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Polythiazide / prazosin Pregnancy and Breastfeeding Warnings

Polythiazide / prazosin is also known as: Minizide

Polythiazide / prazosin Pregnancy Warnings

Use of prazosin combined with oxprenolol during human pregnancy has been reported. The population studied consisted of 44 pregnant women, 25 of whom had severe hypertension, and 19 of whom had severe hypertension, edema, and proteinuria. There were three intrauterine deaths that were considered related to underlying diseases and not to drug therapy. One infant who suffered intrauterine growth retardation died postpartum after elective Cesarean section at 27 weeks' gestation. This growth retardation was an expected finding given the underlying condition of the mother and the population studied. The overall fetal survival rate of 78% was consider acceptable relative to untreated hypertensive pregnancy fetal survival rates. In short, no reports of adverse sequelae to the fetus attributable to prazosin have been reported. The Collaborative Perinatal Project monitored 50,282 mother-child pairs, of whom 233 were exposed to thiazide or related diuretics during the first trimester. An increased risk of malformations was found for thiazide diuretics, although the fact that the population studied had underlying cardiovascular disease makes implication of drug use alone difficult. Use of thiazides after the first trimester does not seem to carry this risk. Thiazide diuretics may, however, pose metabolic risks to the mother and fetus (hyponatremia, hypokalemia, thrombocytopenia, hyperglycemia), and may have a direct effect on smooth muscle, resulting in inhibition of labor. The Michigan Medicaid surveillance study showed no association between some thiazide diuretics and congenital defects (written communication, Franz Rosa, MD, Food and Drug Administration, 1994). This report is a summary of information from two studies, one in which 390 of 104,000 pregnant women from 1985 to 1992 received a related drug, hydrochlorothiazide (HCTZ). In the first study 28 total defects and 6 cardiovascular defects were observed (25 and 4 were expected, respectively). In the second study, 24 total defects and 7 cardiovascular defects were observed (22 and 6 were expected, respectively). Cleft palate was not observed in either study. These data do not support an association between HCTZ and congenital defects, and are considered pertinent to other thiazide diuretics. Cases of neonatal thrombocytopenia associated with the antepartum administration of thiazide diuretics have been reported.

Prazosin-polythiazide has been assigned to pregnancy category C by the FDA. Animal studies have failed to reveal evidence of teratogenicity after prazosin was administered at doses more than 225 times the maximum recommended human dose (MRHD, on a per kg basis). The addition of polythiazide may be significant since an increased number of stillbirths, longer gestation, and decreased survival of pups to weaning were observed after the combination drug was administered in oral doses 8 times (prazosin) and 40 times (polythiazide) the respective MHRD's. Animal studies have failed to reveal evidence of teratogenicity after prazosin-polythiazide was administered in doses 100 times the MRHD to rabbits or rats. No controlled data are available from human pregnancy, but studies in which prazosin was administered during human pregnancy show only maternal tachycardia and no teratogenic effects. Prazosin-polythiazide should only be given during pregnancy when there are no alternatives and benefit outweighs risk.

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Polythiazide / prazosin Breastfeeding Warnings

The manufacturer states that small amounts of prazosin are excreted into human milk. No reports of the use of prazosin during breast-feeding have been found. Caution is recommended when prazosin is administered to a nursing mother. While there are no data on polythiazide, many other thiazide diuretic agents are known to be excreted into human milk in low concentrations. A rare case of thrombocytopenia has been reported in one nursing infant whose mother was taking a related drug, chlorothiazide, but adverse effects in the nursing infant associated with thiazides, in general, are unlikely. Although some thiazides such as chlorothiazide are considered compatible with breast-feeding by the American Academy of Pediatrics, some manufacturers recommend 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. Mulley BA, Parr GD, Pau WK, Rye RM, Mould JJ, Sidle NC "Placental transfer of chlorthalidone and its elimination in maternal milk." Eur J Clin Pharmacol 13 (1978): 129-31
  2. Harley JD, Robin H, Robertson SE "Thiazide-induced neonatal haemolysis?" Br Med J 1 (1964): 696-7
  3. Lammintausta R, Erkkola R, Eronen M "Effect of chlorthiazide treatment on renin-aldosterone system during pregnancy." Acta Obstet Gynecol Scand 57 (1978): 389-92
  4. Lindheimer MD, Katz AI "Sodiuim and diuretics in pregnancy." N Engl J Med 288 (1973): 891-4
  5. Finnerty FA "Thiazide and neonatal thrombocytopenia." N Engl J Med 271 (1964): 160-1
  6. Gjonnaess H "Thiazide treatment in pregnancy with special reference to maternal and foetal electrolytes." Acta Obstet Gynecol Scand 47 (1968): 404-19
  7. Weseley AC, Douglas GW "Continuous use of chlorothiazide for prevention of toxemia of pregnancy." Obstet Gynecol 19 (1962): 355-8
  8. Goldman JA, Neri A, Ovadia J, Eckerling B, Vries A, de "Effect of chlorothiazide on intravenous glucose tolerance in pregnancy." Am J Obstet Gynecol 105 (1969): 556-60
  9. Menzies DN "Controlled trial of chlorothiazide in treatment of early pre-eclampsia." Br Med J 1 (1964): 139-42
  10. Sibai BM, Grossman RA, Grossman HG "Effects of diuretics on plasma volume in pregnancies with long-term hypertension." Am J Obstet Gynecol 150 (1984): 831-5
  11. Gray MJ "Use and abuse of thiazides in pregnancy." Clin Obstet Gynecol 11 (1968): 568-78
  12. Watt JD "Oral diuretics in pregnancy toxaemia." Br Med J 1 (1960): 1807
  13. Crosland DM, Flowers CE "Chlorothiazide and its relationship to neonatal jaundice." Obstet Gynecol 22 (1963): 500-4
  14. Shoemaker ES, Gant NF, Madden JD, MacDonald PC "The effect of thiazide diuretics on placental function." Tex Med 69 (1973): 109-15
  15. Lubbe WF, Hodge JV "Combined a- and B-adrenoceptor antagonism with prazosin and oxprenolol in control of severe hypertension in pregnancy." N Z Med J 94 (1981): 169-72
  16. Flowers CE, Grizzle JE, Easterling WE, Bonner B "Chlorothiazide as a prophylaxis against toxemia of pregnancy." Am J Obstet Gynecol 84 (1962): 919-29
  17. Leikin SL "Thiazide and neonatal thrombocytopenia." N Engl J Med 271 (1964): 161
  18. Tatum HJ, Waterman EA "The prophylactic and therapeutic use of the thiazides in pregnancy." GP 24 (1961): 101-5
  19. Jerkner K, Kutti J, Victorin L "Platelet counts in mothers and their newborn infants with respect to ante-partum administration of oral diuretics." Acta Med Scand 194 (1973): 473-5
  20. Rodriguez SU, Sanford LL, Hiller MC "Neonatal thrombocytopenia associated with ante-partum administration of thiazide drugs." N Engl J Med 270 (1964): 881-4
  21. Zuspan FP, Bell JD, Barnes AC "Balance-ward and double-blind diuretic studies during pregnancy." Obstet Gynecol 16 (1960): 543-9
  22. "Product Information. Minizide (prazosin-polythiazide)." Pfizer US Pharmaceuticals, New York, NY.
  23. Garnet JD "Placental transfer of chlorothiazide." Obstet Gynecol 21 (1963): 123-5
  24. Ladner CN, Pearson JW, Herrick CN, Harrison HE "The effect of chlorothiazide on blood glucose in the third trimester of pregnancy." Obstet Gynecol 23 (1964): 555-60
  25. "Product Information. Diuril (chlorothiazide)." Merck & Co, Inc, West Point, PA.
  26. Minkowitz S, Soloway HB, Hall JE, Yermakov V "Fatal hemorrhagic pancreatitis following chlorothiazide administration in pregnancy." Obstet Gynecol 24 (1964): 337-42
  27. Prescott LF "Neonatal thrombocytopenia and thiazide drugs." J Pediatr 67 (1965): 681-2
  28. Pritchard JA, Walley PJ "Severe hypokalemia due to prolonged administration of chlorothiazide during pregnancy." Am J Obstet Gynecol 81 (1961): 1241-4
  29. Venuto R, Burstein P, Schneider R "Phenochromocytoma: antepartum diagnosis and management with tumor resection in the puerperium." Am J Obstet Gynecol 150 (1984): 431-2
  30. Jerkner K, Kutti J, Victorin L "Platelet counts in mothers and their newborn infants with respect to ante-partum administration of oral diuretics." Acta Med Scand 194 (1973): 473-5

References for breastfeeding information

  1. Mulley BA, Parr GD, Pau WK, Rye RM, Mould JJ, Sidle NC "Placental transfer of chlorthalidone and its elimination in maternal milk." Eur J Clin Pharmacol 13 (1978): 129-31
  2. Werthmann MW, Krees SV "Excretion of chlorothiazide in human breast milk." J Pediatr 81 (1972): 781-3
  3. "Product Information. Minizide (prazosin-polythiazide)." Pfizer US Pharmaceuticals, New York, NY.
  4. Miller ME, Cohn RD, Burghart PH "Hydrochlorothiazide disposition in a mother and her breast-fed infant." J Pediatr 101 (1982): 789-91

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