They are no more effective than behavioral methods; however, they are associated with side effects, particularly in older people. Some non-invasive electrical stimulation methods appear effective while they are in use. Injections of botulinum toxin into the bladder is another option. Urinary catheters or surgery are generally not recommended. A diary to track problems can help determine whether treatments are working.Overactive bladder is estimated to occur in 7-27% of men and 9-43% of women. It becomes more common with age. Some studies suggest that the condition is more common in women, especially when associated with loss of bladder control. Economic costs of overactive bladder were estimated in the United States at US$12.6 billion and 4.2 billion Euro in 2000. Signs and symptoms
Overactive bladder is characterized by a group of four symptoms: urgency, urinary frequency, nocturia, and urge incontinence. Urge incontinence is not present in the "dry" classification.Urgency is considered the hallmark symptom of OAB, but there are no clear criteria for what constitutes urgency and studies often use other criteria. Urgency is currently defined by the International Continence Society (ICS), as of 2002, as "Sudden, compelling desire to pass urine that is difficult to defer." The previous definition was "Strong desire to void accompanied by fear of leakage or pain." The definition does not address the immediacy of the urge to void and has been criticized as subjective.Urinary frequency is considered abnormal if the person urinates more than eight times in a day.
Variations within the CYP2C9 gene that result in decreased enzymatic activity have been associated with increased phenytoin concentrations, as well as reports of drug toxicities due to these increased concentrations. The U.S. Food and Drug Administration (FDA) notes on the phenytoin drug label that since strong evidence exists linking HLA-B*1502 with the risk of developing SJS or TEN in patients taking carbamazepine, consideration should be given to avoiding phenytoin as an alternative to carbamazepine in patients carrying this allele. Immune system
Phenytoin has been known to cause drug-induced lupus.Phenytoin is also associated with induction of reversible IgA deficiency. Psychological
Phenytoin may increase risk of suicidal thoughts or behavior. People on phenytoin should be monitored for any changes in mood, the development or worsening depression, and/or any thoughts or behavior of suicide. Some case reports of acute phenytoin psychosis were already described. Bones
Chronic phenytoin use has been associated with decreased bone density and increased bone fractures. Phenytoin induces metabolizing enzymes in the liver. This leads to increased metabolism of vitamin D, thus decreased vitamin D levels. Vitamin D deficiency, as well as low calcium and phosphate in the blood cause decreased bone mineral density. Interactions
Phenytoin is an inducer of the CYP3A4 and CYP2C9 families of the P450 enzyme responsible for the livers degradation of various drugs.A 1981 study by the National Institutes of Health showed that antacids administered concomitantly with phenytoin "altered not only the extent of absorption but also appeared to alter the rate of absorption.