Hypodehydra (Hydrochlorothiazide)

Hydrochlorothiazide acts on the renal tubular system to lower blood pressure and reduce fluid overload, making it useful in several cardiovascular and renal conditions.

• Hypertension: helps lower systemic blood pressure by decreasing plasma volume.
• Congestive heart‑failure‑related edema: promotes removal of excess fluid, easing cardiac workload.
• Hepatic‑cirrhosis‑related edema: reduces ascites and peripheral swelling by increasing urinary output.
• Renal‑disease‑related edema: assists in fluid removal when kidney function is compromised.

• Hydrochlorothiazide inhibits the Na⁺/Cl⁻ symporter located in the distal convoluted tubule of the nephron. By blocking this transporter, sodium and chloride reabsorption are reduced, leading to increased urinary excretion of sodium, water, and accompanying electrolytes. The resultant decline in extracellular fluid volume lowers cardiac preload and systemic vascular resistance, producing a modest reduction in arterial blood pressure.

Hydrochlorothiazide may cause a range of adverse reactions, from mild to serious. Patients should be aware of both common and less frequent events.

Common Side Effects

• Dizziness or light‑headedness.
• Headache.
• Increased frequency of urination.
• Electrolyte disturbances, especially low potassium (hypokalemia).
• Mild hyperglycemia.
• Muscle cramps or weakness.

Serious or Rare Side Effects

• Severe dehydration or volume depletion.
• Marked electrolyte imbalances (e.g., hyponatremia, hypokalemia).
• Acute gout attacks.
• Pancreatitis.
• Allergic reactions such as rash, Stevens‑Johnson syndrome, or anaphylaxis.
• Blood dyscrasias like agranulocytosis or thrombocytopenia.

Before initiating therapy, clinicians should evaluate patient‑specific factors and monitor for potential complications.

• Electrolyte monitoring: regularly check serum potassium, sodium, and magnesium levels.
• Renal function: assess creatinine clearance, especially in patients with existing kidney disease.
• Gout risk: use caution in individuals with a history of gout, as uric acid may rise.
• Diabetes: monitor blood glucose, as thiazides can impair glucose tolerance.
• Pregnancy: category B; discuss benefits versus risks with the obstetric team.
• Store at ambient temperature below 25°C: keep in the original container, protect from moisture.

Hydrochlorothiazide can alter the pharmacokinetics or pharmacodynamics of several co‑administered medicines.

Major Interactions (Avoid)

• Lithium: thiazides reduce lithium clearance, increasing toxicity risk.
• Cyclosporine: may enhance nephrotoxic effects.
• High‑dose NSAIDs: can blunt diuretic efficacy and worsen renal function.

Moderate Interactions (Monitor Closely)

• Antidiabetic agents: may require dose adjustment due to altered glucose control.
• ACE inhibitors or ARBs: risk of additive potassium loss.
• Corticosteroids: can increase sodium loss and exacerbate hypokalemia.
• Other diuretics: combined use may lead to excessive volume depletion.