DARANIDE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for DARANIDE (DARANIDE).
Carbonic anhydrase inhibitor. Inhibits carbonic anhydrase in the proximal renal tubule, reducing bicarbonate reabsorption and causing alkaline diuresis.
| Metabolism | Not extensively metabolized; excreted unchanged in urine. |
| Excretion | Renal: unchanged drug (approximately 50% of absorbed dose) and metabolites. Biliary/fecal: minimal. |
| Half-life | Terminal elimination half-life: 2.5-3.5 hours (prolonged in renal impairment). Clinical context: Short half-life necessitates multiple daily dosing for sustained diuretic effect. |
| Protein binding | ~90% bound, primarily to albumin. |
| Volume of Distribution | 0.2-0.3 L/kg. Clinical meaning: Confined primarily to extracellular fluid; low Vd indicates minimal tissue distribution. |
| Bioavailability | Oral: 75-85% (tablet). |
| Onset of Action | Oral: 30-60 minutes. Intravenous: 5-15 minutes. |
| Duration of Action | Oral: 6-12 hours (dose-dependent). Intravenous: 2-4 hours. Note: Longer duration may occur in renal impairment. |
| Molecular Weight | 305.15 |
50 mg orally once or twice daily; maximum 100 mg/day.
| Dosage form | TABLET |
| Renal impairment | GFR 10-50 mL/min: 50 mg every 12-24 hours; GFR <10 mL/min: 50 mg every 24-48 hours; not effective if GFR <10 mL/min. |
| Liver impairment | Child-Pugh Class A: no adjustment; Class B: reduce dose by 50%; Class C: use not recommended. |
| Pediatric use | Not established; use not recommended in children. |
| Geriatric use | Start at 25 mg once daily; monitor renal function and electrolyte balance due to increased risk of adverse effects. |
| 1st trimester | Avoid due to risk of teratogenicity; animal studies show potential for fetal harm. |
| 2nd trimester | Avoid unless benefit clearly outweighs risk; may cause metabolic acidosis in fetus. |
| 3rd trimester | Avoid near term due to risk of kernicterus in neonates; may cause electrolyte disturbances. |
Clinical note
Comprehensive clinical and safety monograph for DARANIDE (DARANIDE).
| Placental transfer | Dichlorphenamide crosses the placenta; evidence from animal studies and human data (limited) indicate placental transfer. |
| Breastfeeding | Excreted into breast milk in low concentrations; however, due to potential for serious adverse effects in infants (e.g., metabolic acidosis, electrolyte imbalance), alternative agents are preferred. |
■ FDA Black Box Warning
None.
| Serious Effects |
Hypersensitivity to dichlorphenamide or sulfonamidesSevere hepatic or renal impairmentHypokalemia or hyponatremiaMetabolic acidosisAdrenocortical insufficiency
| Precautions | May cause drowsiness, confusion, or paresthesias, Monitor electrolytes and renal function, Can cause metabolic acidosis, Use caution in patients with hepatic impairment or cirrhosis |
| Food/Dietary | No specific food interactions reported. However, maintain adequate hydration to reduce risk of kidney stones. Avoid excessive salt intake if edema is present. Grapefruit juice is not known to interact. |
| Clinical Pearls |
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| Lactation Rating |
| L4 (Possibly Hazardous) |
| Teratogenic Risk | Pregnancy Category C. First trimester: Possible association with congenital malformations (limited human data; animal studies show fetal toxicity). Second/third trimester: Risk of electrolyte disturbances and acidosis in neonate; avoid use unless benefit outweighs risk. |
| Fetal Monitoring | Monitor maternal electrolytes (Na, K, Cl, HCO3), blood pH (metabolic acidosis), renal function, and hepatic function. Fetal monitoring: ultrasound for growth and amniotic fluid volume (risk of oligohydramnios). |
| Fertility Effects | No adequate studies; potential for reversible effects on reproductive function (inhibition of carbonic anhydrase may affect sperm motility and oocyte maturation). |
| DARANIDE (dichlorphenamide) is a carbonic anhydrase inhibitor used for chronic open-angle glaucoma and secondary glaucoma. Monitor for metabolic acidosis, especially in patients with renal impairment. Can cause hypokalemia; check serum potassium periodically. Avoid concurrent use with high-dose salicylates due to risk of metabolic acidosis and salicylate toxicity. May cause drowsiness or confusion; caution in elderly. Not a first-line agent; reserved for patients intolerant or unresponsive to other therapies. |
| Patient Advice | Take exactly as prescribed, usually 3-4 times daily with food to reduce GI upset. · May cause tingling or numbness in fingers, toes, or mouth; this is common and usually harmless. · Drink plenty of fluids to prevent kidney stones; report painful urination or blood in urine. · Avoid aspirin or high-dose salicylates; check with doctor before taking any OTC pain relievers. · Regular eye exams and blood tests (potassium, bicarbonate) are necessary. · May cause drowsiness or dizziness; avoid driving until you know how it affects you. · Tell your doctor if you have kidney disease, liver disease, or electrolyte imbalance. · Notify your doctor if you experience weakness, weight loss, confusion, or rapid breathing. |