDA's harmonisation matched them; classes are the pharmacologic class (EPC) from the label and the National Drug Code Directory of 17 Sep 2026. Terms are pooled across spelling and capitalisation variants of one MedDRA preferred term. No report narrative, lot number, patient detail or reporter identity is published. See the methodology and sources; FDA's record is authoritative, and corrections are handled within five working days.
Drug data (FAERS) through 30 Jun 2026; device data (MAUDE) through 31 Aug 2026. Not medical advice.