Skip to main content

Phentolamine Pregnancy and Breastfeeding Warnings

Phentolamine is also known as: OraVerse, Regitine

Phentolamine Pregnancy Warnings

Phentolamine has been assigned to pregnancy category C by the FDA. Animal data have revealed slightly decreased growth and slight skeletal immaturity of the fetuses after rats and mice were given doses 24 to 30 times the usual daily human doses (UDHD, on a per kg basis). At oral doses 60 times the UDHD (on a per kg basis), a slightly lower rate of implantation was found in the rat. Phentolamine did not affect embryonic or fetal development in the rabbit at oral doses 20 times the UDHD. No teratogenic or embryotoxic effects were observed in any of the animal studies. There are no reports of adverse effects on the fetus from isolated cases in which the drug has been used to treat pheochromocytoma during human pregnancy. There are no controlled in human pregnancy. Phentolamine is only recommended for use during pregnancy when benefit outweighs risk.

The relationship between with the use of phentolamine and maternal or fetal mortality in patients with pheochromocytoma is not clear because of the significant mortality associated with this tumor. Some experts recommend caution if phentolamine must be used during pregnancy because of the risk of hypotension and decreased placental perfusion pressure. Use of this drug during pregnancy should, therefore, be limited to the treatment of acute episodes of hypertension in patients with pheochromocytoma and for the immediate preoperative and intraoperative management of such a patient undergoing Cesarean section and/or removal of the pheochromocytoma.

Phentolamine is not recommended as a diagnostic agent during pregnancy because of the availability of safer methods (urinary catecholamine levels). It is also not recommended for the chronic management of pheochromocytoma during pregnancy.

Phentolamine does not appear to adversely affect uterine contractility.

Animal studies have revealed evidence of skeletal immaturity associated with phentolamine. Immaturity was manifested by an increased incidence of incomplete or unossified calcaei and phalangeal nuclei of the hind limb and of incompletely ossified sternabrae.

See references

Phentolamine Breastfeeding Warnings

There are no data on the excretion of phentolamine into human milk. The manufacturer recommends that due to the potential for serious adverse reactions in nursing infants, a decision should be made to discontinue nursing or discontinue the drug, taking into account the importance of the drug to the mother.

See references

References for pregnancy information

  1. Coustan D, Berkowitz R, Mochizuki T. "Handbook for Prescribing Medications During Pregnancy." Boston, MA: Little, Brown, and Company (1986): 242
  2. Batts JA Jr, Tchilinguirian NG, Passmore J "Pheochromocytoma in pregnancy: a case report and review of the pathophysiology." Am J Obstet Gynecol 118 (1974): 576-7
  3. Brenner WE, Yen SS, Dingfelder JR, Anton AH "Pheochromocytoma: serial studies during pregnancy." Am J Obstet Gynecol 113 (1972): 779-88
  4. Hendee AE, Martin RD, Waters WC 3d "Hypertension in pregnancy: toxemia or pheochromocytoma?" Am J Obstet Gynecol 105 (1969): 64-72
  5. Barden TP, Stander RW "Effects of adrenergic blocking agents and catecholamines in human pregnancy." Am J Obstet Gynecol 102 (1968): 226-35
  6. Thiery M, Derom RM, Van Kets HE, De Schaepdryver AF, Bernard PJ, Bekaert SA, Hooft CM, Derom F, Rolly G, Roels HJ "Pheochromocytoma in pregnancy including observations on the physiopathology and the enzymic histochemistry of this tumor." Am J Obstet Gynecol 97 (1967): 21-9
  7. Wansbrough H, Nakanishi H, Wood C "The effect of adrenergic receptor blocking drugs on the human uterus." J Obstet Gynaecol Br Commonw 75 (1968): 189-98
  8. Burgess GE 3d "Alpha blockade and surgical intervention of pheochromocytoma in pregnancy." Obstet Gynecol 53 (1979): 266-70
  9. Vaczy L, Lenner A, Molnar A "Treatment of pregnancy toxaemia with alpha-blocking agents." Acta Chir Acad Sci Hung 12 (1971): 7-15
  10. Leak D, Carroll JJ, Robinson DC, Ashworth EJ "Management of pheochromocytoma during pregnancy." Obstet Gynecol Surv 32 (1977): 583-5
  11. "Product Information. Regitine (phentolamine)." Ciba-Geigy Pharmaceuticals (2001):
  12. Maughan GB "Experiments with pharmacologic sympatholysis in the gravid." Am J Obstet Gynecol 97 (1967): 664-76
  13. Althabe O, Schwarcz RL Jr, Sala NL, Fisch L "Effect of phentolamine methanesulfonate upon uterine contractility by I-norepinephrine pregnancy." Am J Obstet Gynecol 101 (1968): 1083-8
  14. Jenssen H "Inhibition of oxytocin-induced uterine activity in medpregnancy by combined adrenergic alpha-blockade and beta-stimulation." Acta Obstet Gynecol Scand 50 (1971): 135-9
  15. Schenker JG, Chowers I "Pheochromocytoma and pregnancy." Obstet Gynecol Surv 26 (1971): 739-47
  16. Smith AM "Phaeochromocytoma and pregnancy." J Obstet Gynaecol Br Commonw 80 (1973): 848-51
  17. Brenner WE, Yen SS, Dingfelder JR, Anton AH "Pheochromocytoma: serial studies during pregnancy." Am J Obstet Gynecol 113 (1972): 779-88
  18. Simanis J, Amerson JR, Hendee AE, Anton AH "Unresectable pheochromocytoma in pregnancy." Am J Med 53 (1972): 381-5
  19. Griffith MI, Fetts JH, James FM "Successful control of pheochromocytoma in pregnancy." JAMA 229 (1974): 437-9
  20. Briggs GG, Freeman RK, Yaffe SJ.. "Drugs in Pregnancy and Lactation." Baltimore, MD: Williams & Wilkins (1998):

References for breastfeeding information

  1. "Product Information. Regitine (phentolamine)." Ciba-Geigy Pharmaceuticals (2001):

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.