Phentolamine 5mg/1ml solution for injection vials
Requires a prescription from a doctor or prescriber
Phentolamine is a reversible, non-selective alpha-adrenergic blocker that induces vasodilation.
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Safety monitoring data
Yellow Card reports
The MHRA Yellow Card scheme collects reports of suspected side effects from healthcare professionals and patients. View the Drug Analysis Profile (iDAP) for real-world adverse reaction data.
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Suspected adverse reactions reported for Phentolamine
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Data from the MHRA Yellow Card scheme. A reported reaction does not necessarily mean the medicine caused it. Contains public sector information licensed under the Open Government Licence v3.0.
EudraVigilance
The European Medicines Agency (EMA) collects suspected adverse reaction reports from across the EU/EEA through the EudraVigilance system. Search for safety data on this medicine.
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Suspected adverse reactions reported for Phentolamine
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EudraVigilance data is published by the European Medicines Agency (EMA). A suspected adverse reaction is not necessarily caused by the medicine.
1 branded products available
Therapeutically similar medicines
Similarity is based on WHO Anatomical Therapeutic Chemical (ATC) classification and on a factual NHS dm+d therapeutic-grouping code prefix. Source data: NHS dm+d via TRUD (OGL v3.0), WHO ATC/DDD Index.
Check stock at pharmacies and supply information
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Supply & safety information
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Pharmacy links redirect to the retailer's own search and do not represent real-time stock levels. Shortage and safety information sourced from MHRA drug safety updates (gov.uk, Crown Copyright under OGL v3.0).
Codes for healthcare professionals and prescribing systems
These codes are used by healthcare IT systems and prescribers to identify this medicine.
NHS UK identifiers
Browse tools
SNOMED CT and dm+d codes from NHS TRUD (Technology Reference data Update Distribution), licensed under the Open Government Licence v3.0. BNF code shown is the factual mapping value distributed by NHS Business Services Authority (NHSBSA) in the dm+d supplementary file under OGL v3.0; it is not affiliated with, nor licensed from, the publishers of the British National Formulary. ATC codes from the WHO Collaborating Centre for Drug Statistics Methodology (whocc.no).
Active and completed clinical studies from ClinicalTrials.gov
Source: ClinicalTrials.gov, a database of the U.S. National Library of Medicine (NLM), National Institutes of Health (NIH). Data accessed via ClinicalTrials.gov API v2. Trial information is provided for research purposes and does not constitute medical advice.
Academic studies and reviews for this medicine's active substance
Showing all 28 studies.
Reviews & meta-analyses: 3 · 1971–2026
Showing all 28 studies, sorted by most relevant.
H. de Wit, R. Wise
Canadian journal of psychology, 1977
- Reinforcement, Psychology
- Cocaine
- Phenoxybenzamine
S. Raja, R. Treede, K. Davis, et al.
Anesthesiology, 1991
- Phentolamine
- Prohibitins
- Bupivacaine
Richard R. Miller, L. Vismara, David O. Williams, et al.
Circulation Research, 1976
- Blood Pressure
- Cardiac Output
- Ferricyanides
Majid Pa, B. Sharma, S. Taylor
Lancet, 1971
- Adrenergic alpha-Antagonists
- Heart
- Heart Failure
G. Neil-Dwyer, P. Walter, J. Cruickshank, et al.
British Medical Journal, 1978
- Clinical Trials as Topic
- Electrocardiography
- Myocardium
S. Arnér
Pain, 1991
- Phentolamine
- Guanethidine
- Injections, Intravenous
P. Proks, F. Ashcroft
Proceedings of the National Academy of Sciences of the United States of America, 1997
- Cell Line
- Imidazoles
- Membrane Potentials
S. Levine, S. Althof, L. Turner, et al.
The Journal of urology, 1989
- Erectile Dysfunction
- Injections
- Liver Function Tests
S. M. Kirpekar, M. Puig
British Journal of Pharmacology, 1971
- Cats
- Cocaine
- Electric Stimulation
I. Goldstein
International Journal of Impotence Research, 2000
- Adrenergic alpha-Antagonists
- Erectile Dysfunction
- Kinetics
Sources: aggregated from Europe PMC (EMBL-EBI), OpenAlex, Crossref, PubMed and other open scholarly databases. Retracted articles are excluded. Study information is provided for research purposes and does not constitute medical advice.
Pharmacology and chemical data from DrugBank
Key facts
Drug status
Approved
Major interactions
64 found
Half-life
19 minutes
Mechanism
Phentolamine is a reversible, competitive antagonist at alpha-1 and alpha-2 adrenergic receptors.
Food interactions
None known
Human targets
4 targets
Data: DrugBank · CC BY-NC 4.0
Pharmacokinetics at a glance
Absorption
10 to 20 minutes
Half-life
19 minutes
[L48420]…
Volume of distribution
[A261766]
Elimination
13%
[L48420]
Pharmacokinetic data: DrugBank · CC BY-NC 4.0
[L48420]
Submucosal injection of phentolamine is indicated for the reversal of soft-tissue anesthesia (e.g. anesthesia of the lip and tongue) and the associated functional deficits resulting from an intraoral submucosal injection of a local anesthetic containing a vasoconstrictor in patients three years old and older.
[L48415]
Phentolamine ophthalmic solution is used to treat pharmacologically-induced mydriasis produced by adrenergic agonists (e.g., phenylephrine) or parasympatholytic (e.g., tropicamide) agents.
[L48390]
Known interactions with other medications. Always consult a healthcare professional.
Showing 50 of 707 interactions
[L48410][L48420]
No deaths due to acute poisoning with phentolamine have been reported. Overdosage with phentolamine is characterized chiefly by cardiovascular disturbances, such as arrhythmias, tachycardia, hypotension, and possibly shock. Other possible signs and symptoms include excitation, headache, sweating, pupillary contraction, visual disturbances, nausea, vomiting, diarrhea, and hypoglycemia.
There is no specific antidote: Treatment consists of appropriate monitoring and supportive care. A plasma expander and norepinephrine may be administered to manage decreased blood pressure.
[L48415][L48420]
Some evidence suggests that phentolamine also stimulates beta-adrenergic receptors, thereby causing peripheral vasodilation.[A261781] Phentolamine was shown to stimulate insulin secretion, possibly related to its blocking actions on ATP-sensitive K+ channels.[A261781][A261761]
How the body processes this drug — absorption, distribution, metabolism, and elimination
[L48415]
Following topical ocular administration of phentolamine ophthalmic solution 0.75%, the peak concentration levels were achieved between 15 minutes and one hour after dosing with the median value of 0.45 ng/mL.
[L48390]
[L48420]
The terminal elimination half-life of phentolamine was approximately two to three hours following submucosal administration.
[L48415]
[A261766]
[L48420]
Proteins and enzymes this drug interacts with in the body
PMID:21645528
Positively regulates postnatal regression of retinal hyaloid vessels via suppression of VEGFR2/KDR activity, downstream of OPN5 (By similarity)
PMID:29286281 PMID:34815345
Inward rectifier potassium channels are characterized by a greater tendency to allow potassium to flow into the cell rather than out of it. Their voltage dependence is regulated by the concentration of extracellular potassium; as external potassium is raised, the voltage range of the channel opening shifts to more positive voltages. The inward rectification is mainly due to the blockage of outward current by internal magnesium.
Can be blocked by extracellular barium (By similarity). In pancreatic cells, it forms KATP channels with ABCC8/SUR1 .
PMID:29286281 PMID:34815345
Can form cardiac and smooth muscle-type KATP channels with ABCC9
ATC V03AB36
ATC C04AB01
Chemical identifiers
CAS, UNII, InChI Key and database cross-references
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Chemical identifiers
CAS, UNII, InChI Key and database cross-references
Linked compound data from DrugBank Open Data (CC BY-NC 4.0)
Phentolamine
Additional database identifiers
Drugs Product Database (DPD)
5974
ChemSpider
5571
BindingDB
31046
Guide to Pharmacology
502
ZINC
ZINC000000020251
HUGO Gene Nomenclature Committee (HGNC)
HGNC:277
GenAtlas
ADRA1A
GeneCards
ADRA1A
GenBank Gene Database
D25235
GenBank Protein Database
433201
Guide to Pharmacology
22
UniProt Accession
ADA1A_HUMAN
HUGO Gene Nomenclature Committee (HGNC)
HGNC:278
GenAtlas
ADRA1B
GeneCards
ADRA1B
GenBank Gene Database
M99589
Guide to Pharmacology
23
UniProt Accession
ADA1B_HUMAN
HUGO Gene Nomenclature Committee (HGNC)
HGNC:280
GenAtlas
ADRA1D
GeneCards
ADRA1D
GenBank Gene Database
M76446
GenBank Protein Database
177807
Guide to Pharmacology
24
UniProt Accession
ADA1D_HUMAN
HUGO Gene Nomenclature Committee (HGNC)
HGNC:281
GenAtlas
ADRA2A
GeneCards
ADRA2A
GenBank Gene Database
M23533
GenBank Protein Database
178196
Guide to Pharmacology
25
UniProt Accession
ADA2A_HUMAN
HUGO Gene Nomenclature Committee (HGNC)
HGNC:282
GenAtlas
ADRA2B
GeneCards
ADRA2B
GenBank Gene Database
M34041
GenBank Protein Database
178198
Guide to Pharmacology
26
UniProt Accession
ADA2B_HUMAN
HUGO Gene Nomenclature Committee (HGNC)
HGNC:283
GenAtlas
ADRA2C
GeneCards
ADRA2C
GenBank Gene Database
J03853
GenBank Protein Database
178194
Guide to Pharmacology
27
UniProt Accession
ADA2C_HUMAN
HUGO Gene Nomenclature Committee (HGNC)
HGNC:3023
GenAtlas
DRD2
GeneCards
DRD2
GenBank Gene Database
M30625
GenBank Protein Database
181432
Guide to Pharmacology
215
UniProt Accession
DRD2_HUMAN
HUGO Gene Nomenclature Committee (HGNC)
HGNC:6257
GenAtlas
KCNJ11
GeneCards
KCNJ11
GenBank Gene Database
D50582
GenBank Protein Database
1088445
UniProt Accession
KCJ11_HUMAN
DrugBank citations
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Structured knowledge from the free knowledge base
Linked open data from Wikidata (Q420360), a free and open knowledge base operated by the Wikimedia Foundation. Data is available under the Creative Commons CC0 1.0 Public Domain Dedication. WHO INN from the World Health Organization.