isometheptene, dichloralphenazone and acetaminophen

Action and Spectrum

Actions and spectrum: 

isometheptene, dichloralphenazone, and acetaminophen is a combination medication used to treat tension headaches. Each component of the medication has a different mechanism of action: 

• isometheptene: Acts as a vasoconstrictor, narrowing blood vessels in the head to reduce headache pain. 
• dichloralphenazone: Acts as a sedative and muscle relaxant, helping to reduce tension and muscle contractions that can contribute to headaches. 
• acetaminophen: Acts as a pain reliever and fever reducer by blocking the production of prostaglandins, which are substances responsible for causing pain and inflammation. 

The combination of these three drugs works together to provide relief from the symptoms of tension headaches. 

Drug Interaction

Adverse Reaction

Frequency not defined 

Transient dizziness 

Rash 

Black Box Warning

Contraindication / Caution

Contraindication/Caution: 

Contraindication: 

• Hypersensitivity or allergy reactions to the medication 
• Porphyria 
• Severe liver or kidney disease 
• Alcoholism 
• Glaucoma 
• Severe hypertension 
• Ischemic heart disease 
• Coronary artery disease 
• Significant valvular heart disease 
• Hyperthyroidism 
• Diabetes mellitus 
• Prostate hypertrophy with urinary retention

Caution: 

• Hepatic impairment: acetaminophen can cause hepatotoxicity, especially in patients with pre-existing liver disease. Care should be taken when administering this medication to patients with hepatic impairment. 
• Renal impairment: isometheptene, dichloralphenazone, and acetaminophen are primarily excreted by the kidneys. Therefore, patients with renal impairment should be closely monitored when taking this medication. 
• Cardiovascular disease: isometheptene may cause vasoconstriction and can increase blood pressure. Patients with cardiovascular disease, including hypertension, should be monitored when taking this medication. 
• Elderly patients: Elderly patients may be more sensitive to the effects of isometheptene, dichloralphenazone, and acetaminophen. They may also have pre-existing medical conditions that could make them more susceptible to adverse effects. 
• Pregnancy and breastfeeding: isometheptene, dichloralphenazone, and acetaminophen should be used with caution in pregnant and breastfeeding women. acetaminophen is considered safe during pregnancy, but isometheptene and dichloralphenazone should be avoided if possible. 
• Substance abuse history: isometheptene, dichloralphenazone, and acetaminophen have the potential for abuse and dependence.

Comorbidities: 

• Liver disease: acetaminophen can be toxic to the liver, and patients with liver disease should use this medication with caution. 
• Kidney disease: Patients with kidney disease may not be able to excrete the metabolites of acetaminophen properly, leading to a buildup of toxins in the body. 
• Cardiovascular disease: isometheptene can cause vasoconstriction, which may be harmful to patients with cardiovascular disease. 
• Hypertension: Patients with hypertension may be at risk for further elevation of blood pressure due to the vasoconstrictive effects of isometheptene. 
• Glaucoma: isometheptene can increase intraocular pressure, which may be harmful to patients with glaucoma. 
• Hyperthyroidism: isometheptene may exacerbate symptoms of hyperthyroidism, such as tachycardia and palpitations. 

Pregnancy / Lactation

Pregnancy consideration: N/A 

Lactation: N/A  

Pregnancy category: 

• Category A: Satisfactory and well-controlled studies show no risk to the fetus in the first or later trimester. 
• Category B: There is no evidence of risk to the fetus found in animal reproduction studies and there are not enough studies on pregnant women. 
• Category C: Adverse effects on the fetus found with evidence in animal reproduction studies and no adequate evidence for an effect in humans, care must be taken for potential risks in pregnant women. 
• Category D: There is adequate data available with sufficient evidence of human fetal risk from various platforms, but despite potential risks may be used only in emergency cases for potential benefits. 
• Category X: Drugs listed in this category outweigh risks over benefits These category drugs should be prohibited for pregnant women. 
• Category N: There is no data available for the drug under this category. 

Pharmacology

Pharmacology: 

isometheptene, dichloralphenazone, and acetaminophen are combined medications used to treat tension headaches. 

isometheptene is a sympathomimetic agent that acts on the adrenergic system, specifically the alpha-adrenergic receptors. It causes vasoconstriction of the dilated blood vessels in the head, which can help to relieve headaches. 

dichloralphenazone is a sedative-hypnotic agent that works on the central nervous system. It helps to reduce anxiety and promote relaxation, which can also help to relieve headaches. 

acetaminophen is a pain reliever and fever reducer that works by blocking the production of prostaglandins, which are chemicals in the body that cause pain and inflammation. 

The combination of these three drugs provides a multi-modal approach to treating tension headaches, addressing both the vascular and central components of headache pain.  

Pharmacodynamics: 

isometheptene, dichloralphenazone, and acetaminophen combination medication work together to relieve pain and constrict blood vessels in the head, which helps to relieve headaches. isometheptene is a sympathomimetic agent that acts as a vasoconstrictor, narrowing blood vessels in the brain to reduce blood flow and relieve headache pain. dichloralphenazone is a sedative that works by relaxing muscles and decreasing tension, which can also help to relieve headache pain. Acetaminophen is a pain reliever and fever reducer that works by inhibiting the production of prostaglandins, which are chemicals that cause pain and inflammation. The combination of these drugs provides a multi-faceted approach to treating headaches.  

Pharmacokinetics: 

isometheptene: 

• Absorption: Rapidly absorbed after oral administration, peak plasma concentrations reached within 1-2 hours 
• Distribution: Widely distributed throughout the body 
• Metabolism: Metabolized in the liver to inactive metabolites 
• Elimination and excretion: Excreted in the urine as metabolites 

dichloralphenazone: 

• Absorption: Well, absorbed after oral administration 
• Distribution: Widely distributed throughout the body 
• Metabolism: Metabolized in the liver to active and inactive metabolites 
• Elimination and excretion: Excreted in the urine as metabolites 

acetaminophen: 

• Absorption: Rapidly and completely absorbed after oral administration, peak plasma concentrations reached within 1-2 hours 
• Distribution: It is distributed throughout the body and crosses the placenta and is distributed into breast milk 
• Metabolism: Metabolized in the liver primarily by glucuronidation and sulfation to inactive metabolites, with a small fraction undergoing oxidation to a toxic metabolite in high doses 
• Elimination and excretion: Excreted in the urine as metabolites, with a small fraction excreted unchanged 

Adminstartion

Administration: 

isometheptene, dichloralphenazone and acetaminophen is usually administered orally in the form of a tablet. The usual adult dose is one to two tablets every four hours as needed for pain. The maximum daily dose is 6 tablets in a 24-hour period.

The medication should be taken with a full glass of water to ensure proper absorption. If the medication is prescribed for a child, the dosage and administration should be determined by a healthcare provider. 

Patient Information Leaflet

Patient information leaflet 

Generic Name: isometheptene, dichloralphenazone and acetaminophen 

Pronounced: Eye-soh-meth-EP-teen, dye-klor-al-FEN-uh-zone and uh-see-tuh-mih-noh-fen  

Why do we use isometheptene, dichloralphenazone and acetaminophen? 

isometheptene, dichloralphenazone, and acetaminophen combination is used to treat tension headaches. isometheptene works by narrowing blood vessels in the head. dichloralphenazone helps to relax muscles and acetaminophen helps to decrease the pain. This combination medication is usually used after other non-drug treatments have not been successful.