Interactions between Chlorpheniramine and Guanfacine

Chlorpheniramine has a moderate potential interaction with Asthma.

It has been suggested that the anticholinergic effect of antihistamines may reduce the volume and cause thickening of bronchial secretions, resulting in obstruction of respiratory tract. Some manufacturers and clinicians recommend that therapy with antihistamines be administered cautiously in patients with asthma or chronic obstructive pulmonary disease.

Chlorpheniramine has a moderate potential interaction with Cardiovascular Conditions and Disorders.

Antihistamines may infrequently cause cardiovascular adverse effects related to their anticholinergic and local anesthetic (quinidine-like) activities. Tachycardia, palpitation, ECG changes, arrhythmias, hypotension, and hypertension have been reported. Although these effects are uncommon and usually limited to overdosage situations, the manufacturers and some clinicians recommend that therapy with antihistamines be administered cautiously in patients with cardiovascular disease, hypertension, and/or hyperthyroidism.

guanFACINE has a moderate potential interaction with Cerebrovascular Insufficiency.

Central alpha-2 adrenoreceptor agonists reduce sympathetic outflow from the central nervous system, resulting in decreases in heart rate, peripheral and renovascular resistance, and blood pressure. Therapy with these agents should be administered cautiously in patients with hypotension or conditions that may be exacerbated by decreased blood pressure and perfusion, such as coronary insufficiency, peripheral vascular disease (e.g., Raynaud's syndrome), cerebrovascular disease, or recent myocardial infarction.

Chlorpheniramine has a moderate potential interaction with COPD.

It has been suggested that the anticholinergic effect of antihistamines may reduce the volume and cause thickening of bronchial secretions, resulting in obstruction of respiratory tract. Some manufacturers and clinicians recommend that therapy with antihistamines be administered cautiously in patients with asthma or chronic obstructive pulmonary disease.

guanFACINE has a moderate potential interaction with Depression.

Central alpha-2 adrenoreceptor agonists may occasionally cause mental depression and should be used cautiously in patients with a history of depression.

Chlorpheniramine has a moderate potential interaction with Gastrointestinal Obstruction.

Antihistamines often have anticholinergic activity, to which elderly patients are particularly sensitive. Therapy with antihistamines should be administered cautiously, if at all, in patients with preexisting conditions that are likely to be exacerbated by anticholinergic activity, such as urinary retention or obstruction; angle-closure glaucoma, untreated intraocular hypertension, or uncontrolled primary open-angle glaucoma; and gastrointestinal obstructive disorders. Conventional, first-generation antihistamines such as the ethanolamines (bromodiphenhydramine, carbinoxamine, clemastine, dimenhydrinate, diphenhydramine, doxylamine, phenyltoloxamine) tend to exhibit substantial anticholinergic effects. In contrast, the newer, relatively nonsedating antihistamines (e.g., cetirizine, fexofenadine, loratadine) reportedly have low to minimal anticholinergic activity at normally recommended dosages and may be appropriate alternatives.

Chlorpheniramine has a moderate potential interaction with Glaucoma/Intraocular Hypertension.

Antihistamines often have anticholinergic activity, to which elderly patients are particularly sensitive. Therapy with antihistamines should be administered cautiously, if at all, in patients with preexisting conditions that are likely to be exacerbated by anticholinergic activity, such as urinary retention or obstruction; angle-closure glaucoma, untreated intraocular hypertension, or uncontrolled primary open-angle glaucoma; and gastrointestinal obstructive disorders. Conventional, first-generation antihistamines such as the ethanolamines (bromodiphenhydramine, carbinoxamine, clemastine, dimenhydrinate, diphenhydramine, doxylamine, phenyltoloxamine) tend to exhibit substantial anticholinergic effects. In contrast, the newer, relatively nonsedating antihistamines (e.g., cetirizine, fexofenadine, loratadine) reportedly have low to minimal anticholinergic activity at normally recommended dosages and may be appropriate alternatives.

guanFACINE has a moderate potential interaction with Heart Block.

Central alpha-2 adrenoreceptor agonists reduce sympathetic outflow from the central nervous system. Heart rate is decreased, which may lead to or exacerbate sinus bradycardia and atrioventricular block. Therapy with central alpha-2 adrenoreceptor agonists should be administered cautiously in patients with conduction disturbances such as sinus node dysfunction or AV nodal disease.

guanFACINE has a moderate potential interaction with Hyperkinetic Syndrome of Childhood.

The safety and effectiveness of guanfacine in children under 12 years of age has not been demonstrated and its use in this age group is not recommended. However, there have been some spontaneous postmarketing reports of mania and aggressive behavioral changes in pediatric patients with attention- deficit hyperactivity disorder (ADHD) that received this drug. All patients had medical or family risks of bipolar disorder, and all of them recovered after treatment discontinuation. Hallucinations have also been reported in pediatric patients receiving guanfacine for the treatment of ADHD.

Chlorpheniramine has a moderate potential interaction with Hyperthyroidism.

Antihistamines may infrequently cause cardiovascular adverse effects related to their anticholinergic and local anesthetic (quinidine-like) activities. Tachycardia, palpitation, ECG changes, arrhythmias, hypotension, and hypertension have been reported. Although these effects are uncommon and usually limited to overdosage situations, the manufacturers and some clinicians recommend that therapy with antihistamines be administered cautiously in patients with cardiovascular disease, hypertension, and/or hyperthyroidism.

Chlorpheniramine has a moderate potential interaction with Hypotension.

Antihistamines may infrequently cause cardiovascular adverse effects related to their anticholinergic and local anesthetic (quinidine-like) activities. Tachycardia, palpitation, ECG changes, arrhythmias, hypotension, and hypertension have been reported. Although these effects are uncommon and usually limited to overdosage situations, the manufacturers and some clinicians recommend that therapy with antihistamines be administered cautiously in patients with cardiovascular disease, hypertension, and/or hyperthyroidism.

guanFACINE has a moderate potential interaction with Hypotension.

Central alpha-2 adrenoreceptor agonists reduce sympathetic outflow from the central nervous system, resulting in decreases in heart rate, peripheral and renovascular resistance, and blood pressure. Therapy with these agents should be administered cautiously in patients with hypotension or conditions that may be exacerbated by decreased blood pressure and perfusion, such as coronary insufficiency, peripheral vascular disease (e.g., Raynaud's syndrome), cerebrovascular disease, or recent myocardial infarction.

guanFACINE has a moderate potential interaction with Ischemic Heart Disease.

Central alpha-2 adrenoreceptor agonists reduce sympathetic outflow from the central nervous system, resulting in decreases in heart rate, peripheral and renovascular resistance, and blood pressure. Therapy with these agents should be administered cautiously in patients with hypotension or conditions that may be exacerbated by decreased blood pressure and perfusion, such as coronary insufficiency, peripheral vascular disease (e.g., Raynaud's syndrome), cerebrovascular disease, or recent myocardial infarction.

Chlorpheniramine has a moderate potential interaction with Liver Disease.

Limited pharmacokinetic data are available for the older, first-generation antihistamines. Many appear to be primarily metabolized by the liver, and both parent drugs and metabolites are excreted in the urine. Patients with renal and/or liver disease may be at greater risk for adverse effects from antihistamines due to drug and metabolite accumulation. Therapy with antihistamines should be administered cautiously in such patients. Lower initial dosages may be appropriate.

guanFACINE has a moderate potential interaction with Liver Disease.

Normally, approximately 50% of a guanfacine dose is eliminated unchanged by the kidney and the rest metabolized by the liver. However, neither the parent drug nor its metabolites accumulate significantly during chronic dosing in patients with severe renal impairment due to increased hepatic metabolism of the drug in these patients. Thus, initial dosage adjustments are generally not necessary in renal impairment. Dosage titration, however, should be made cautiously if hepatic function is also compromised. The pharmacokinetics of guanfacine has not been studied in patients with liver disease. The manufacturer recommends caution when the drug is used in such patients.

guanFACINE has a moderate potential interaction with Peripheral Arterial Disease.

Central alpha-2 adrenoreceptor agonists reduce sympathetic outflow from the central nervous system, resulting in decreases in heart rate, peripheral and renovascular resistance, and blood pressure. Therapy with these agents should be administered cautiously in patients with hypotension or conditions that may be exacerbated by decreased blood pressure and perfusion, such as coronary insufficiency, peripheral vascular disease (e.g., Raynaud's syndrome), cerebrovascular disease, or recent myocardial infarction.

Chlorpheniramine has a moderate potential interaction with Renal Dysfunction.

Limited pharmacokinetic data are available for the older, first-generation antihistamines. Many appear to be primarily metabolized by the liver, and both parent drugs and metabolites are excreted in the urine. Patients with renal and/or liver disease may be at greater risk for adverse effects from antihistamines due to drug and metabolite accumulation. Therapy with antihistamines should be administered cautiously in such patients. Lower initial dosages may be appropriate.

guanFACINE has a moderate potential interaction with Renal Dysfunction.

Normally, approximately 50% of a guanfacine dose is eliminated unchanged by the kidney and the rest metabolized by the liver. However, neither the parent drug nor its metabolites accumulate significantly during chronic dosing in patients with severe renal impairment due to increased hepatic metabolism of the drug in these patients. Thus, initial dosage adjustments are generally not necessary in renal impairment. Dosage titration, however, should be made cautiously if hepatic function is also compromised. The pharmacokinetics of guanfacine has not been studied in patients with liver disease. The manufacturer recommends caution when the drug is used in such patients.

guanFACINE has a moderate potential interaction with Sinus Node Dysfunction.

Central alpha-2 adrenoreceptor agonists reduce sympathetic outflow from the central nervous system. Heart rate is decreased, which may lead to or exacerbate sinus bradycardia and atrioventricular block. Therapy with central alpha-2 adrenoreceptor agonists should be administered cautiously in patients with conduction disturbances such as sinus node dysfunction or AV nodal disease.

Chlorpheniramine has a moderate potential interaction with Urinary Retention.

Antihistamines often have anticholinergic activity, to which elderly patients are particularly sensitive. Therapy with antihistamines should be administered cautiously, if at all, in patients with preexisting conditions that are likely to be exacerbated by anticholinergic activity, such as urinary retention or obstruction; angle-closure glaucoma, untreated intraocular hypertension, or uncontrolled primary open-angle glaucoma; and gastrointestinal obstructive disorders. Conventional, first-generation antihistamines such as the ethanolamines (bromodiphenhydramine, carbinoxamine, clemastine, dimenhydrinate, diphenhydramine, doxylamine, phenyltoloxamine) tend to exhibit substantial anticholinergic effects. In contrast, the newer, relatively nonsedating antihistamines (e.g., cetirizine, fexofenadine, loratadine) reportedly have low to minimal anticholinergic activity at normally recommended dosages and may be appropriate alternatives.