VISKAZIDE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for VISKAZIDE (VISKAZIDE).
Viskazide is a combination of pindolol (a non-cardioselective beta-blocker with intrinsic sympathomimetic activity) and hydrochlorothiazide (a thiazide diuretic). Pindolol competitively blocks beta-1 and beta-2 adrenergic receptors, reducing heart rate, myocardial contractility, and blood pressure. Hydrochlorothiazide inhibits the Na+/Cl- symporter in the distal convoluted tubule, decreasing sodium and water reabsorption, leading to reduced plasma volume and blood pressure.
| Metabolism | Pindolol undergoes hepatic metabolism primarily via hydroxylation and conjugation; approximately 60-65% is metabolized, with 35-40% excreted unchanged in urine. Hydrochlorothiazide is not metabolized and is excreted unchanged in urine. |
| Excretion | Renal elimination (approximately 70% unchanged), with the remainder as inactive metabolites; biliary/fecal excretion is minor (<10%). |
| Half-life | Terminal elimination half-life is 10-12 hours for the hydrochlorothiazide component and 4-6 hours for pindolol; clinical context: steady-state achieved in 2-3 days for pindolol and 3-5 days for hydrochlorothiazide. |
| Protein binding | Pindolol: 40-50% bound to albumin; Hydrochlorothiazide: 40-68% bound to albumin. |
| Volume of Distribution | Pindolol: 1.2-2.0 L/kg indicating extensive tissue distribution; Hydrochlorothiazide: 3-4 L/kg suggesting wide distribution. |
| Bioavailability | Oral bioavailability: Pindolol 80-95%, Hydrochlorothiazide 65-75%. |
| Onset of Action | Oral: Antihypertensive effect begins within 1-2 hours; peak effect occurs at 3-6 hours. |
| Duration of Action | Duration of antihypertensive effect is approximately 24 hours; clinical notes: once-daily dosing is sufficient due to the long-acting combination. |
Oral: 1 tablet (pindolol 10 mg / hydrochlorothiazide 25 mg) once daily; may increase to 2 tablets once daily if needed.
| Dosage form | TABLET |
| Renal impairment | For GFR 30-60 mL/min: use with caution, monitor BP. For GFR <30 mL/min: contraindicated (thiazide ineffective). |
| Liver impairment | Child-Pugh A: no dose adjustment. Child-Pugh B: reduce dose (e.g., start at pindolol 5 mg + HCTZ 12.5 mg) and titrate slowly. Child-Pugh C: contraindicated. |
| Pediatric use | Not recommended in pediatric patients (safety and efficacy not established). |
| Geriatric use | Start with lower dose (e.g., pindolol 5 mg + HCTZ 12.5 mg) due to increased sensitivity; titrate slowly. Monitor electrolytes and renal function. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for VISKAZIDE (VISKAZIDE).
| Breastfeeding | Pindolol and hydrochlorothiazide are excreted in breast milk. M/P ratio for pindolol ~1.0; hydrochlorothiazide ~0.2. Monitor infant for bradycardia, hypotension, and diuretic effects. Consider benefits vs risks. |
| Teratogenic Risk | FDA Pregnancy Category C. First trimester: Limited human data; animal studies show embryotoxicity (hydrochlorothiazide) and no teratogenicity (pindolol). Second/third trimesters: Hydrochlorothiazide may cause fetal jaundice, thrombocytopenia, and electrolyte disturbances; pindolol may cause fetal bradycardia and hypoglycemia. Avoid use in pregnancy unless benefit outweighs risk. |
■ FDA Black Box Warning
Exacerbation of ischemic heart disease following abrupt discontinuation: Beta-blocker withdrawal may precipitate angina, myocardial infarction, or ventricular arrhythmias in patients with coronary artery disease. Therapy should be tapered gradually over 1-2 weeks.
| Serious Effects |
["Hypersensitivity to pindolol, hydrochlorothiazide, or sulfonamide-derived drugs","Bronchial asthma or COPD","Sinus bradycardia, heart block greater than first degree","Cardiogenic shock","Overt heart failure","Anuria or severe renal impairment (creatinine clearance <30 mL/min)"]
| Precautions | ["Cardiac failure: Avoid in patients with overt heart failure; use cautiously in compensated heart failure.","Bronchospasm: Contraindicated in bronchial asthma or COPD due to beta-blockade.","Peripheral vascular disease: May exacerbate symptoms due to beta-2 blockade.","Diabetes: Beta-blockers may mask hypoglycemic symptoms (e.g., tachycardia) and potentiate insulin-induced hypoglycemia.","Thyrotoxicosis: Beta-blockade may mask signs of hyperthyroidism (e.g., tachycardia); abrupt withdrawal may precipitate thyroid storm.","Renal impairment: Hydrochlorothiazide may worsen renal function; monitor BUN and creatinine.","Electrolyte disturbances: Hypokalemia, hyponatremia, hypomagnesemia, and hypochloremic alkalosis may occur."] |
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| Fetal Monitoring | Maternal: Blood pressure, heart rate, serum electrolytes, renal function, and blood glucose. Fetal: Heart rate, growth ultrasound, and amniotic fluid volume if used in second/third trimesters. |
| Fertility Effects | No known significant effect on fertility. Hydrochlorothiazide may cause reversible sexual dysfunction in males. Pindolol may rarely cause erectile dysfunction. |