Gatosol

Uses

Symptomatic treatment of urge incontinence and/or increased urinary frequency and urgency as may occur in patients with overactive bladder syndrome.

Gatosol is also used to associated treatment for these conditions: Benign Prostatic Hyperplasia (BPH), Urinary Bladder, Overactive

How Gatosol works

Gatosol is a competitive muscarinic receptor antagonist. It has the highest affinity for M3, M1, and M2 muscarinic receptors. 80% of the muscarinic receptors in the bladder are M2, while 20% are M3. Gatosol's antagonism of the M3 receptor prevents contraction of the detrusor muscle, while antagonism of the M2 receptor may prevent contraction of smooth muscle in the bladder.

Dosage

Gatosol dosage

Adults, including the elderly: The recommended dose is Gatosol Succinate 5 mg once daily. If needed, the dose may be increased to Gatosol Succinate 10 mg once daily.

Children and adolescents: Safety and effectiveness in children have not yet been established. Therefore, Gatosol Succinate should not be used in children.

Side Effects

The most common side effects are blurred vision, dry mouth, constipation & heat prostration. Other side effects include dizziness, fatigue, edema, palpitation and skin reactions. Disorientation, hallucination and convulsion may occur.

Toxicity

The LD₅₀ of Gatosol has yet to be determined.

Signs of overdose include severe anticholinergic effects, mental status changes, and decreased consciousness. In case of overdose, treat patients with gastric lavage and supportive measures. Monitor patients with an ECG.

Precaution

Other causes of frequent urination (heart failure or renal disease) should be assessed before treatment with Gatosol. If urinary tract infection is present, an appropriate antibacterial therapy should be started. Gatosol Succinate should be used with caution in patients with clinically significant bladder outflow obstruction at risk of urinary retention, gastrointestinal obstructive disorders, risk of decreased gastrointestinal motility, severe renal impairment (creatinine clearance 30 ml/min), moderate hepatic impairment, concomitant use of a strong CYP3A4 inhibitor, e.g. ketoconazole

Interaction

Concomitant medication with other drugs with anticholinergic properties may result in more pronounced therapeutic effects and side effects. The therapeutic effect of solifenacin may be reduced by concomitant administration of cholinergic receptor agonists. Gatosol can reduce the effect of drugs that stimulate the motility of the gastro-intestinal tract, such as metoclopramide and cisapride. Ketoconazole & other CYP3A4 inhibitors increase the plasma concentration of solifenacin.

Food Interaction

• Take with or without food.

Gatosol Drug Interaction

Moderate: diphenhydramine, mirabegron, budesonide / formoterolMinor: acetaminophen, acetaminophenUnknown: aspirin, ubiquinone, duloxetine, apixaban, omega-3 polyunsaturated fatty acids, pregabalin, metoprolol, metoprolol, levothyroxine, cyanocobalamin, ascorbic acid, ergocalciferol, cholecalciferol, rivaroxaban, cetirizine

Gatosol Disease Interaction

Major: GI motility, kidney impairment, liver impairment, narrow-angle glaucoma, urinary obstructionModerate: CNS, QT prolongation

Volume of Distribution

The volume of distribution of solifenacin is 600L.

Elimination Route

Gatosol is well absorbed in the duodenum, jejunum, and ileum but not the stomach. Absorption occurs via passive diffusion and so no transporters are involved. The mean oral bioavailability of solifenacin is 88%. The T_max of solifenacin is 3-8 hours with a C_ss of 32.3ng/mL for a 5mg oral dose and 62.9ng/mL for a 10mg oral dose.

Half Life

The elimination half life of solifenacin ranges from 33-85 hours.

Clearance

The clearance of solifenacin is 7-14L/h and a renal clearance of 0.67-1.51L/h.

Elimination Route

69.2±7.8% of a radiolabelled dose is recovered in the urine, 22.5±3.3% was recovered in feces, and 0.4±7.8% was recovered in exhaled air. 18% of solifenacin is eliminated as the N-oxide metabolite, 9% is eliminated as the 4R-hydroxy N-oxide metabolite, and 8% is eliminated as the 4R-hydroxy metabolite.

Pregnancy & Breastfeeding use

Use in pregnancy: There are no adequate data from the use of solifenacin succinate in pregnant women. Caution should be exercised while prescribing solifenacin to pregnant women.

Use in lactating mother: No data concerning the excretion of solifenacin into breast milk are available. The use of Gatosol is avoided in lactating mother.

Contraindication

Gatosol is contraindicated in patients with hypersensitivity to solifenacin or to any of the excipients. It is also contraindicated in myasthenia gravis, urinary retention, uncontrolled narrow angle glaucoma, severe gastro-intestinal condition (including toxic megacolon), patients undergoing haemodialysis, patients with severe hepatic impairment, patients with severe renal impairment or moderate hepatic impairment and on treatment with a strong CYP3A4 inhibitor, e.g. ketoconazole.

Special Warning

Patients with renal impairment: No dosage adjustment is necessary for patients with mild to moderate renal impairment (creatinine clearance > 30 ml/min). Patients with severe renal impairment (creatinine clearance 30 ml/min) should be treated with caution and receive no more than 5 mg Gatosol SuccinateTablet once daily.

Patients with hepatic impairment: No dosage adjustment is necessary for patients with mild hepatic impairment. Patients with moderate hepatic impairment should be treated with caution and receive no more than 5 mg Gatosol SuccinateTablet once daily.

Patients taking CYP3A4 inhibitors concomitantly: The maximum dose of Gatosol Succinateshould be limited to 5 mg when treated simultaneously with ketoconazole or other potent CYP3A4 inhibitors e.g. ritonavir, nelfinavir or itraconazole.

Use in children: Safety and efficacy of solifenacin in children have not been established.

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