SOLIMAX-Q TABLET 5MG

Indications

• Overactive bladder
• Urinary incontinence
• Urinary urgency
• Urinary frequency

Dosage

Children: Safety and efficacy have not been established in children; refer to BNF for Children for specific dosing recommendations.

Adults: The usual adult dose is 5 mg once daily, which may be increased to 10 mg once daily based on individual patient response and tolerability.

Mechanism of action

Solifenacin competitively inhibits muscarinic receptors, with a high affinity for M3, M1, and M2 receptors. By antagonizing the M3 receptor, it prevents detrusor muscle contraction, while antagonism of the M2 receptor may inhibit contraction of bladder smooth muscle, thereby alleviating symptoms of overactive bladder.

Pharmacodynamics

The drug effectively reduces symptoms associated with overactive bladder by blocking the muscarinic receptors. Its long duration of action allows for once-daily dosing, providing consistent symptom control. However, patients should be monitored for potential adverse reactions such as angioedema and anaphylaxis, which can occur in some individuals.

Pharmacokinetics

Solifenacin is absorbed well following oral administration, with peak plasma concentrations occurring approximately 3 to 8 hours after dosing. It undergoes hepatic metabolism primarily via cytochrome P450 enzymes, leading to various metabolites, some of which may retain pharmacological activity. The elimination half-life is around 45 to 68 hours, supporting its once-daily dosing regimen. Renal and hepatic function may influence the drug's clearance.

Adverse effects

• dry mouth
• constipation
• blurred vision
• urinary retention
• angioedema
• anaphylaxis

Interactions

• clozapine+solifenacin: Unknown (additive effect)
• cobicistat+solifenacin: Unknown (increases exposure)
• idelalisib+solifenacin: Unknown (increases exposure)
• clarithromycin+solifenacin: Unknown (increases exposure)
• mitotane+solifenacin: Unknown (decreases exposure)
• rifampicin+solifenacin: Unknown (decreases exposure)
• antipsychotics, second generation+solifenacin: Unknown (additive effect)

Pregnancy

The safety of solifenacin during pregnancy has not been established. Use only if the potential benefit justifies the potential risk to the fetus.

Breast-feeding

Solifenacin is excreted in breast milk. Caution is advised when administered to nursing women.

Storage

Store in a cool, dry place, away from direct sunlight and moisture. Keep out of reach of children.

Formulations

• tablets

Indications

• Urinary frequency
• Urgency
• Incontinence associated with overactive bladder
• Incontinence associated with neurogenic bladder instability

Dosage

Children: Refer to the BNF for Children for appropriate dosing information, as specific pediatric dosing is not provided.

Adults: 15 mg once daily, increased if necessary to a maximum of 30 mg once daily for immediate-release formulations. For modified-release capsules, the usual dose is 30 mg once daily.

Mechanism of action

Solifenacin succinate selectively inhibits the M3 subtype of muscarinic acetylcholine receptors, which are primarily responsible for bladder contraction. By blocking these receptors, solifenacin reduces detrusor muscle overactivity, leading to decreased urinary frequency and urgency.

Pharmacodynamics

The pharmacodynamic effects of solifenacin include a reduction in bladder contractions, increased bladder capacity, and diminished urgency to void. Its antimuscarinic properties help alleviate the symptoms associated with overactive bladder, providing symptomatic relief in patients with urinary incontinence.

Pharmacokinetics

Solifenacin is well absorbed after oral administration, with peak plasma concentrations occurring approximately 3 to 8 hours post-dose. It has a bioavailability of around 90% and is extensively metabolized in the liver via CYP3A4. The elimination half-life is approximately 45 hours, allowing for once-daily dosing. Renal impairment can affect its clearance, necessitating dose adjustments in patients with reduced creatinine clearance.

Contra-indications

• Severe hepatic impairment
• Moderate to severe renal impairment
• Hypersensitivity to solifenacin or any of its excipients

Adverse effects

• Abdominal pain
• Fatigue
• Altered taste
• Tremor
• Restlessness
• Hallucination
• Anaphylactic reaction
• Delirium
• Dysphonia
• Muscle weakness
• QT interval prolongation

Interactions

• Anticholinergic agents may enhance effects
• CYP3A4 inhibitors (e.g., ketoconazole) may increase solifenacin levels
• CYP3A4 inducers (e.g., rifampicin) may decrease solifenacin levels
• Concurrent use of medications that prolong QT interval should be approached with caution

Precautions

• Caution in patients with gastrointestinal disorders
• Caution in elderly patients due to increased sensitivity
• Caution in patients with a history of glaucoma
• Caution in patients with urinary retention

Pregnancy

Manufacturer advises caution due to lack of information available on safety in pregnancy.

Breast-feeding

Manufacturer advises avoiding use as solifenacin is present in milk in animal studies.

Storage

Store at room temperature, away from moisture and heat. Keep out of reach of children.

Formulations

• Oral solution: Solifenacin succinate 1 mg per 1 ml
• Modified-release capsule: Solifenacin succinate 5 mg
• Modified-release capsule: Solifenacin succinate 30 mg

Mechanism of action

Solifenacin 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. Solifenacin'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.

Pharmacodynamics

Solifenacin antagonizes the M2 and M3 muscarinic receptors in the bladder to treat an overactive bladder. It has a long duration of action as it is usually taken once daily. Patients taking solifenacin should be aware of the risks of angioedema and anaphylaxis.