Drug Interaction Report

Valproic acid has a moderate potential interaction with Bleeding Disorder.

The use of valproate derivatives may be associated with dose-related thrombocytopenia, the incidence of which is generally low but has been reported at up to 27% in one study using high dosages (approximately 50 mg/kg/day of valproic acid). In that study, platelet counts returned to normal in all patients, some despite continued treatment. Valproate may also inhibit the secondary phase of platelet aggregation, although this effect is unlikely to be of clinical significance except during the concomitant use of other drugs that affect coagulation. However, altered bleeding time, ecchymosis, petechiae, bruising, hematoma formation, epistaxis, and frank hemorrhage have been reported rarely. Hypofibrinogenemia has also been observed. Therapy with valproate products, particularly at high dosages, should be administered cautiously in patients with significant active bleeding or a hemorrhagic diathesis, including hemostatic and/or coagulation defects associated with hemophilia, vitamin K deficiency, hypoprothrombinemia, thrombocytopenia, thrombocytopathy, or severe hepatic impairment. The manufacturers recommend platelet counts and coagulation tests prior to initiating therapy and at periodic intervals thereafter, as well as before planned surgery. The dosage should be reduced or the drug withdrawn if clinical evidence of hemorrhage, bruising, or a disorder of hemostasis or coagulation occurs.

Valproic acid has a major potential interaction with Brain Anomalies incl Congenital.

The use of valproate derivatives is contraindicated in patients with hepatic disease or significant hepatic dysfunction. Serious and potentially fatal hepatotoxicity has been reported in patients treated with these agents. The risk appears to be greatest in children less than 2 years of age--particularly those on multiple anticonvulsants and those with congenital metabolic disorders, severe seizure disorders accompanied by intellectual disability, or organic brain disease--and decreases considerably in progressively older patient groups. Therapy with valproate products should be administered with extreme caution and as a sole agent in patients with risk factors for valproate-related hepatotoxicity. In reported cases, the onset has generally been within the first 6 months of treatment and may be preceded by nonspecific symptoms such as malaise, weakness, lethargy, facial edema, anorexia, nausea, vomiting, and a loss of seizure control. Patients should be monitored closely for appearance of these symptoms, and therapy withdrawn immediately if significant hepatic dysfunction occurs. Liver function tests should be performed prior to initiating therapy and at frequent intervals thereafter, especially during the first 6 months. However, clinicians should bear in mind that transient, dose-related, asymptomatic elevations in serum transaminase, amylase and ammonia levels may commonly occur and often return to normal with or without dosage adjustment.

Tolterodine has a moderate potential interaction with Central Nervous System Disorders.

Tolterodine is associated with anticholinergic central nervous system (CNS) effects. If a patient experiences anticholinergic CNS effects, dose reduction or drug discontinuation should be considered. Tolterodine should be used with caution in patients with Parkinson's disease and in patients with preexisting dementia treated with cholinesterase inhibitors due to the risk of aggravation of symptoms.

Valproic acid has a moderate potential interaction with Coagulation Defects and Disorders.

The use of valproate derivatives may be associated with dose-related thrombocytopenia, the incidence of which is generally low but has been reported at up to 27% in one study using high dosages (approximately 50 mg/kg/day of valproic acid). In that study, platelet counts returned to normal in all patients, some despite continued treatment. Valproate may also inhibit the secondary phase of platelet aggregation, although this effect is unlikely to be of clinical significance except during the concomitant use of other drugs that affect coagulation. However, altered bleeding time, ecchymosis, petechiae, bruising, hematoma formation, epistaxis, and frank hemorrhage have been reported rarely. Hypofibrinogenemia has also been observed. Therapy with valproate products, particularly at high dosages, should be administered cautiously in patients with significant active bleeding or a hemorrhagic diathesis, including hemostatic and/or coagulation defects associated with hemophilia, vitamin K deficiency, hypoprothrombinemia, thrombocytopenia, thrombocytopathy, or severe hepatic impairment. The manufacturers recommend platelet counts and coagulation tests prior to initiating therapy and at periodic intervals thereafter, as well as before planned surgery. The dosage should be reduced or the drug withdrawn if clinical evidence of hemorrhage, bruising, or a disorder of hemostasis or coagulation occurs.

Tolterodine has a moderate potential interaction with Dementia.

Tolterodine is associated with anticholinergic central nervous system (CNS) effects. If a patient experiences anticholinergic CNS effects, dose reduction or drug discontinuation should be considered. Tolterodine should be used with caution in patients with Parkinson's disease and in patients with preexisting dementia treated with cholinesterase inhibitors due to the risk of aggravation of symptoms.

Valproic acid has a major potential interaction with Depression.

Antiepileptic drugs can increase depression and suicidal thoughts or behaviors in patients receiving these drugs for any indication. Patients should be monitored for the emergence or worsening of depression, suicidal thoughts and unusual changes in mood or behavior. Caregivers and family should be alert for the emergence or worsening of symptoms. Behaviors of concern should be reported immediately to the healthcare providers.

Valproic acid has a moderate potential interaction with Depression.

Antiepileptic drugs (AEDs) have been associated with an increased risk of suicidal thoughts or behavior in patients taking these drugs for any indication. Pooled analyses of 199 placebo-controlled clinical studies involving the use of 11 different AEDs showed that patients receiving AEDs had approximately twice the risk of suicidal thinking or behavior compared to patients receiving placebo. AEDs should be administered cautiously in patients with depression or other psychiatric disorders; phentermine-topiramate should be avoided in patients with history of suicidal attempts or active suicidal ideation. The risk of suicidal thoughts and behavior should be carefully assessed against the risk of untreated illness, bearing in mind that epilepsy and many other conditions for which AEDs are prescribed are themselves associated with morbidity and mortality and an increased risk of suicidal thoughts and behavior. Patients, caregivers, and families should be alert to the emergence or worsening of signs and symptoms of depression, any unusual changes in mood or behavior, or the emergence of suicidal thoughts or behavior. If patients have symptoms of suicidal ideation or behavior, a dosage reduction or treatment discontinuation should be considered.

Valproic acid has a moderate potential interaction with Diabetes Mellitus.

Valproate is partially eliminated in the urine as a ketone-containing metabolite, which may lead to a false interpretation of the urine ketone test. Clinicians should be cognizant of this interaction when prescribing or administering valproate products to patients with diabetes.

Tolterodine has a major potential interaction with Gastrointestinal Obstruction.

The use of tolterodine is contraindicated in patients with GI obstruction, ileus, or obstructive uropathy. Tolterodine exerts anticholinergic activity by competitive antagonism of muscarinic receptors.

Tolterodine has a major potential interaction with Glaucoma/Intraocular Hypertension.

The use of tolterodine is contraindicated in patients with uncontrolled angle-closure (narrow angle) glaucoma. Tolterodine exerts anticholinergic activity and can result in increased intraocular pressure and loss of accommodation.

Valproic acid has a moderate potential interaction with HIV-1 Infection.

Some in vitro studies suggest that valproate stimulates the replication of the HIV and CMV viruses under certain experimental conditions. The clinical consequences are unknown, and the relevance of these findings is uncertain for patients receiving maximally suppressive antiretroviral therapy. However, this should be borne in mind when interpreting the results from regular monitoring of the viral load in HIV infected patients receiving valproate or when following CMV infected patients clinically.

Valproic acid has a major potential interaction with Intellectual Disability.

The use of valproate derivatives is contraindicated in patients with hepatic disease or significant hepatic dysfunction. Serious and potentially fatal hepatotoxicity has been reported in patients treated with these agents. The risk appears to be greatest in children less than 2 years of age--particularly those on multiple anticonvulsants and those with congenital metabolic disorders, severe seizure disorders accompanied by intellectual disability, or organic brain disease--and decreases considerably in progressively older patient groups. Therapy with valproate products should be administered with extreme caution and as a sole agent in patients with risk factors for valproate-related hepatotoxicity. In reported cases, the onset has generally been within the first 6 months of treatment and may be preceded by nonspecific symptoms such as malaise, weakness, lethargy, facial edema, anorexia, nausea, vomiting, and a loss of seizure control. Patients should be monitored closely for appearance of these symptoms, and therapy withdrawn immediately if significant hepatic dysfunction occurs. Liver function tests should be performed prior to initiating therapy and at frequent intervals thereafter, especially during the first 6 months. However, clinicians should bear in mind that transient, dose-related, asymptomatic elevations in serum transaminase, amylase and ammonia levels may commonly occur and often return to normal with or without dosage adjustment.

Valproic acid has a major potential interaction with Intellectual Disability.

Valproic acid and derivative products are contraindicated in patients with known urea cycle disorders (UCD), as hyperammonemic encephalopathy, sometimes fatal, has been reported on these patients following the initiation of treatment. Prior to the initiation of therapy, the evaluation for UCD should be considered in patients with history of unexplained encephalopathy or comma, encephalopathy associated with a protein load, pregnancy- related or postpartum encephalopathy, unexplained intellectual disability, or history of elevated plasma ammonia or glutamine. Also, those with family history of UCD or family history of unexplained infant deaths. Patients who develop symptoms of hyperammonemic encephalopathy while receiving valproate therapy should receive prompt treatment including treatment discontinuation and be evaluated for underlying urea cycle disorders.

Valproic acid has a major potential interaction with Liver Disease.

The use of valproate derivatives is contraindicated in patients with hepatic disease or significant hepatic dysfunction. Serious and potentially fatal hepatotoxicity has been reported in patients treated with these agents. The risk appears to be greatest in children less than 2 years of age--particularly those on multiple anticonvulsants and those with congenital metabolic disorders, severe seizure disorders accompanied by intellectual disability, or organic brain disease--and decreases considerably in progressively older patient groups. Therapy with valproate products should be administered with extreme caution and as a sole agent in patients with risk factors for valproate-related hepatotoxicity. In reported cases, the onset has generally been within the first 6 months of treatment and may be preceded by nonspecific symptoms such as malaise, weakness, lethargy, facial edema, anorexia, nausea, vomiting, and a loss of seizure control. Patients should be monitored closely for appearance of these symptoms, and therapy withdrawn immediately if significant hepatic dysfunction occurs. Liver function tests should be performed prior to initiating therapy and at frequent intervals thereafter, especially during the first 6 months. However, clinicians should bear in mind that transient, dose-related, asymptomatic elevations in serum transaminase, amylase and ammonia levels may commonly occur and often return to normal with or without dosage adjustment.

Tolterodine has a moderate potential interaction with Liver Disease.

Tolterodine undergoes biotransformation in the liver of extensive metabolizers to an active metabolite. Poor metabolizers have a greater concentration of active parent and less active metabolite, however the net activity of tolterodine is expected to be the same. The pharmacokinetic disposition of tolterodine can be significantly altered in patients with hepatic dysfunction. Therapy with tolterodine should be administered cautiously in patients with severe hepatic impairment and dosage should be reduced to no greater than 1 mg twice daily.

Tolterodine has a moderate potential interaction with Long QT Syndrome.

Tolterodine has been associated with QT prolongation. The effect on QT interval correlates with plasma concentration of tolterodine. Caution is recommended when prescribing this agent to patients with a known history of QT prolongation or to patients who are taking Class IA (e.g., quinidine, procainamide) or Class III (e.g., amiodarone, sotalol) antiarrhythmic medications.

Valproic acid has a major potential interaction with Metabolic Disorders.

Valproic acid and derivative products are contraindicated in patients with known urea cycle disorders (UCD), as hyperammonemic encephalopathy, sometimes fatal, has been reported on these patients following the initiation of treatment. Prior to the initiation of therapy, the evaluation for UCD should be considered in patients with history of unexplained encephalopathy or comma, encephalopathy associated with a protein load, pregnancy- related or postpartum encephalopathy, unexplained intellectual disability, or history of elevated plasma ammonia or glutamine. Also, those with family history of UCD or family history of unexplained infant deaths. Patients who develop symptoms of hyperammonemic encephalopathy while receiving valproate therapy should receive prompt treatment including treatment discontinuation and be evaluated for underlying urea cycle disorders.

Valproic acid has a major potential interaction with Metabolic Disorders.

The use of valproate derivatives is contraindicated in patients with hepatic disease or significant hepatic dysfunction. Serious and potentially fatal hepatotoxicity has been reported in patients treated with these agents. The risk appears to be greatest in children less than 2 years of age--particularly those on multiple anticonvulsants and those with congenital metabolic disorders, severe seizure disorders accompanied by intellectual disability, or organic brain disease--and decreases considerably in progressively older patient groups. Therapy with valproate products should be administered with extreme caution and as a sole agent in patients with risk factors for valproate-related hepatotoxicity. In reported cases, the onset has generally been within the first 6 months of treatment and may be preceded by nonspecific symptoms such as malaise, weakness, lethargy, facial edema, anorexia, nausea, vomiting, and a loss of seizure control. Patients should be monitored closely for appearance of these symptoms, and therapy withdrawn immediately if significant hepatic dysfunction occurs. Liver function tests should be performed prior to initiating therapy and at frequent intervals thereafter, especially during the first 6 months. However, clinicians should bear in mind that transient, dose-related, asymptomatic elevations in serum transaminase, amylase and ammonia levels may commonly occur and often return to normal with or without dosage adjustment.

Tolterodine has a moderate potential interaction with Myasthenia Gravis.

Tolterodine acts as a competitive antagonist of acetylcholine at postganglionic muscarinic receptors. Caution is recommended when using this agent in patients with myasthenia gravis, a disease characterized by decreased cholinergic activity at the neuromuscular junction.

Valproic acid has a moderate potential interaction with Psychosis.

Antiepileptic drugs (AEDs) have been associated with an increased risk of suicidal thoughts or behavior in patients taking these drugs for any indication. Pooled analyses of 199 placebo-controlled clinical studies involving the use of 11 different AEDs showed that patients receiving AEDs had approximately twice the risk of suicidal thinking or behavior compared to patients receiving placebo. AEDs should be administered cautiously in patients with depression or other psychiatric disorders; phentermine-topiramate should be avoided in patients with history of suicidal attempts or active suicidal ideation. The risk of suicidal thoughts and behavior should be carefully assessed against the risk of untreated illness, bearing in mind that epilepsy and many other conditions for which AEDs are prescribed are themselves associated with morbidity and mortality and an increased risk of suicidal thoughts and behavior. Patients, caregivers, and families should be alert to the emergence or worsening of signs and symptoms of depression, any unusual changes in mood or behavior, or the emergence of suicidal thoughts or behavior. If patients have symptoms of suicidal ideation or behavior, a dosage reduction or treatment discontinuation should be considered.

Tolterodine has a moderate potential interaction with Renal Dysfunction.

The renal elimination of tolterodine and active metabolite is limited and a prolonged half-life is not anticipated in patients with renal impairment. However, the pharmacokinetic disposition of tolterodine has not been evaluated in patients with renal impairment and it is recommended that tolterodine be administered cautiously in patients with compromised renal function.

Valproic acid has a moderate potential interaction with Thrombocytopathy.

The use of valproate derivatives may be associated with dose-related thrombocytopenia, the incidence of which is generally low but has been reported at up to 27% in one study using high dosages (approximately 50 mg/kg/day of valproic acid). In that study, platelet counts returned to normal in all patients, some despite continued treatment. Valproate may also inhibit the secondary phase of platelet aggregation, although this effect is unlikely to be of clinical significance except during the concomitant use of other drugs that affect coagulation. However, altered bleeding time, ecchymosis, petechiae, bruising, hematoma formation, epistaxis, and frank hemorrhage have been reported rarely. Hypofibrinogenemia has also been observed. Therapy with valproate products, particularly at high dosages, should be administered cautiously in patients with significant active bleeding or a hemorrhagic diathesis, including hemostatic and/or coagulation defects associated with hemophilia, vitamin K deficiency, hypoprothrombinemia, thrombocytopenia, thrombocytopathy, or severe hepatic impairment. The manufacturers recommend platelet counts and coagulation tests prior to initiating therapy and at periodic intervals thereafter, as well as before planned surgery. The dosage should be reduced or the drug withdrawn if clinical evidence of hemorrhage, bruising, or a disorder of hemostasis or coagulation occurs.

Valproic acid has a moderate potential interaction with Thrombocytopenia.

The use of valproate derivatives may be associated with dose-related thrombocytopenia, the incidence of which is generally low but has been reported at up to 27% in one study using high dosages (approximately 50 mg/kg/day of valproic acid). In that study, platelet counts returned to normal in all patients, some despite continued treatment. Valproate may also inhibit the secondary phase of platelet aggregation, although this effect is unlikely to be of clinical significance except during the concomitant use of other drugs that affect coagulation. However, altered bleeding time, ecchymosis, petechiae, bruising, hematoma formation, epistaxis, and frank hemorrhage have been reported rarely. Hypofibrinogenemia has also been observed. Therapy with valproate products, particularly at high dosages, should be administered cautiously in patients with significant active bleeding or a hemorrhagic diathesis, including hemostatic and/or coagulation defects associated with hemophilia, vitamin K deficiency, hypoprothrombinemia, thrombocytopenia, thrombocytopathy, or severe hepatic impairment. The manufacturers recommend platelet counts and coagulation tests prior to initiating therapy and at periodic intervals thereafter, as well as before planned surgery. The dosage should be reduced or the drug withdrawn if clinical evidence of hemorrhage, bruising, or a disorder of hemostasis or coagulation occurs.

Valproic acid has a moderate potential interaction with Thyroid Disease.

The manufacturers state that there have been reports of altered thyroid function tests associated with the use of valproate. However, no specific information is given. Clinicians should be cognizant of this potential effect when prescribing or administering valproate products to patients with thyroid disease.

Tolterodine has a major potential interaction with Urinary Retention.

The use of tolterodine is contraindicated in patients with GI obstruction, ileus, or obstructive uropathy. Tolterodine exerts anticholinergic activity by competitive antagonism of muscarinic receptors.

Valproic acid has a moderate potential interaction with Vitamin K Deficiency.

The use of valproate derivatives may be associated with dose-related thrombocytopenia, the incidence of which is generally low but has been reported at up to 27% in one study using high dosages (approximately 50 mg/kg/day of valproic acid). In that study, platelet counts returned to normal in all patients, some despite continued treatment. Valproate may also inhibit the secondary phase of platelet aggregation, although this effect is unlikely to be of clinical significance except during the concomitant use of other drugs that affect coagulation. However, altered bleeding time, ecchymosis, petechiae, bruising, hematoma formation, epistaxis, and frank hemorrhage have been reported rarely. Hypofibrinogenemia has also been observed. Therapy with valproate products, particularly at high dosages, should be administered cautiously in patients with significant active bleeding or a hemorrhagic diathesis, including hemostatic and/or coagulation defects associated with hemophilia, vitamin K deficiency, hypoprothrombinemia, thrombocytopenia, thrombocytopathy, or severe hepatic impairment. The manufacturers recommend platelet counts and coagulation tests prior to initiating therapy and at periodic intervals thereafter, as well as before planned surgery. The dosage should be reduced or the drug withdrawn if clinical evidence of hemorrhage, bruising, or a disorder of hemostasis or coagulation occurs.