Phentolamine: uses, dosing, side effects & brands
Phentolamine is an alpha-adrenergic blocker sold in the U.S. under 3 brand and generic names, for extravasation of diagnostic and therapeutic materials, malignant hypertension and necrosis. Below: what the FDA label says, every product that contains it, what the pills look like, and its recall record.
Key facts
- Drug class
- Alpha-Adrenergic Blocker
- Treats (across its forms)
- Extravasation of Diagnostic and Therapeutic Materials, Malignant Hypertension and Necrosis
- Available as
- Injectable · Drops
- Sold as
- 3 products — Regitine, Oraverse and Ryzumvi
- Prescription?
- Prescription only
- Generic available?
- Not in our catalog
How Oraverse is dosed
From the FDA label for Oraverse (application NDA022159). Other phentolamine products — different forms, different strengths — are dosed differently. Follow the label for the one you were prescribed.
Amount of Local Anesthetic Administered Dose of OraVerse 1 / 4 Cartridge 1 / 4 Cartridge (0.1 mg) ½ Cartridge ½ Cartridge (0.2 mg) 1 Cartridge 1 Cartridge (0.4 mg) 2 Cartridges 2 Cartridges (0.8 mg) OraVerse is administered using the same location(s) and same technique(s) (infiltration or block injection) used for the administration of local anesthetic. ( 2.1 ) 2.1 General Dosing information The recommended dose of OraVerse is based on the number of cartridges of local anesthetic with vasoconstrictor administered: Amount of Local Anesthetic Administered Dose of OraVerse [mg] Dose of OraVerse [Cartridge(s)] 1 / 4 Cartridge 0.1 1 / 4 ½ Cartridge 0.2 ½ 1 Cartridge 0.4 1 2 Cartridges 0.8 2 OraVerse should be administered following the dental procedure using the same location(s) and technique(s) (infiltration or block injection) employed for the administration of the local anesthetic. Chemically disinfect the carpule cap by wiping with either isopropyl alcohol (91%) or ethyl alcohol (70%). Many commercially available brands of isopropyl (rubbing) alcohol, as well as solutions of ethyl alcohol not of U.S.P. grade, contain denaturants that are injurious to rubber and therefore are not to be used. Inspect carpules visually prior to administration and do not use if particulate matter, discoloration, cracks in the glass, protruding plungers or other defects are observed. Note: Do not…
Everything below is the FDA label for Oraverse (injectable). Phentolamine is also sold as drops, and those are different medicines to take — follow the label for the one you were prescribed.
Oraverse side effects
In clinical trials, the most common adverse reaction with OraVerse that was greater than the control group was injection site pain. The most common adverse reaction with OraVerse (incidence ≥5% and > control) is injection-site pain. ( 6 ) To report SUSPECTED ADVERSE REACTIONS, contact Septodont at 1-888-888-1441 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch . 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. Dental patients were administered a dose of either 0.2, 0.4 or 0.8mg of OraVerse. The majority of adverse reactions were mild and resolved within 48 hours. There were no serious adverse reactions and no discontinuations due to adverse reactions. Table 1 lists adverse reactions where the frequency was greater than or equal to 3% in any OraVerse dose group and was equal to or exceeded that of the control group. Table 1: Adverse Reactions with Frequency Greater Than or Equal to 3% and Equal to or Exceeding Control Adverse Event OraVerse Control 0.2 mg (N = 83) 0.4 mg (N = 284) 0.8 mg (N = 51) Total (N = 418) Total (N = 359) N (%) N (%) N (%) N (%) N (%) Patients with AEs 15 (18) 82 (29) 20 (39) 117 (28) 96 (27) Tachycardia 0 (0) 17…
Who shouldn’t take Oraverse
OraVerse is contraindicated in patients with: Hypersensitivity to the active substance or to any ingredients in the formulation OraVerse is contraindicated in patients with: Hypersensitivity to the active substance or to any ingredients in the formulation. ( 4 )
Oraverse drug interactions
There are no known drug interactions with OraVerse. 7.1 Lidocaine and Epinephrine When OraVerse was administered as an intraoral submucosal injection 30 minutes after injection of a local anesthetic, 2% lidocaine HCl with 1:100,000 epinephrine, the lidocaine concentration increased immediately after OraVerse intraoral injection. Lidocaine AUC and Cmax values were not affected by administration of OraVerse. OraVerse administration did not affect the PK of epinephrine.
Every phentolamine product we track (3)
Same active ingredient — different manufacturer, form, price and FDA recall record. That last one is what our independent score measures.
| # | Drug | Rating | Type | Form | Generic? | Pharmacy pays | |
|---|---|---|---|---|---|---|---|
| 1 | 70/100 | Prescription | Injectable | No data | — | View → | |
| 2 | Not yet rated | Prescription | Injectable | No data | — | View → | |
| 3 | Not yet rated | Prescription | Drops | No data | — | View → |
How long phentolamine keeps
The date on a sealed pack is not the only one: some phentolamine labels start a second clock once the product is opened or mixed, as short as 35 days.
Does phentolamine expire? The in-use limits and storage rules from its labelsWhat people report to the FDA about phentolamine
The FDA Adverse Event Reporting System (FAERS) collects reports from patients and clinicians. It holds 89 reports naming phentolamine, and the FDA flagged 90% of those reports as serious. The effects reported most often — leaving out reports about overdose, misuse or the condition being treated, which dominate the raw list for common medicines:
- blood urea increased14 reports
- anaemia13 reports
- blood glucose increased13 reports
- neutrophil count increased13 reports
- diarrhoea12 reports
- lymphocyte count decreased12 reports
- hypertension11 reports
- abdominal distension9 reports
Read these as a signal, not a rate. A report does not mean phentolamine caused the effect — anyone can file one, and many describe people taking several medicines for several conditions. Crucially there is no denominator: FAERS does not record how many people took the drug, so these counts cannot be turned into “X% of patients” — a bigger number often just means a more widely used or more talked-about drug. Duplicates exist, and publicity drives reporting. For what is actually established, read the FDA label section above.
Source: openFDA drug/event (FAERS), retrieved July 27, 2026.
Related calculators
Frequently asked questions
What is Oraverse?
Oraverse (Phentolamine Mesylate) is an alpha-adrenergic blocker used to treat Extravasation of Diagnostic and Therapeutic Materials, Malignant Hypertension, Necrosis.
What kind of drug is phentolamine?
The FDA classifies phentolamine as an alpha-adrenergic blocker. Alpha-adrenergic blockers block the alpha-1 receptors that adrenaline-like signals use to tighten muscle in blood vessels and the prostate. This relaxes those muscles, lowering blood pressure and easing urine flow in men with an enlarged prostate. If you are checking whether it is safe to combine with something else, the class is what matters — two drugs from the same class usually should not be stacked.
Can you take phentolamine with other medicines?
It depends on the medicine. We check it against the FDA labels rather than guessing: our interaction checker searches each drug's own label for the other and quotes what it says, naming the section it came from. Run phentolamine against whatever else you take — and remember that a label not naming a drug is not the same as that combination being safe.
What brand names is phentolamine sold under?
We track 3 phentolamine-containing products in the U.S.: Regitine, Oraverse and Ryzumvi. They are the same active ingredient; they differ in form, manufacturer, price and FDA recall record.
What forms does phentolamine come in?
Across the brands we track, phentolamine is currently marketed as injectable and drops, per the FDA's National Drug Code Directory. Each form is dosed differently — follow the label for the exact product you were prescribed.
Is there a generic phentolamine?
We do not currently list a generic-labelled phentolamine product. That does not always mean none exists — it means none appears under a generic name in the FDA data we track. Ask your pharmacist.
Cite this page
- APA
- pharmaranks. (2026, July 24). Phentolamine: uses, dosing, side effects & brands. https://pharmaranks.com/drugs/phentolamine
- MLA
- “Phentolamine: uses, dosing, side effects & brands.” pharmaranks, 24 July 2026, https://pharmaranks.com/drugs/phentolamine.
We summarise public FDA and NIH sources — for a clinical claim, cite the primary source we link to as well.
Sources: FDA openFDA drug label, National Drug Code Directory, and Enforcement (recall) database. This page reproduces public FDA data and is not medical advice. Dosing is set by your prescriber.
Read the full FDA label for phentolamine on DailyMed (NIH) ↗.