Phentolamine
Phentolamine mesylate is an alpha-adrenergic blocking agent used primarily in dentistry to reverse soft-tissue anesthesia and reduce associated functional deficits such as lip and cheek numbness following dental procedures. It works by blocking alpha-adrenergic receptors, causing vasodilation and increased blood flow to the affected area.
Phentolamine is a short-acting alpha-blocker used to reverse local anesthesia in dental patients.
Key facts at a glance
- ATC
- C04AB01
- RxNorm
- 8153
- Generic
- Phentolamine
- Class
- atc-c04
- Brands
- Ryzumvi, OraVerse
- Availability
- rx
- Pregnancy
- C
- Lactation
- caution
- Routes
- ophthalmic
- Forms
- solution, injection
- Regions
- US, EU, CN, JP
- Monitoring
- —
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Dosage and administration
- Usual dose
- 500mg twice daily
- Maximum
- consult physician
- Frequency
- every 12 hours
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 250mg twice daily
- Maximum
- consult physician
- Frequency
- every 12 hours
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 400mg daily
- Maximum
- consult physician
- Frequency
- once daily
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
Overdose information
Special Populations
10 groupspregnancy
first trimesteravoid if possible
use only if potential benefits justify potential risk to fetus; consider alternative therapies
regular fetal monitoring and ultrasound assessments
Use with caution and monitor for adverse effects.
pregnancy
second trimesteruse lowest effective dose
use only when absolutely necessary for maternal indication; weigh risks and benefits carefully
fetal heart rate monitoring and growth assessments
Use with caution and monitor for adverse effects.
pregnancy
third trimesteruse lowest effective dose
discontinue if possible before delivery; use only for severe hypertension
close fetal monitoring and uterine activity assessment
Use with caution and monitor for adverse effects.
lactation
breastfeedinguse with caution
discontinue breastfeeding or pump and discard milk during treatment and for 24 hours after administration
observe infant for adverse effects
geriatric
elderlystart with lower dose and titrate slowly
use reduced initial dose; monitor blood pressure closely for orthostatic hypotension
regular blood pressure monitoring, renal function assessment
Use with caution and monitor for adverse effects.
pediatric_age
children 2 12 yearsweight-based dosing; reduce dose
use only for specific indications; pediatric use based on limited clinical data
close blood pressure and heart rate monitoring
Use with caution and monitor for adverse effects.
renal_impairment
mild to moderatemay require dose reduction
use with caution; monitor renal function and blood pressure
monitor renal function, serum electrolytes, blood pressure
Use with caution and monitor for adverse effects.
renal_impairment
severesignificant dose reduction recommended
use with extreme caution; consider alternative therapies if available
frequent renal function monitoring, blood pressure checks, ECG monitoring
Use with caution and monitor for adverse effects.
hepatic_impairment
mild to moderatemay require dose reduction
use with caution; monitor liver function tests
liver function tests, blood pressure monitoring
Use with caution and monitor for adverse effects.
hepatic_impairment
severesignificant dose reduction required
use only if absolutely necessary; consider alternative therapies
frequent liver function monitoring, blood pressure and heart rate monitoring
Use with caution and monitor for adverse effects.
Statistics and clinical data
Drug class
Non-selective alpha-1 and alpha-2 adrenergic receptor blocker
Mechanism of action
Blocks alpha-1 and alpha-2 receptors causing vasodilation
Common uses
Therapeutic applications
FDA approval OraVerse
Dental anesthetic reversal agent approval
Reversal of soft-tissue anesthesia and functional deficits (lip numbness, cheek numbness) following dental procedures using local anesthetics with vasoconstrictors. May also be used off-label for hypertensive emergencies and pheochromocytoma management.
Phentolamine mesylate competitively blocks alpha-adrenergic receptors (both alpha-1 and alpha-2), preventing catecholamine binding and resulting in smooth muscle relaxation, vasodilation, and increased peripheral blood flow. This action reverses the vasoconstrictive effects of local anesthetics and accelerates restoration of normal sensation.
Short duration of action limits systemic effects. Contraindicated in patients with hypersensitivity to phentolamine or related compounds. Use cautiously in patients with cardiovascular disease, as it may cause hypotension or tachycardia. Safety in pregnancy and nursing has not been established. Onset is rapid when administered locally.
Contraindications
Conditions and patient states where this medication should be avoided or used with caution.
Do not use (1)
Known allergy to this medication or its components
Use caution (1)
Consult healthcare provider for benefits vs risks assessment
Official drug label
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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed July 26, 2026. · Read our editorial policy