In the urinary system, urine is produced in the kidneys and flows through the ureters to the bladder, where it is held until you urinate. The normal functions of the bladder are controlled by muscle activity and nerve signals. An overactive bladder is a condition that occurs when the muscles of the bladder contract involuntarily, creating the urge to urinate frequently (defined by doctors at the Mayo Clinic to be more than 8 times in 24 hours) and often resulting in incontinence, the leakage of urine. Although you can make changes that will help to alleviate the symptoms of an overactive bladder, physicians often prescribe medications to relax the bladder to enhance the relief.
Anticholinergics
Anticholinergic medications, including oxybutynin, tolterodine, darifenacin, trospium and solifenacin, relieve the symptoms of an overactive bladder by relaxing the bladder's muscles. These medications work by blocking acetylcholine, a chemical that is responsible for transmitting signals between nerves. Once bound to the receptor on a muscle cell, acetylcholine activates the muscle, triggering it to contract. By blocking this chemical, anticholinergics decrease muscle contractions.
Anticholinergic medications are often referred to as antispasmodic drugs because they relax the bladder muscle causing it to cease spasms (muscle contractions). The most common side effects of these medications include dry mouth, dry eyes and constipation.
Tricyclic Antidepressants
Tricyclic antidepressants are a group of medications that are most commonly prescribed to treat depression. These medications, including amitriptyline, nortriptyline, doxepin and imipramine, increase the levels of certain neurotransmitters (chemicals that help carry signals between nerves and muscles). By affecting the chemical messengers such as noradrenaline and serotonin, these medications can help to relax the bladder muscle, reducing the contractions causing the overactive bladder symptoms. The National Institutes of Health reports that the most common side effects of tricyclic antidepressants include blurred vision, dizziness, dry mouth, fatigue, insomnia and nausea.
Antidiuretics
The antidiuretic medication desmopressin is a synthetic (man-made) form of the natural hormone vasopressin. Vasopressin is naturally produced in the body and is responsible for telling the kidneys to produce less urine. Desmopressin performs the same function, directing the kidneys to produce less urine, which can help to relieve an overactive bladder. The National Kidney and Urological Diseases Information Clearinghouse reports that the most common side effects of this antidiuretic drug include headache, nausea, reddening of the skin, stomach cramps and a runny or stuffy nose.
Botulinum Toxin
Botulinum toxin is a protein produced by the bacteria Clostridium botulinum. This protein is responsible for causing botulism, a potentially dangerous illness. When injected in small doses, however, botulinum toxin can paralyze the muscles of the bladder. This stops the involuntary contractions of the bladder muscle,alleviating the continual feeling of needing to urinate. The doctors at the Mayo Clinic report that although the Food and Drug Administration has not approved using botulinum toxin for this indication, it is an effective temporary treatment.
