Action and Spectrum

Actions and spectrum: 

mequitazine is an antihistamine medication. Its action involves blocking histamine effects, a natural substance that is released during the allergic reaction.

By inhibiting histamine, mequitazine can relieve symptoms associated with allergies, such as sneezing, itching, runny nose, and watery eyes. Its spectrum of action is primarily in the treatment of allergic reactions. 

Drug Interaction

Adverse Reaction

Frequency not defined 

drowsiness 

lassitude 

incoordination 

dizziness 

Headache 

hypersensitivity reactions 

convulsions 

myalgia 

extrapyramidal effects 

Confusion 

tinnitus 

hair loss 

Jaundice 

rashes 

blood disorders 

sweating 

Paraesthesias 

tremor 

GI disturbances 

hypotension 

Photosensitivity 

Black Box Warning

Black Box Warning: 

There are no specific drug interactions associated with mequitazine. 

Contraindication / Caution

Contraindication/Caution: 

Contraindication: 

• Hypersensitivity: mequitazine should not be used in individuals who have a known hypersensitivity or allergy to the active ingredient (mequitazine) or any other components of the medication. 
• Nursing Mothers: It is not recommended for use in breastfeeding mothers because mequitazine can pass into breast milk, potentially affecting the nursing infant. 
• Infants and Neonates: mequitazine is typically not used in infants and neonates due to the lack of safety and efficacy data in this age group. 
• Alcohol: Concurrent use of alcohol with mequitazine may potentiate central nervous system (CNS) depressant effects, such as drowsiness and impaired coordination. It is advisable to avoid alcohol while taking mequitazine.

Caution: 

• Central Nervous System (CNS) Effects: mequitazine can cause drowsiness and impair coordination. Therefore, individuals taking mequitazine should use caution when performing tasks that require mental alertness, such as driving or operating heavy machinery. It is advisable to avoid activities that may be unsafe if you are experiencing drowsiness. 
• Elderly Patients: Elderly individuals may be more sensitive to the sedative effects of mequitazine. They should take extra precautions to prevent falls or accidents. 
• Liver Impairment: mequitazine is metabolized in the liver. Patients with liver impairment may need dosage adjustments or should use mequitazine with caution, as it could potentially accumulate in the body. 
• Kidney Impairment: Although mequitazine is primarily metabolized in the liver, it is still important to exercise caution in individuals with severe kidney impairment. 
• Pregnancy and Breastfeeding: mequitazine use during pregnancy and lactation should be carefully considered. While it is not recommended during breastfeeding due to the potential for transmission to the infant, the decision should be made in consultation with a healthcare provider.

Comorbidities: 

• Respiratory Conditions: Individuals with respiratory conditions like asthma or COPD should use mequitazine with caution. Some antihistamines, including mequitazine, may cause thickening of mucus secretions, which can exacerbate respiratory symptoms. 
• Cardiovascular Conditions: mequitazine may have mild cardiovascular effects, such as increasing heart rate or causing palpitations in some individuals. People with preexisting heart conditions should use mequitazine cautiously and under the guidance of a healthcare provider. 
• Alcohol Use: Combining mequitazine with alcohol can enhance the sedative effects, leading to increased drowsiness and impaired coordination. It is advisable to avoid alcohol while taking mequitazine. 
• Other Medications: mequitazine may interact with other medications, including those that also cause drowsiness, such as sedatives, tranquilizers, and certain antidepressants.  
• Glaucoma: mequitazine can increase intraocular pressure, which may be problematic for individuals with glaucoma. It is important for those with glaucoma to use mequitazine cautiously and under medical supervision. 

Pregnancy / Lactation

Pregnancy consideration:  

pregnancy category: not assigned  

Lactation: excreted into human milk: unknown  

Pregnancy category: 

• Category A: well-controlled and Satisfactory studies show no risk to the fetus in the first or later trimester. 
• <b>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: There is no data available for the drug under this category. 

Pharmacology

Pharmacology: 

mequitazine is a second-generation antihistamine with pharmacological properties that make it effective in alleviating allergy symptoms. It primarily works by blocking the effects of histamine, a chemical released in response to allergic reactions. By binding to histamine receptors in the body, mequitazine prevents histamine from exerting its effects, thereby reducing symptoms such as sneezing, runny nose, itching, and watery eyes.

Unlike earlier antihistamines, mequitazine is less likely to cause drowsiness due to its reduced penetration of the blood-brain barrier. This feature makes it a preferred choice for people seeking relief from allergies without significant sedation. mequitazine’s selective action on peripheral histamine receptors minimizes central nervous system effects, contributing to its improved safety profile.  

Pharmacodynamics: 

• Histamine Receptor Blockade: mequitazine primarily acts as an antagonist at H1 histamine receptors. By binding to these receptors, it inhibits the binding of histamine itself. This action helps to counteract the effects of histamine, which is released during allergic reactions. It reduces symptoms like itching, sneezing, runny nose, and watery eyes. 
• Antiallergic Effects: mequitazine’s histamine receptor blockade helps alleviate allergic responses. It can be particularly effective in conditions such as allergic rhinitis and urticaria. 
• Peripheral Selectivity: Second-generation antihistamines like mequitazine are designed to be more selective for peripheral H1 receptors, which are located outside the central nervous system. This selectivity minimizes sedation and drowsiness, as mequitazine has limited penetration of the blood-brain barrier. Consequently, it is less likely to cause the significant sedative effects associated with some older antihistamines. 
• Anti-Inflammatory Effects: mequitazine may possess some anti-inflammatory properties, although this effect is not as pronounced as its antihistaminic action. It can help reduce inflammation associated with allergic reactions. 
• Longer Duration of Action: mequitazine typically has a longer duration of action compared to first-generation antihistamines, allowing for less frequent dosing.

Pharmacokinetics: 

Absorption 

mequitazine is administered orally, and it is absorbed through the gastrointestinal tract. Its absorption can be influenced by factors such as food, as taking it with a meal can delay absorption. Once absorbed, it enters the bloodstream and is transported to various tissues. 

Distribution 

mequitazine is distributed throughout the body via the bloodstream. It has a high volume of distribution, indicating that it can penetrate various tissues. While it distributes into tissues, it primarily exerts its effects by binding to histamine receptors, particularly the H1 receptors located on peripheral tissues. 

Metabolism 

mequitazine undergoes extensive metabolism in the liver. The primary metabolic pathway involves the cytochrome P450 enzyme system, primarily CYP3A4. It is metabolized into several active and inactive metabolites. The main active metabolite, nor-mequitazine, also contributes to the drug’s antihistaminic effects. 

Elimination and excretion 

mequitazine and its metabolites are primarily eliminated from the body through renal excretion. After metabolism in the liver, the resulting metabolites are excreted in the urine. The elimination half-life of mequitazine can vary between individuals but is typically in the range of several hours. 

Adminstartion

Administration: 

• Dosage: mequitazine is available in various dosage forms, such as tablets or syrup. The appropriate dosage will depend on the patient’s age, weight, medical condition, and the formulation of the medication. Always use the dosage that has been prescribed by your healthcare provider. 
• Timing: mequitazine is usually taken once daily, preferably in the evening, as it may cause drowsiness. However, the dosing schedule may vary depending on the specific product and the patient’s condition. Follow the healthcare provider’s instructions regarding the timing of doses. 
• Duration: Continue taking mequitazine for the prescribed duration, even if your allergy or condition improves.  
• Storage: Store mequitazine according to the manufacturer’s instructions. Typically, it should be kept at room temperature, away from moisture and heat. Keep it out of the reach of children. 

Patient Information Leaflet

Patient information leaflet 

Generic Name: mequitazine 

Pronounced: (meh-kwuh-tuh-zeen)  

Why do we use mequitazine? 

• Allergic Rhinitis: mequitazine can help alleviate symptoms such as sneezing, runny, or stuffy nose, itching, and watery eyes in individuals with allergic rhinitis (hay fever). 
• Urticaria (Hives): It can be used to manage the itching and redness associated with acute and chronic urticaria; a skin condition characterized by the appearance of hives. 
• Pruritus (Itching): mequitazine may be prescribed to reduce itching caused by various allergic skin conditions, insect bites, or other allergic reactions. 
• Allergic Conjunctivitis: It can help relieve eye symptoms like itching and redness caused by allergic conjunctivitis.