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. |
| Molecular Weight | 248.33 |
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 | Avoid; risk of fetal bradycardia, growth restriction, and teratogenic effects (animal studies). Use only if clearly needed. |
| 2nd trimester | Avoid; may cause fetal bradycardia, hypoglycemia, and low birth weight. Monitor fetal growth if used. |
| 3rd trimester | Avoid; may cause neonatal bradycardia, hypotension, hypoglycemia, and respiratory depression at birth. |
Clinical note
Comprehensive clinical and safety monograph for VISKAZIDE (VISKAZIDE).
| Placental transfer | Both pindolol and hydrochlorothiazide cross the placenta. Pindolol transfer is significant; hydrochlorothiazide transfer is limited but present. |
| Breastfeeding | Pindolol and hydrochlorothiazide are excreted in breast milk. Pindolol may cause infant bradycardia; hydrochlorothiazide may decrease milk production. Use with caution, monitor infant for effects. |
■ 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 drugsBronchial asthma or COPD with bronchospasmSinus bradycardia less than 45 bpmSecond- or third-degree heart blockCardiogenic shockAnuria (due to hydrochlorothiazide component)Uncompensated heart failure
| 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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| Lactation Rating | L3 (Moderately Safe) - potential for serious adverse reactions in nursing infant; benefit should outweigh risk. |
| 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. |
| 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. |
| Food/Dietary | Avoid alcohol which may enhance hypotensive effects. Limit sodium intake to prevent fluid retention and counteract thiazide effect. Avoid excessive potassium intake (e.g., bananas, orange juice, salt substitutes) if using potassium-sparing adjuncts. Grapefruit juice may increase pindolol levels; avoid concurrent consumption. |
| Clinical Pearls | VISKAZIDE contains pindolol (a nonselective beta-blocker with intrinsic sympathomimetic activity) and a thiazide diuretic. Titrate slowly in elderly; monitor for bradycardia, heart block, and electrolyte disturbances. Use with caution in asthma, COPD, and peripheral vascular disease. The ISA minimizes resting bradycardia but does not protect against bronchospasm. Check serum potassium, sodium, and uric acid periodically. |
| Patient Advice | Take exactly as prescribed; do not stop abruptly due to risk of rebound hypertension or angina. · Weigh yourself daily and report rapid weight gain or swelling to your doctor. · Avoid activities requiring alertness until you know how this medication affects you. · Rise slowly from sitting or lying to prevent dizziness. · Report slow heartbeat, shortness of breath, or cold hands and feet. · Take with food or milk if stomach upset occurs. · Avoid potassium supplements or salt substitutes without consulting your doctor. |