Pharm

Hydrochlorothiazide

search

Hydrochlorothiazide, HCTZ, Esidrex, HydroDIURIL

  • See Also
  1. Thiazide Diuretic
  • Indications
  1. Hypertension
  • Contraindications
  1. Hypercalcemia
  2. Gouty Arthritis
  • Epidemiology
  1. Hydrochlorothiazide is the most commonly prescribed Thiazide Diuretic for Hypertension
  1. Start: 12 to 25 mg orally daily
  2. Typical maintenance dose 25 mg orally daily
  3. Maximum 50 mg/day
    1. Higher doses worsen Hypokalemia without additional Antihypertensive benefit
  4. Available as generic scored tablets (25 and 50 mg) and capsules (25 mg)
  • Medications
  • Combinations
  1. Many ACE and ARBs are combined with Hydrochlorothiazide
  2. Hydrochlorothiazide and Triamterene
    1. Hctz/Triamterene 25/50 (Dyazide) once daily
    2. Hctz/Triamterene 50/75 (Maxzide) once daily
  • Pharmacokinetics
  1. Renal excretion, unchanged in urine
  2. Onset of activity: 2 hours
  3. Shorter Half-Life (6-12 hours) than the 24 hour half life of Chlorthalidone and Indapamide
    1. Immediate release Hydrochlorothiazide may only reduce daytime systolic Blood Pressure
    2. Controlled release Hydrochlorothiazide (available outside the U.S.) has 24 hour activity
  • Efficacy
  1. Less potent than Chlorthalidone
    1. Chlorthalidone reduces systolic Blood Pressure 10 mmHg more than Hydrochlorothiazide
    2. However, Hydrochlorothiazide and Chlorthalidone are associated with similar cardiovascular outcomes
      1. Chlorthalidone also raises the risk of Hypokalemia
      2. Ishani (2022) N Engl J Med 387(26):2401-10 +PMID: 36516076 [PubMed]
  • Mechanism
  1. See Thiazide Diuretic
  • Adverse Effects
  1. See Thiazide Diuretic
  • Safety
  1. Considered Safe in Lactation
  2. Pregnancy Category B
    1. Pregnancy Category D for Pregnancy Induced Hypertension
    2. See Thiazide Diuretic
  • Drug Interactions
  1. Cyclosporine
    1. Increased risk of Hypercalcemia, Gouty Arthritis
  2. Corticosteroids
    1. Increased risk of Hypokalemia
  3. Cytotoxic medications (e.g. Cyclophosphamide, Methotrexate)
    1. Hydrochlorothiazide may decrease renal excretion of cytotoxic medications
  • Resources
  1. Hydrochlorothiazide (DailyMed)
    1. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=c59c4230-7cea-4259-9f2f-6a568716fedf
  • References
  1. (2021) Presc Lett, Resource #370507, Commonly Used Diuretics
  2. (2020) Med Lett Drugs Ther 62(1598): 73-80
  3. Olson (2020) Clinical Pharmacology, Medmaster Miami, p. 62-3
  4. Hamilton (2020) Tarascon Pocket Pharmacopoeia