Chlorthalidone Pharmacological action
Chlorthalidone - like thiazides diuretic, has a long-term effect. Violates the reabsorption of sodium, chlorine, and equivalent amounts of water in the distal renal tubule. In addition, increases the excretion of potassium, magnesium, bicarbonate, delays excretion of uric acid, calcium ions. Refers to the diuretic-average performance. Diuretic effect begins after 2 h, reaching a peak after 12 hours and lasts up to 72 hours causes a decrease in high BP. Hypotensive effect develops gradually, reaching a peak after 2-4 weeks. after starting treatment. In addition, chlorthalidone causes a reduction of polyuria in patients with diabetes insipidus, although its mechanism of action has not been elucidated.
Chlorthalidone Pharmacokinetics
After oral chlorthalidone absorbed from the gastrointestinal tract. Absorption of a volatile nature. Highly associated with the erythrocytes is much less pronounced binding to plasma proteins.
T1 / 2 long, 40-60 pm
Is primarily excreted unchanged in urine.
Elderly patients breeding slows down, compared with patients young and middle age, absorption does not change.
Chlorthalidone Statement
Chronic heart failure, II Art., Hypertension, cirrhosis of the liver c portal hypertension, nephrosis, nephritis, late gestosis (nephropathy, edema, eclampsia), fluid retention with premenstrual syndrome, diabetes insipidus, disproteinemicheskie edema, obesity.
Chlorthalidone Dosing regimen
Set individually. Hypertension – 25 mg 1 time per day. If necessary, the dose may be increased to 50-100 mg / day. Upon reaching the effect of switching to maintenance therapy in the lowest effective dose. When edema syndrome is used in a dose of 50-100 mg 1 time per day., If necessary – up to 200 mg, after the effect of switching to maintenance therapy.
Chlorthalidone Side effect
From the digestive system: nausea, vomiting, diarrhea, constipation, loss of appetite.
CNS and peripheral nervous system: possible headache, weakness, paresthesias, dizziness.
From the water and electrolyte balance: possible hypokalemia, hypomagnesemia, hyponatremia, gipohloremichesky alkalosis, hypercalcemia.
From a metabolism: possible hyperuricemia, hyperglycemia.
From the hematopoietic system: rarely – thrombocytopenia, leukopenia.
Dermatological reactions: possible skin rash.
Chlorthalidone Contraindications
Anuria, severe renal and hepatic failure, hypokalemia, hyponatremia, hypercalcemia, hyperuricemia, gipohloremichesky alkalosis, hypertension during pregnancy, hypersensitivity to chlorthalidone and sulfonamides.
Chlorthalidone Application of pregnancy and breastfeeding
Crosses the placental barrier. When pregnancy is contraindicated in hypertension. In other cases, application is possible only under strict indications in the minimum effective doses and when the expected benefits of therapy to the mother justifies the potential risk to the fetus.
Chlorthalidone is excreted in breast milk. If necessary, use during lactation breastfeeding should be discontinued.
Cautions
During the period of treatment should be periodically determine blood electrolytes, particularly in patients taking digitalis preparations.
Not recommended for patients is very strict salt-free diet. If signs of hypokalemia (myasthenia, cardiac arrhythmias) or in the presence of patients with additional potential loss of K + (vomiting, diarrhea, malnutrition, liver cirrhosis, hyperaldosteronism, treatment with glucocorticoids or ACTH) shows replacement therapy with potassium. To prevent dehydration in severe nausea, vomiting or diarrhea occurs and continue to consult with your doctor.
Hyponatremia as a complication rarely noted, but if it develops quickly, it is a medical emergency.
Patients with hyperlipidemia should constantly monitor the level of lipids in the blood serum (in case of increase in their concentration therapy should be discontinued). While taking thiazide diuretics noted exacerbation of systemic lupus erythematosus, although such events when taking chlorthalidone is not found in his appointment to patients with this disease should use caution.
With careful use in patients with diabetes, gout, atherosclerosis of coronary and cerebral vascular disorders of the excretory kidney function in the elderly.
Chlorthalidone, especially early in treatment, may interfere with the ability to drive vehicles and management mechanisms.
Chlorthalidone Drug Interactions
In an application with corticosteroids, amphotericin B, carbenoxolone increased risk of severe hypokalemia.
In an application with NSAIDs may reduce diuretic and antihypertensive action of chlorthalidone.
In an application with digitalis drugs may increase the risk of toxic effects of digitalis preparations by hypokalemia caused by the action of chlorthalidone.
While the application of lithium carbonate increased the concentration of lithium in blood plasma and the risk of lithium toxicity.
