Hydrochlorothiazide (HCTZ) and Triamterene are commonly prescribed together to treat conditions like high blood pressure and fluid retention. HCTZ is a thiazide diuretic that helps the body remove excess sodium and water, while Triamterene is a potassium-sparing diuretic that prevents potassium loss during this process, balancing the body’s electrolytes. HCTZ removes excess fluid and Triamterene prevents potassium loss.

Mechanisms of Action
⦁ HCTZ: Increases urine output by blocking sodium reabsorption in the kidneys, reducing fluid retention and lowering blood pressure.

Contraindications & Precautions
⦁ Contraindications: Allergy to HCTZ, triamterene, or sulfonamides, anuria, severe kidney or liver disease, hyperkalemia, pregnancy (especially 1st trimester), and breastfeeding.
⦁ Precautions: Use cautiously in kidney disease, monitor for electrolyte imbalances, and in diabetes.

Interactions
⦁ Potassium-sparing diuretics may increase the risk of hyperkalemia.
⦁ ACE inhibitors, ARBs, and NSAIDs may affect blood pressure and potassium levels.
⦁ Lithium: HCTZ may increase lithium levels.

Adverse Reactions / Side Effects
⦁ Common: Dizziness, increased urination, electrolyte imbalances.
⦁ Serious: Hyperkalemia (high potassium), kidney dysfunction, gout attacks.

Pregnancy & Breastfeeding
⦁ Pregnancy: Not recommended during the first trimester.
⦁ Breastfeeding: Not recommended due to potential risks to the infant.

Store this medication at 68°F to 77°F (20°C to 25°C) and away from heat, moisture and light. Keep all medicine out of the reach of children. Throw away any unused medicine after the beyond use date. Do not flush unused medications or pour down a sink or drain.

1. Welling PG. Pharmacokinetics of the thiazide diuretics. Biopharm Drug Dispos 1986;7:501-35.
2. Neimeyer C, Hasenfuss G, Wais U, et al. Pharmacokinetics of hydrochlorothiazide in relation to renal function. Eur J Clin Pharmacol 1983;24:661-5. Abstract.
3. Freis ED. Critique of the clinical importance of diurectic-induced hypokalemia and elevated cholesterol level. Arch Intern Med 1989;149:2640-8.
4. Sullivan TJ. Cross-reactions among furosemide, hydrochlorothiazide, and sulfonamides. JAMA 1991;265:120-1.
5. Knowles S, Shapiro L, Shear NH. Should celecoxib be contraindicated in patients who are allergic to sulfonamides? Revisiting the meaning of “sulfa” allergy. Drug Saf 2001;24:239-247.
6. Johnson KK, Green DL, Rife JP, et al. Sulfonamide cross-reactivity: fact or fiction? Ann Pharmacother 2005;39:290-301.
7. Verdel BM, Souverein PC, Egberts AC, et al. Difference in risks of allergic reaction to sulfonamide drugs based on chemical structure. Ann Pharmacother 2006;40:1040-6.
8. Strom BL, Schinnar R, Apter AJ, et al. Absence of cross-reactivity between sulfonamide antibiotics and sulfonamide nonantibiotics. New Engl J Med 2003;349:1628-35.
9. Amturnide (aliskiren; amlodipine; hydrochlorothiazide) package insert. East Hanover, NJ: Novartis; 2014 Mar.
10. Dyazide (hydrochlorothiazide; triamterene) oral capsules package insert. Research Triangle Park, NC: GlaxoSmithKline; 2011 Feb.
11. Poon IO, Braun U. High prevalence of orthostatic hypotension and its correlation with potentially causative medications among elderly veterans. J Clin Pharm Ther 2005;30:173-8.
12. American Geriatrics Society, British Geriatrics Society, American Academy of Orthopaedic Surgeons Panel on Falls Prevention. Guideline for the prevention of falls in older persons. J Am Geriatr Soc 2001;49:664-72.
13. Leipzig RM, Cumming RG, Tinetti ME. Drugs and falls in older people: a systematic review and meta-analysis: II. Cardiac and analgesic drugs. J Am Geriatr Soc 1999;47:40-50.
14. ACOG Committee on Practice Bulletins. Chronic hypertension in pregnancy. Obstet Gynecol 2001;98:suppl 177-85.
15. Report of the National High Blood Pressure Education Program Working Group on High Blood Pressure in Pregnancy. Am J Obstet Gynecol 2000;183:S1-S22.
16. Hydrochlorothiazide and triamterene tablet package insert. Corona, CA: Watson Pharma, Inc.; 2008 Dec.
17. American Academy of Pediatrics (AAP) Committee on Drugs. Transfer of drugs and other chemicals into human milk. Pediatrics 2001;108:776-89.
18. Moore DE. Drug-induced cutaneous photosensitivity: incidence, mechanism, prevention and management. Drug Saf 2002;25:345-72.
19. Fuhr U, Kober S, Zaigler M, et al. Rate-limiting biotransformation of triamterene is mediated by CYP1A2. Int J Clin Pharmacol Ther 2005;43:327—34.
20. HydroDIURIL® (hydrochlorothiazide) package insert. Whitehouse Station, NJ: Merck & Co., Inc.; 1998 Jun.
21. Tsiodras S, Mantzoros C, Hammer S, et al. Effects of protease inhibitors on hyperglycemia, hyperlipidemia, and lipodystrophy: a 5-year cohort study. Arch Intern Med 2000;160(13):2050-2056.
22. Seamans KB, Gloor P, Dobell RA, et al. Penicillin-induced seizures during cardiopulmonary bypass: a clinical and electroencephalographic study. N Engl J Med 1968;278(16):861-868.
23. Lovallo W, Wilson MF, Vincent AS, et al: Blood pressure response to caffeine shows incomplete tolerance after short-term regular consumption. Hypertension 2004;43:760-765.
24. Visicol® (sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous) package insert. Morrisville, NC: Salix Pharmaceuticals, Inc.; 2006 Mar.
25. Osmoprep® (sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous) package insert. Morrisville, NC: Salix Pharmaceuticals, Inc.; 2006 Mar.
26. Rothkopf M, Vogel G, Lang W et al. Animal experiments on the question of the renal toleration of the horse chestnut saponin aescin. Arneimittelforschung 1977;27:598—605.
27. Renova® 0.05% (tretinoin emollient cream) package insert. Raritan, NJ: Ortho Dermatological; 1998 Feb.
28. Tazorac® (tazarotene) gel package insert. Irvine CA: Allergan, Inc.; 1998 Dec.
29. Tazorac® (tazarotene) cream package insert. Irvine CA: Allergan, Inc.; 2001 Oct.
30. Moore DE. Drug-induced cutaneous photosensitivity: incidence, mechanism, prevention and management. Drug Saf 2002;25:345—72. Review.
31. Cohn JN, Kowey PR, Whelton PK, Prisant LM. New guidelines for potassium replacement in clinical practice: a contemporary review by the National Council on Potassium in Clinical Practice. Arch Intern Med 2000;160:2429-2436.
32. Baraclude™ (entecavir) package insert. Princeton, NJ: Bristol-Myers Squibb Company; 2007 Jul.
33. Bendayan R. Renal drug transport: A review. Pharmacotherapy 1996;16:971—85.
34. Nardil® (phenelzine) package insert. New York, NY: Pfizer; 2003.
35. Parnate® (tranylcypromine) package insert. Research Triangle Park, NC: GlaxoSmithKline; 2001 Aug.
36. Cohn JN, Kowey PR, Whelton PK, Prisant LM. New guidelines for potassium replacement in clinical practice: a contemporary review by the National Council on Potassium in Clinical Practice. Arch Intern Med 2000;160:2429—36.
37. Nanji AA. Drug-induced electrolyte disorders. Drug Intell Clin Pharm 1983;17:175—85.
38. Cordarone® (amiodarone) package insert. Philadelphia, PA: Wyeth Laboratories; 2007 Mar.
39. Yassa R, Nastase C, Camille Y, et al. Carbamazepine, diuretic, and hyponatremia: a possible interaction. J Clin Psychiatry 1987;48:281—3.
40. Ranta A and Wooten GF. Hyponatremia due to an additive effect of carbamazepine and thiazide diuretics. Epilepsia 2004;45:879.
41. Diflucan® (fluconazole) package insert. New York, NY. Pfizer; 2004 Aug.
42. Topamax® (topiramate) package insert. Raritan, NJ: Ortho-McNeil Pharmaceutical, Inc.; 2005 June.
43. Hollenberg NK, Mickiewicz CW. Postmarketing surveillance in 70,898 patients treated with triamterene/hydrochlorothiazide combination (Maxide). Am J Cardiol 1989;63:37B-41B.
44. Children’s Allegra Allergy (fexofenadine hcl) oral suspension package insert. Bridgewater, NJ: Sanofi-Aventis; 2011 Jan.
45. Houston MC. New insights and new approaches for the treatment of essential hypertension: selection of therapy based on coronary heart disease risk factor analysis, hemodynamics profiles, quality of life, and subsets of hypertension. Am Heart J 1989;117:91
46. Greenberg A. Diuretic complications. Am J Med Sci 2000;319:10-24.