metaraminol

Action and Spectrum

Actions and Spectrum 

Actions: 

• Alpha-1 Adrenergic Agonism: metaraminol is primarily an alpha-1 adrenergic agonist. It stimulates alpha-1 adrenergic receptors in various tissues, leading to constriction of blood vessels (vasoconstriction). This vasoconstrictive effect increases blood pressure and improves blood flow to vital organs. 
• Blood Pressure Elevation: The vasoconstrictive effect of metaraminol leads to an increase in systemic blood pressure. This can be useful in situations where blood pressure needs to be elevated, such as in cases of hypotension (low blood pressure) due to shock or anesthesia. 
• Peripheral Vasoconstriction: metaraminol’s vasoconstrictive action is particularly prominent in peripheral blood vessels. It helps redistribute blood flow by constricting blood vessels in less vital areas, which can help maintain blood flow to critical organs. 

Spectrum: 

• Hypotension: metaraminol is used to raise blood pressure in cases of acute hypotension, which can occur due to shock, sepsis, surgical procedures, or certain medical conditions. 
• Anesthesia Support: Patients can experience blood pressure drops during anesthesia. metaraminol may be administered to help counteract this drop and maintain adequate perfusion to vital organs. 
• Emergencies: metaraminol might be used in emergencies where rapid elevation of blood pressure is required, such as in cases of severe allergic reactions (anaphylaxis) or spinal anesthesia-induced hypotension. 
• Septic Shock: In septic shock, where low blood pressure is critical, metaraminol can support blood pressure until the underlying infection is treated. 

Drug Interaction

Adverse Reaction

Frequency not defined 

Palpitations 

Bradycardia 

Tachycardia 

Fatal arrhythmia 

Abscess formation  

Black Box Warning

Black Box Warning: 

None 

Contraindication / Caution

Contraindication/Caution: 

Contraindications: 

• Hypertension 
• Aortic stenosis 
• Pulmonary Hypertension 
• Vasoconstriction 

Cautions: 

• Coronary Artery Disease 
• Cardiac arrhythmias 
• Renal impairment 
• Liver dysfunction 
• Elderly patients 
• Pregnancy  
• Breastfeeding 
• Drug interactions 

Pregnancy / Lactation

Pregnancy consideration:  

Pregnancy Category: C 

Breastfeeding warnings:  

It is not known whether the drug is excreted in the breast milk.  

Pregnancy category: 

Category A: Well-controlled and satisfactory studies show no risk to the fetus in the initial or later trimester. 

Category B: There was no evidence of risk to the fetus in animal studies, and there were not enough studies on pregnant women. 

Category C: There was evidence of risk of adverse effects in animal reproduction studies, and no adequate evidence in human studies must take care of potential risks in pregnant women.    

Category D: adequate data with sufficient evidence of human fetal risk from various platforms, but despite the potential risk, and used only in emergency cases for potential benefits.    

Category X: Drugs listed in this category outweigh the risks over benefits. Hence, these categories of drugs need to be avoided by pregnant women.    

Category N: No data is available for the drug under this category. 

Pharmacology

Pharmacology:  

metaraminol is a selective alpha-1 adrenergic agonist. It binds to and activates alpha-1 adrenergic receptors found on smooth muscle cells in blood vessels, particularly peripheral resistance vessels. 

The vasoconstrictive action of metaraminol results in an increase in systemic vascular resistance. This increase in resistance leads to an elevation in blood pressure, making valuable metaraminol in situations where blood pressure needs to be raised. 

Pharmacodynamics: 

The increase in vascular resistance due to vasoconstriction can impact cardiac output. An increase in blood pressure can affect the heart’s workload and influence cardiac output per unit of time. 

While metaraminol’s vasoconstrictive effects are therapeutically beneficial, they can cause adverse effects such as increased heart rate (reflex tachycardia), arrhythmias, and reduced blood flow to specific tissues if excessive vasoconstriction. 

Pharmacokinetics: 

Absorption 

metaraminol is commonly administered intravenously (IV) due to its rapid and predictable onset of action. When administered intravenously, the drug enters the bloodstream directly, resulting in immediate availability for action. Intramuscular (IM) or subcutaneous (SC) administration might also be used, but these routes typically have a slower onset than IV.  

Distribution 

After entering the bloodstream, metaraminol is distributed throughout the body. It binds to alpha-1 adrenergic receptors on smooth muscle cells, particularly in blood vessels. This binding leads to vasoconstriction and an increase in blood pressure. Metabolism 

metaraminol is primarily metabolized in the liver through various enzymatic processes.  

Elimination and Excretion 

The metabolites resulting from metaraminol’s metabolism are excreted from the body primarily through the urine. The half-life of metaraminol, which is the time it takes for half of the drug to be eliminated from the body, is relatively short. This requires careful dosing and monitoring to maintain its therapeutic effects. 

Adminstartion

Administration: 

Route: Intravenous (IV) 

Dosage: Determined by a healthcare provider based on the patient’s condition and response to treatment. 

Rate of Administration: Adjusted based on the patient’s blood pressure and response, monitored closely during administration. 

Monitoring: Continuous monitoring of blood pressure, heart rate, and vital signs to ensure safety and effectiveness. 

Patient Information Leaflet

Patient information leaflet 

Generic Name: metaraminol 

Pronounced as: met-a-RAM-i-nol 

Why do we use metaraminol? 

metaraminol is commonly used to treat severe hypotension (low blood pressure) in situations like shock. During surgical procedures under anesthesia, patients can experience drops in blood pressure. metaraminol is used to counteract this anesthesia-induced hypotension and maintain adequate perfusion to essential organs. 

metaraminol can be administered in emergencies where immediate elevation of blood pressure is required, such as during severe allergic reactions (anaphylaxis) or other life-threatening situations