Pharmacologic class (EPC) · 13 drug pages

Central alpha-2 adrenergic agonist: adverse event reports filed with FDA

31,745 reports list a drug in this class as a suspect or interacting product, 2004–2026.

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.

31,745
reports across the class: 0.2% of all reports; 2,263
reports, 12 months to June 2026: 2,218 in the 12 months before; 75.5%
marked serious by the reporter: 57.4% across all reports; 13
drugs with a page: brand and generic names counted separately

Central alpha-2 adrenergic agonist is a pharmacologic class (an FDA Established Pharmacologic Class) with 13 drug pages on this site. Together those drugs are listed as a suspect or interacting product in 31,745 adverse event reports received by FDA, 0.2% of the database, from January 2004 to June 2026.

2,263 reports arrived in the 12 months to June 2026, close to the 2,218 of the 12 months before. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases. 75.5% of the class's reports are marked serious, 16.2% record death among the outcomes and 30.4% record hospitalisation, as reported.

Across the class the reactions recorded most often are drug ineffective (11.3%), off label use (8%) and completed suicide (6.9%). The class median share shown beside each term is the middle value across the member drugs; it is the comparison used on every drug page in this class.

The members table is ordered by report count for navigation only. 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."

Drugs in the class

Drug	Name type	Reports	Latest 12 months	Marked serious	Top term recorded
Clonidine	generic	11,712	713	79.2%	Drug ineffective
Tizanidine	generic	4,259	376	69.8%	Completed suicide
Methyldopa	generic	2,659	138	95.8%	Foetal exposure during pregnancy
IntunivGuanfacine	brand	2,180	48	75.8%	Somnolence
Clonidine hydrochloride	generic	1,842	260	77.8%	Hypertension
Dexmedetomidine	generic	1,653	160	93.2%	Drug ineffective
Guanfacine	generic	1,445	214	61.7%	Drug ineffective
Dexmedetomidine hydrochloride	generic	1,436	134	98%	Bradycardia
ZanaflexTizanidine hydrochloride	brand	1,166	10	54.5%	Drug hypersensitivity
Tizanidine hydrochloride	generic	1,051	104	80.3%	Somnolence
Clonidine transdermal system	generic	873	86	15%	Application site pruritus
Catapres-TTS-1Clonidine transdermal system	brand	871	0	18%	Application site pruritus
PrecedexDexmedetomidine hydrochloride	brand	598	20	78.1%	Bradycardia

Ordered by report count for navigation only. 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."

Reports by month, five years

FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases.

Reactions recorded across the class

share of class reports recording the termmedian drug in the class

Drug ineffectivethe medicine did not work as expected11.3%3,575
Off label useused for a purpose or in a way not on the label8%2,524
Completed suicidedeath by suicide6.9%2,199
Hypertensionhigh blood pressure6.1%1,930
Hypotensionlow blood pressure5.7%1,812
Headachehead pain5.3%1,695
Somnolencedrowsiness5.2%1,662
Toxicity to various agentspoisoning or toxic effect of one or more substances5.1%1,631
Fatiguetiredness5.1%1,615
Painpain, site not specified5.1%1,612
Bradycardiaslow heart rate4.3%1,372
Overdosea dose above the recommended amount4.3%1,356
Exposure during pregnancythe medicine was taken during pregnancy4%1,267
Foetal exposure during pregnancythe unborn baby was exposed to the medicine3.8%1,196
Dizzinesslight-headedness or unsteadiness3.7%1,159
Nauseafeeling sick3.4%1,074
Hypersensitivityan allergic-type reaction3.4%1,072
Product use issuea problem in how the product was used3.2%1,023
Drug interactionan interaction between medicines3.2%1,013
Drug hypersensitivityan allergic-type reaction to a medicine3.1%991
Hyperhidrosisexcessive sweating3.1%987
Hepatic enzyme increasedraised liver enzymes2.9%926
Blood pressure increaseda raised blood pressure reading2.9%905
Premature babya baby born early2.7%866
Pyrexiafever2.7%850

Solid bar: share of all class reports. Hollow bar: the median share across the 13 member drugs, the reference used on each member's page. One report can record several terms.

Outcomes, patients and reporters

Outcomes recorded

Death16.2%5,127

Life-threatening7.3%2,333

Hospitalisation (initial or prolonged)30.4%9,637

Disability1.5%488

Congenital anomaly1.5%486

Other serious51.5%16,346

Not serious24.5%7,790

Patient age

Under 22.1%679

2 to 116.9%2,190

12 to 174.3%1,350

18 to 4416.7%5,312

45 to 6421%6,665

65 to 747.6%2,402

75 and over5.7%1,817

Age not given35.7%11,330

Who reported

Physician26.5%8,408

Pharmacist7.9%2,522

Other health professional34.1%10,814

Lawyer0.2%67

Consumer or non-health professional27.5%8,726

Not given3.8%1,208

Grey bar: all 20,646,523 reports in the database. Outcome flags are as the reporter set them and are not verified by FDA.

Questions about Central alpha-2 adrenergic agonist reports

Which drugs are in the Central alpha-2 adrenergic agonist class on this site?

Clonidine, Tizanidine, Methyldopa, Intuniv, Clonidine hydrochloride and Dexmedetomidine and 7 more. Class membership comes from the pharmacologic class (EPC) on the drug's FDA label.

How many reports does the class have?

31,745 reports through June 2026, 2,263 of them in the latest 12 months. A report listing two drugs of the class counts once for each.

What reactions are recorded most often?

drug ineffective (11.3%), off label use (8%), completed suicide (6.9%), hypertension (6.1%) and hypotension (5.7%).

Can the members table be used to rank the drugs?

No. 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." Drugs differ in how many people take them, in the conditions they treat, in time on the market and in how diligently reports are collected.

How do I report an adverse event?

Through FDA MedWatch (Form FDA 3500, or 1-800-FDA-1088) or to the manufacturer. See the guide on how to report.

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. A class is the Established Pharmacologic Class most often attached to a drug's reports by openFDA's label harmonisation, or from the NDC Directory where reports carry none. 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.