phentolamine (Regitine, OraVerse)
Classes: Alpha Blockers, Antihypertensives; Extravasation Antidotes
Dosing and uses of Regitine, OraVerse (phentolamine)
Adult dosage forms and strengths
powder for injection
- 5mg
injectable solution
- 0.4mg/1.7mL
Pheochromocytoma
Diagnosis: 5 mg IV/Im
Test for pheochromocytoma is positive if decrease SBP >35 mmHg & decrease DBP >25 mmHg
Pheochromocytoma Surgery Use
Treatment of hypertension during pheochromocytoma surgery
5 mg IV/IM 1-2 hr preoperative, repeat if necessary q2-4hr
Extravasation Treatment
Epinephrine or norepinephrine extravastation treatment
Treatment: 5-10 mg in 10 mL NS local injection within 12 hr
Prevention: 10 mg for each liter of IV fluids (pressor effect of NE is unaffected)
Dental Anesthesia Reversal (OraVerse)
Indicated for reversal of soft-tissue anesthesia associated with functional deficits from intraoral local anesthesia containing a vasoconstrictor
Dose based on amount of local anesthetic administered
Administer using same locations and techniques (infiltration or block injection) as local anesthetic
1/2 cartridge local anesthetic: OraVerse 1/2 cartridge (0.2 mg)
1 cartridge local anesthetic: OraVerse 1 cartridge (0.4 mg)
2 cartridges local anesthetic: OraVerse 2 cartridges (0.8 mg)
Hypertensive Crises (Off-label)
Secondary to catecholamine excess: 5-15 mg IV
Other Indications & Uses
Pheochromocytoma diagnosis, HTN in pheochromocytoma surgery, dermal necrosis due to epinephrine/NE extravasation
Off-label: hypertensive crises (pheochromocytoma, other catecholamine excess situations); erectile dysfunction (intracavernous)
Pediatric dosage forms and strengths
powder for injection
- 5mg
injectable solution
- 0.4mg/1.7mL
Pheochromocytoma, Diagnosis
0.1-0.2 mg/kg IV/IM, OR 1 mg IV OR 3 mg Im
Pheochromocytoma Surgery Use
Treatment of hypertension during surgery
0.05-0.1 mg/kg/dose OR 1 mg IV/IM 1-2 hr preoperative, repeat q2-4hr until hypertension is controlled; not to exceed 5 mg/dose
Dental Anesthesia Reversal (OraVerse)
Indicated for reversal of soft-tissue anesthesia associated with functional deficits from intraoral local anesthesia containing a vasoconstrictor
<6 years or <15 kg: Safety and efficacy not established
Dose based on amount of local anesthetic administered
Administer using same locations and techniques (infiltration or block injection) as local anesthetic
6-12 years (15-30 kg)
- For 1/2 cartridge local anesthetic, use OraVerse 1/2 cartridge (0.2 mg)
6-12 years (>30 kg)
- 1/2 cartridge local anesthetic: OraVerse 1/2 cartridge (0.2 mg)
- 1 cartridge local anesthetic: OraVerse 1 cartridge (0.4 mg)
Other Information
Extravasation of epinephrine/norepinephrine:0.1-0.2 mg/kg to no more than 10 mg
Geriatric dosage forms and strengths
Pheochromocytoma
Diagnosis: 5 mg IV/Im
Test for pheochromocytoma is positive if decrease SBP >35 mmHg & decrease DBP >25 mmHg
Pheochromocytoma surgery use
Treatment of hypertension during pheochromocytoma surgery
5 mg IV/IM 1-2 hr preoperative, repeat if necessary q2-4hr
Extravasation treatment
Epinephrine or norepinephrine extravastation treatment
Treatment: 5-10 mg in 10 mL NS local injection within 12 hr
Prevention: 10 mg for each liter of IV fluids (pressor effect of NE is unaffected)
Dental anesthesia reversal (OraVerse)
Indicated for reversal of soft-tissue anesthesia associated with functional deficits from intraoral local anesthesia containing a vasoconstrictor
Dose based on amount of local anesthetic administered
Administer using same locations and techniques (infiltration or block injection) as local anesthetic
1/2 cartridge local anesthetic: OraVerse 1/2 cartridge (0.2 mg)
1 cartridge local anesthetic: OraVerse 1 cartridge (0.4 mg)
2 cartridges local anesthetic: OraVerse 2 cartridges (0.8 mg)
Regitine, OraVerse (phentolamine) adverse (side) effects
1-10%
Nasal congestion (10% )
Post-treatment pain (up to 10% )
Injection site pain (4% to 6% )
Diarrhea (<3% )
Frequency not defined
Cardiac dysrhythmia
Chest pain
Hypotension
Myocardial infarction
CVA - cerebrovascular accident due to cerebral artery occlusion
Warnings
Contraindications
Hypersensitivity; MI or other CAd
Cautions
First dose effect may occur, causing a sudden and drastic fall in blood pressure after administering the first dose.
Hypotension/syncope with first few doses or with increase in dose
Minimize by using small first dose at bedtime
Increase dose slowly
Pregnancy and lactation
Pregnancy category: C
Lactation: not known if excreted in breast milk; not recommended
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of Regitine, OraVerse (phentolamine)
Mechanism of action
Has positive inotropic and chronotropic effect on the heart
Blocks alph-adrenergic receptors to briefly antagonize circulating epinephrine and norepinephrine to reduce hypertension caused by alpha effects of the endogenous catecholamines
Pharmacokinetics
Half-Life:19 min (IV)
Duration: 30-45 min (IM); 15-30 min (IV)
Excretion: Urine (13%) as unchanged drug
Metabolism: Hepatic
Onset of action: Immediate (IV); 15-20 min (IM)
Peak effect: 10-20 min (OraVerse)
Administration
IV Compatibilities
Additive: cibenzoline succinate, dobutamine, verapamiL
Syringe: papaverine
Y-site: amiodarone
IV Preparation
Reconstitute with 1 mL SWI (5 mg/mL solution)
IV/IM Administration
Administer by IV or IM injection
Rapid IV
Storage
Store at controlled room temperature
