MedDRA preferred term

Application site vesicles: adverse event reports recording this term

6,425 reports to FDA record it, 2004–2026; 0% of the database.

Read first · FDA's statement on these data

Adverse event reports submitted to FDA do not undergo extensive validation or verification. Therefore, a causal relationship cannot be established between product and reactions listed in a report. While a suspected relationship may exist, it is not medically validated and should not be the sole source of information for clinical decision making or other assumptions about the safety or efficacy of a product. Additionally, it is important to remember that adverse event reports represent a small percentage of total usage numbers of a product. Common products may have a higher number of adverse events due to the higher total number of people using the product. openFDA, FDA

FDA adds: "There is no certainty that the reported event (adverse event or medication error) was actually due to the product. FDA does not require that a causal relationship between a product and event be proven, and reports do not always contain enough detail to properly evaluate an event." The information in these reports "cannot be used to estimate the incidence of these events."

Do not rely on openFDA to make decisions regarding medical care. While we make every effort to ensure that data is accurate, you should assume all results are unvalidated.

Not medical advice. This site counts what was reported to FDA. Questions about a medicine or device belong with a pharmacist or clinician.

6,425
reports recording the term: 0% of all reports; 153
reports, 12 months to June 2026: 136 in the 12 months before; 25.6%
marked serious by the reporter: 57.4% across all reports; 0.2%
record death among outcomes, as reported: 9.1% across all reports

"Application site vesicles" is a MedDRA preferred term recorded in 6,425 adverse event reports received by FDA, 0% of the database, from February 2004 to June 2026. The term is chosen by whoever codes the report to match what the reporter described.

153 reports recorded it in the 12 months to June 2026, up 13% from 136 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, 25.6% are marked serious, 0.2% include death among the outcomes and 3.4% include hospitalisation, as reported.

The drugs listed most often as suspect products in those reports are Picato, Butrans and Zecuity. 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
Picato	—	1,371	28.5%
Butrans	Partial opioid agonist	962	1.6%
Zecuity	—	259	8.9%
Nicoderm Cq	Cholinergic nicotinic agonist	248	1.6%
Fentanyl Transdermal System	—	141	1.1%
Estradiol Transdermal System	Estrogen	113	1.9%
Minoxidil	Arteriolar vasodilator	110	0.4%
Picato Gel	—	100	29%
Daytrana	Central nervous system stimulant	97	0.7%
Abreva	Non-Standardized chemical allergen	86	0.6%
Fentanyl	Opioid agonist	79	0.1%
Neupro	Nonergot dopamine agonist	76	1.2%
Estradiol	Estrogen	73	0.5%
Valchlor	Alkylating drug	71	3.4%
Duragesic-100	—	69	0.7%
Diclofenac sodium	Nonsteroidal anti-inflammatory drug	65	0.1%
Chloraprep with Tint	—	52	4%
Qutenza	—	52	3.1%
Buprenorphine	Partial opioid agonist	48	0.2%
Catapres-TTS-1	Central alpha-2 adrenergic agonist	39	4.5%
Jublia	Azole antifungal	38	3%
Nicotine	Cholinergic nicotinic agonist	38	0.4%
CombiPatch (estradiol/norethindrone acetate transdermal system)	Estrogen	37	1%
Oxytrol for Women	Cholinergic muscarinic antagonist	37	0.6%
Clonidine transdermal system	Central alpha-2 adrenergic agonist	36	4.1%

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% 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
Partial opioid agonist	1,026	1.1%	0%
Cholinergic nicotinic agonist	364	0.7%	0.5%
Estrogen	304	0.2%	0%
Arteriolar vasodilator	138	0.3%	0.1%
Central alpha-2 adrenergic agonist	106	0.3%	0%
Central nervous system stimulant	97	0.1%	0%
Opioid agonist	95	0%	0%
Nonsteroidal anti-inflammatory drug	93	0%	0%
Non-Standardized chemical allergen	86	0.5%	0%
Nonergot dopamine agonist	79	0.4%	0%

Classes ordered by count. Class shares follow the class's overall report volume as much as anything else.

Patients in these reports

Patient age

Under 20.4%28

2 to 111.6%106

12 to 170.6%37

18 to 4411.6%746

45 to 6426.8%1,719

65 to 749.2%593

75 and over4.6%295

Age not given45.2%2,901

Patient sex

Female68.1%4,378

Male25.6%1,645

Not given6.3%402

Grey bar: all 20,646,523 reports in the database. 92.7% of these reports give the United States as the country.

Questions about "Application site vesicles"

What does "Application site vesicles" 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 application site vesicles?

6,425 reports through June 2026 (0% of all reports), 153 of them in the latest 12 months.

Which drugs appear most often in these reports?

Picato (1,371), Butrans (962), Zecuity (259), Nicoderm Cq (248) and Fentanyl Transdermal System (141). 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.