Solifenacin is a member of the urinary antagonist or antispasmodic medication class, which is mostly used to treat symptoms related to overactive bladder. The condition known as overactive bladder causes the muscles of the bladder to contract uncontrollably, which leads to frequent urination, an urgent need to urinate, and trouble controlling one's urination. In children two years of age and older, it is also used to treat neurogenic detrusors or hyperactive detrusors. It lowers the activity of the overactive bladder by relaxing the muscles surrounding the bladder. When a patient has an overactive bladder, their muscles contract before the bladder fully expands, which results in frequent desires to urinate. Solifenacin allows control over urine by preventing these abrupt contractions of the bladder's muscular contractions. It increases the volume and amount of pee the bladder can contain. In 2004, the FDA authorized it.
BRAND NAMES:
Vesicare: It contains the active ingredient of solifenacin. It is available in the form of tablets and suspensions used to treat overactive bladder.
MECHANISM OF ACTION:
A competitive muscarinic receptor antagonist is solifenacin. When it comes to muscarinic receptors, M3, M1, and M2 have the highest affinity. In the bladder, 20% of muscarinic receptors are M3 and 80% are M2 receptors. The detrus muscle cannot contract when solifenacin antagonism of the M3 receptor occurs, whereas the smooth muscle in the bladder may not contract when solifenacin antagonism of the M2 receptor occurs.
PHARMACOKINETICS:
ABSORPTION: Solifenacin is easily absorbed in the duodenum, jejunum, and ileum, but not in the stomach. Absorption occurs via passive diffusion; hence, no transporters are involved. The average oral bioavailability of solifenacin is 88%, with a Tmax of 3–8 hours.
DISTRIBUTION: Solifenacin is distributed in a 600L volume.
METABOLISM: Solifenacin is N-oxidised at the quinuclidin ring by cytochrome P450, albeit the particular enzymes are unknown in the literature. CYP3A4, CYP1A1, and CVYP2D6 all hydroxylate the tetrahydroisoquinolone ring 4R. A 4R-hydroxyl N-oxide metabolite is also produced by CYP3A4. Finally, solifenacin can undergo direct glucuronidation. Only solifenacin and its 4R-hydroxy metabolite are pharmacologically active.
EXCRETION: Solifenacin is excreted through urine and feces
PHARMACODYNAMICS:
To treat an overactive bladder, solifenacin works by antagonizing the M2 and M3 muscarinic receptors. It has a long duration of action because it is typically administered once daily. Patients who use solifenacin should be informed of the dangers of angioedema and anaphylaxis.
DOSAGE AND ADMINISTRATION:
Solifenacin is available in the form of tablets and oral suspensions. Solifenacin tablets are normally used once per day, with or without food. Solifenacin suspension is typically taken once per day. To help you remember to take solifenacin, take it about the same time each day.
Solifencin is available in tablets with dosages of 5 mg and 10 mg.
DRUG INTERACTIONS:
Drug interaction of solifenacin may include
- Gastrointestinal agents: metoclopramide and cisapride
- Anti-fungal drugs: ketoconazole and itraconazole
- HIV drugs: ritonavir
- Anti-hypertensives: verapamil and diltiazem
- Antibiotics: rifampicin
- Anti-epileptic drugs: phenytoin and carabamazepine
CONTRAINDICATIONS:
Solifenacin is not recommended for hypersensitivity, stomach retention, uncontrolled narrow-angle glaucoma, or urine retention.
SIDE EFFECTS:
Side effects of solifenacin may include
• Vomiting
• Constipation
• Dry mouth
• Stomach pain
• Blurred vision
• Stomach upset
• Dry skin
Serious side effects may include
• Back pain
• Constipation
• Cloudy or bloody urine
• Hoarseness
• Itching
• Rash
• Confusion
• Headache
• Hallucination
• Extreme tiredness
• Swelling of the face
OVERDOSE:
Symptoms of overdose may include
• Blurred vision
• Dry eyes
• Flushing
• Dry mouth
• Fever
• Fast heartbeat
• Difficulty walking
• Dry skin
• Difficulty walking
TOXICITY:
Severe anticholinergic effects, changes in metal status, and lowered consciousness are indicators of an overdose. Patients who have overdosed should be treated with supportive care and gastric lavage. Observe patients using an ECG.
