Drug Interactions between chlorpheniramine / guaifenesin / phenylephrine and isoniazid

Food can decrease the levels of isoniazid in your body. Taking isoniazid on an empty stomach (at least 30 minutes before or 2 hours after a meal) will make it easier for your body to absorb the medication. Avoid drinking alcohol while taking isoniazid because alcohol use may increase the risk of damage to your liver and your risk of experiencing a condition known as peripheral neuropathy (i.E., weakness, numbness, and pain typically in the hands and feet). Your doctor may advise you to take a vitamin B6 (pyridoxine) supplement during your treatment to help prevent peripheral neuropathy. Isoniazid may interact with foods containing histamine or tyramine (e.G., aged cheese, cured meats such as sausages and salami, fava beans, sauerkraut, soy sauce, beer, red wine, skipjack, tuna, mackerel, salmon), which can cause symptoms like headache, sweating, flushing, palpitations, dizziness, lightheadedness, or feeling faint. These foods should generally be avoided. It is important to seek immediate medical care if you experience any severe side effects or symptoms of liver damage such as fever, chills, joint pain or swelling, unusual bleeding or bruising, skin rash, itching, loss of appetite, fatigue, nausea, vomiting, dark colored urine, and/or yellowing of the skin or eyes. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

Alcohol can increase the nervous system side effects of chlorpheniramine such as dizziness, drowsiness, and difficulty concentrating. Some people may also experience impairment in thinking and judgment. You should avoid or limit the use of alcohol while being treated with chlorpheniramine. Do not use more than the recommended dose of chlorpheniramine, and avoid activities requiring mental alertness such as driving or operating hazardous machinery until you know how the medication affects you. Talk to your doctor or pharmacist if you have any questions or concerns.

Both phenylephrine and caffeine can increase blood pressure and heart rate, and combining them may enhance these effects. Talk to your doctor before using these medications, especially if you have a history of high blood pressure or heart disease. You may need a dose adjustment or more frequent monitoring by your doctor to safely use both medications. Contact your doctor if your condition changes or you experience increased side effects. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

The use of isoniazid is contraindicated in patients with a history of hepatic injury due to this drug and acute liver disease of any etiology. Caution is advised when using the drug in patients with chronic liver disease or a history of alcoholism. This drug has been associated with severe and sometimes fatal hepatitis, which may occur even after many months of therapy. In a US Public Health Service Surveillance Study of 13,838 persons taking isoniazid, there were 8 deaths among 174 cases of hepatitis. Epidemiologic studies indicate an increased incidence with increasing age, alcohol use, and female gender. As a precautionary measure, routine monitoring of serum transaminases (SGOT, SGPT) and bilirubin may be considered, although a transient and harmless increase in serum transaminase reportedly occurs in 10% to 20% of patients, usually in the first 3 months of therapy. Patients should be advised to promptly discontinue isoniazid therapy and seek medical attention if they experience signs or symptoms suggestive of liver damage such as fever, rash, anorexia, nausea, vomiting, fatigue, right upper quadrant pain, dark urine, and jaundice. Reinstitution of the drug should occur only after symptoms and laboratory abnormalities resolve, with low and gradually increasing dosages.

Isoniazid commonly causes dose-related peripheral neuropathy, which results from the depletion of pyridoxine in the presence of the drug. The neuropathy is usually preceded by paraesthesia's of the feet and hands. Therapy with isoniazid should be administered cautiously in patients with pre-existing peripheral neuropathy or risk factors for developing the condition, such as malnutrition, diabetes and alcoholism. Careful monitoring is recommended on these patients. Pyridoxine (vitamin B6) at a dosage of 10 to 50 mg/day may prevent or attenuate isoniazid-related peripheral neuropathy and is recommended for these patients.

Sympathomimetic agents may cause adverse cardiovascular effects, particularly when used in high dosages and/or in susceptible patients. In cardiac tissues, these agents may produce positive chronotropic and inotropic effects via stimulation of beta- 1 adrenergic receptors. Cardiac output, oxygen consumption, and the work of the heart may be increased. In the peripheral vasculature, vasoconstriction may occur via stimulation of alpha-1 adrenergic receptors. Palpitations, tachycardia, arrhythmia, hypertension, reflex bradycardia, coronary occlusion, cerebral vasculitis, myocardial infarction, cardiac arrest, and death have been reported. Some of these agents, particularly ephedra alkaloids (ephedrine, ma huang, phenylpropanolamine), may also predispose patients to hemorrhagic and ischemic stroke. Therapy with sympathomimetic agents should generally be avoided or administered cautiously in patients with sensitivity to sympathomimetic amines, hyperthyroidism, or underlying cardiovascular or cerebrovascular disorders. These agents should not be used in patients with severe coronary artery disease or severe/uncontrolled hypertension.

Sympathomimetic agents may cause adverse cardiovascular effects, particularly when used in high dosages and/or in susceptible patients. In cardiac tissues, these agents may produce positive chronotropic and inotropic effects via stimulation of beta- 1 adrenergic receptors. Cardiac output, oxygen consumption, and the work of the heart may be increased. In the peripheral vasculature, vasoconstriction may occur via stimulation of alpha-1 adrenergic receptors. Palpitations, tachycardia, arrhythmia, hypertension, reflex bradycardia, coronary occlusion, cerebral vasculitis, myocardial infarction, cardiac arrest, and death have been reported. Some of these agents, particularly ephedra alkaloids (ephedrine, ma huang, phenylpropanolamine), may also predispose patients to hemorrhagic and ischemic stroke. Therapy with sympathomimetic agents should generally be avoided or administered cautiously in patients with sensitivity to sympathomimetic amines, hyperthyroidism, or underlying cardiovascular or cerebrovascular disorders. These agents should not be used in patients with severe coronary artery disease or severe/uncontrolled hypertension.

Isoniazid commonly causes dose-related peripheral neuropathy, which results from the depletion of pyridoxine in the presence of the drug. The neuropathy is usually preceded by paraesthesia's of the feet and hands. Therapy with isoniazid should be administered cautiously in patients with pre-existing peripheral neuropathy or risk factors for developing the condition, such as malnutrition, diabetes and alcoholism. Careful monitoring is recommended on these patients. Pyridoxine (vitamin B6) at a dosage of 10 to 50 mg/day may prevent or attenuate isoniazid-related peripheral neuropathy and is recommended for these patients.

Sympathomimetic agents may cause adverse cardiovascular effects, particularly when used in high dosages and/or in susceptible patients. In cardiac tissues, these agents may produce positive chronotropic and inotropic effects via stimulation of beta- 1 adrenergic receptors. Cardiac output, oxygen consumption, and the work of the heart may be increased. In the peripheral vasculature, vasoconstriction may occur via stimulation of alpha-1 adrenergic receptors. Palpitations, tachycardia, arrhythmia, hypertension, reflex bradycardia, coronary occlusion, cerebral vasculitis, myocardial infarction, cardiac arrest, and death have been reported. Some of these agents, particularly ephedra alkaloids (ephedrine, ma huang, phenylpropanolamine), may also predispose patients to hemorrhagic and ischemic stroke. Therapy with sympathomimetic agents should generally be avoided or administered cautiously in patients with sensitivity to sympathomimetic amines, hyperthyroidism, or underlying cardiovascular or cerebrovascular disorders. These agents should not be used in patients with severe coronary artery disease or severe/uncontrolled hypertension.

The use of isoniazid is contraindicated in patients with a history of hepatic injury due to this drug and acute liver disease of any etiology. Caution is advised when using the drug in patients with chronic liver disease or a history of alcoholism. This drug has been associated with severe and sometimes fatal hepatitis, which may occur even after many months of therapy. In a US Public Health Service Surveillance Study of 13,838 persons taking isoniazid, there were 8 deaths among 174 cases of hepatitis. Epidemiologic studies indicate an increased incidence with increasing age, alcohol use, and female gender. As a precautionary measure, routine monitoring of serum transaminases (SGOT, SGPT) and bilirubin may be considered, although a transient and harmless increase in serum transaminase reportedly occurs in 10% to 20% of patients, usually in the first 3 months of therapy. Patients should be advised to promptly discontinue isoniazid therapy and seek medical attention if they experience signs or symptoms suggestive of liver damage such as fever, rash, anorexia, nausea, vomiting, fatigue, right upper quadrant pain, dark urine, and jaundice. Reinstitution of the drug should occur only after symptoms and laboratory abnormalities resolve, with low and gradually increasing dosages.

Isoniazid commonly causes dose-related peripheral neuropathy, which results from the depletion of pyridoxine in the presence of the drug. The neuropathy is usually preceded by paraesthesia's of the feet and hands. Therapy with isoniazid should be administered cautiously in patients with pre-existing peripheral neuropathy or risk factors for developing the condition, such as malnutrition, diabetes and alcoholism. Careful monitoring is recommended on these patients. Pyridoxine (vitamin B6) at a dosage of 10 to 50 mg/day may prevent or attenuate isoniazid-related peripheral neuropathy and is recommended for these patients.

Isoniazid commonly causes dose-related peripheral neuropathy, which results from the depletion of pyridoxine in the presence of the drug. The neuropathy is usually preceded by paraesthesia's of the feet and hands. Therapy with isoniazid should be administered cautiously in patients with pre-existing peripheral neuropathy or risk factors for developing the condition, such as malnutrition, diabetes and alcoholism. Careful monitoring is recommended on these patients. Pyridoxine (vitamin B6) at a dosage of 10 to 50 mg/day may prevent or attenuate isoniazid-related peripheral neuropathy and is recommended for these patients.

Sympathomimetic agents may cause adverse cardiovascular effects, particularly when used in high dosages and/or in susceptible patients. In cardiac tissues, these agents may produce positive chronotropic and inotropic effects via stimulation of beta- 1 adrenergic receptors. Cardiac output, oxygen consumption, and the work of the heart may be increased. In the peripheral vasculature, vasoconstriction may occur via stimulation of alpha-1 adrenergic receptors. Palpitations, tachycardia, arrhythmia, hypertension, reflex bradycardia, coronary occlusion, cerebral vasculitis, myocardial infarction, cardiac arrest, and death have been reported. Some of these agents, particularly ephedra alkaloids (ephedrine, ma huang, phenylpropanolamine), may also predispose patients to hemorrhagic and ischemic stroke. Therapy with sympathomimetic agents should generally be avoided or administered cautiously in patients with sensitivity to sympathomimetic amines, hyperthyroidism, or underlying cardiovascular or cerebrovascular disorders. These agents should not be used in patients with severe coronary artery disease or severe/uncontrolled hypertension.

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.

Sympathomimetic agents may cause or worsen urinary difficulty in patients with prostate enlargement due to smooth muscle contraction in the bladder neck via stimulation of alpha-1 adrenergic receptors. Therapy with sympathomimetic agents should be administered cautiously in patients with hypertrophy or neoplasm of the prostate.

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.

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.

Sympathomimetic agents may cause increases in blood glucose concentrations. These effects are usually transient and slight but may be significant with dosages higher than those normally recommended. Therapy with sympathomimetic agents should be administered cautiously in patients with diabetes mellitus. Closer monitoring of blood glucose concentrations may be appropriate.

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.

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.

Sympathomimetic agents can induce transient mydriasis via stimulation of alpha-1 adrenergic receptors. In patients with anatomically narrow angles or narrow-angle glaucoma, pupillary dilation can provoke an acute attack. In patients with other forms of glaucoma, mydriasis may occasionally increase intraocular pressure. Therapy with sympathomimetic agents should be administered cautiously in patients with or predisposed to glaucoma, particularly narrow-angle glaucoma.

Isoniazid is substantially removed by hemodialysis and should be administered after dialysis.

Caution and close monitoring is advised when using isoniazid in patients with HIV seropositive patients. Patients with pulmonary tuberculosis and HIV infection may have problems with malabsorption. Screening of antimycobacterial drug levels, especially in patients with advanced HIV disease, may be necessary to prevent the emergence of multi-drug resistant tuberculosis.

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.

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.

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.

Sympathomimetic agents may cause or worsen urinary difficulty in patients with prostate enlargement due to smooth muscle contraction in the bladder neck via stimulation of alpha-1 adrenergic receptors. Therapy with sympathomimetic agents should be administered cautiously in patients with hypertrophy or neoplasm of the prostate.

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.

Isoniazid may cause cerebellar syndrome in patients with chronic kidney disease. Patients with end-stage renal disease have been reported to have an increased risk of developing tuberculosis. Careful monitoring is recommended if this drug is used in patients with severe renal dysfunction. Dosage adjustments in renal impairment are generally not necessary except in slow acetylators with a creatinine clearance below 10 mL/min. Approximately 50% of Blacks and Caucasians are slow acetylators, and most Eskimos and Asians are rapid acetylators.

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.