pseudoephedrine/desloratadine

Action and Spectrum

Actions and Spectrum: 

Actions: 

desloratadine works by blocking the effects of histamine, a substance released by the body in an allergic reaction. Blocking histamine receptors helps alleviate allergy symptoms like itching, sneezing, runny nose, and watery eyes.  

pseudoephedrine is a nasal decongestant that works by blood vessel constriction of the nasal passages, reducing swelling and congestion. It stimulates alpha-adrenergic receptors, leading to the constriction of blood vessels in the nasal mucosa. 

Spectrum: 

desloratadine primarily targets the symptoms of allergic rhinitis, such as hay fever. It effectively reduces nasal congestion, itching, and sneezing caused by allergies. 

pseudoephedrine primarily targets nasal congestion associated with allergies or the common cold. It helps relieve stuffy nose and sinus pressure by reducing swelling in the nasal passages. 

Drug Interaction

Adverse Reaction

Frequency defined 

>10% 

Fever (12%) 

Cough (11%) 

Upper respiratory tract infection (11-21%) 

Headache (12%) 

Diarrhea (15-21%) 

Irritability (12%) 

1-10% 

Pharyngitis (4.1%) 

Dry mouth (3%) 

desloratadine 

Myalgia (2.1%) 

Macopapular rash (3%) 

Dizziness (4%) 

Emotional lability (3%) 

Erythema (3%) 

Fatigue (2.1%) 

Insomnia (5%) 

Dysmenorrhea (2.1%) 

Somnolence (2.1%) 

Urinary tract infection (4%) 

Dyspepsia (3%) 

Frequency Not Defined 

pseudoephedrine 

Hypotension 

Tachycardia 

Fatigue 

Insomnia 

Arrhythmia 

Rash 

Urticaria 

Dysuria 

Polyuria 

Nausea 

Anorexia 

Xerostomia 

Vomiting 

Ischemic colitis 

Black Box Warning

Black Box Warning: 

None 

Contraindication / Caution

Contraindication/Caution: 

Contraindications: 

• Hypersensitivity 

Cautions: 

• Cardiovascular conditions 
• Hypertension 
• Diabetes 
• Prostate conditions 
• Thyroid disorders 
• Glaucoma 
• Pregnancy 
• Bleeding 

Pregnancy / Lactation

Pregnancy consideration:  

US FDA pregnancy category: C 

Breastfeeding warnings:  

The drug is secreted in the breast milk. It causes irritability in lactated infants. 

Pregnancy category: 

• Category A: well-controlled and Satisfactory studies do not show fetal risks in the first 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 for the drug under this category is available. 

Pharmacology

Pharmacology: 

desloratadine is a second-generation antihistamine that selectively antagonizes the histamine H1 receptors. By blocking these receptors, it inhibits the effects of histamine, which gets released during an allergic reaction. desloratadine has a long duration of action and relieves allergy symptoms such as itching, sneezing, runny nose, and watery eyes. 

pseudoephedrine is a sympathomimetic drug that acts as a nasal decongestant. It stimulates alpha-adrenergic receptors, leading to vasoconstriction of blood vessels in the nasal mucosa. This constriction reduces swelling and congestion in the nasal passages, relieving nasal stuffiness associated with allergies or the common cold.

Pharmacodynamics: 

desloratadine acts as a selective antagonist of histamine H1 receptors. By binding to these receptors, desloratadine prevents histamine from exerting its effects on target tissues. Histamine is released during allergic reactions and binds to H1 receptors, leading to itching, sneezing, runny nose, and watery eyes. By blocking these receptors, desloratadine reduces or prevents the manifestation of these allergic symptoms. 

The vasoconstrictive effects of pseudoephedrine are mediated through its action on alpha-adrenergic receptors, primarily the alpha-1 receptors. This reduces blood flow and fluid leakage in the nasal mucosa, helping to alleviate congestion and promote nasal drainage. 

Pharmacokinetics: 

Absorption 

desloratadine is well-absorbed from the gastrointestinal tract after oral administration. The absolute bioavailability of desloratadine is approximately 70%. Food does not significantly affect desloratadine’s absorption, so it can be taken with or without food. 

pseudoephedrine is well-absorbed from the gastrointestinal tract after oral administration. Its bioavailability is approximately 90%. Food may slightly delay absorption but does not significantly affect the overall extent of absorption. 

Distribution 

desloratadine is extensively bound to plasma proteins, primarily to albumin. It has a relatively large volume of distribution, indicating extensive tissue distribution. 

pseudoephedrine is widely distributed throughout the body, including the nasal mucosa. It crosses the blood-brain barrier and can cause central nervous system stimulation. 

Metabolism 

desloratadine undergoes extensive metabolism in the liver, primarily through hepatic cytochrome P450 (CYP) 3A4 and 2C8 enzymes. It is metabolized to its active metabolite, 3-hydroxy desloratadine, which also has antihistaminic activity. The active metabolite undergoes further glucuronidation. 

pseudoephedrine is extensively metabolized in the liver via N-demethylation and aromatic hydroxylation. The major metabolite is methamphetamine, but the amount formed is minimal and unlikely to contribute significantly to the systemic effects. 

Elimination and Excretion 

The elimination half-life of desloratadine is approximately 27 hours. It is primarily eliminated via hepatic metabolism and subsequent renal excretion. Only a small amount of unchanged desloratadine is excreted in the urine. 

The elimination half-life of pseudoephedrine is around 4-6 hours. It is primarily eliminated via renal excretion, with approximately 44-96% of the administered dose excreted unchanged in the urine. 

Adminstartion

Administration: 

Swallow the tablet whole with a glass of water. Do not crush, chew, or break the tablet unless instructed otherwise. 

Take the medication at the recommended intervals, usually once daily. 

It can generally be taken with or without food but check the instructions or consult your healthcare provider for specific recommendations. 

Check for potential interactions with other medications you are taking. 

Take the medication regularly and as prescribed. If you miss a dose, take it as soon as you remember, but do not double dose. 

Patient Information Leaflet

Patient information leaflet 

Generic Name: desloratadine/pseudoephedrine 

Pronounced as: DES-loe-RAT-a-deen-and-SOO-doe-ee-FED-rin 

Why do we use desloratadine/pseudoephedrine? 

desloratadine/pseudoephedrine combination medication relieves symptoms associated with seasonal allergic rhinitis, also known as hay fever. It is specifically indicated for treating nasal congestion, sneezing, runny nose, itching, and watery eyes caused by allergies.