CACHMONT LC 2.5/4MG/5ML SYRUP

Indications

• Seasonal allergic rhinitis
• Chronic idiopathic urticaria

Dosage

Children: For children aged 6 to 11 years, the dose is 30 mg twice daily. For children aged 12 to 17 years, the dose is 120 mg once daily.

Adults: For adults, the recommended dose is 180 mg once daily.

Mechanism of action

Levocetirizine is an active enantiomer of cetirizine and functions as a selective antagonist of the peripheral H1 receptor. By blocking the action of histamine, a key mediator in allergic responses, it reduces symptoms such as sneezing, itching, and runny nose. It also prevents the activation of sensory neurons, thereby mitigating pruritus and swelling associated with allergic reactions.

Pharmacodynamics

Levocetirizine exhibits antihistaminic effects with a rapid onset of action. Its affinity for peripheral H1 receptors allows it to effectively reduce the symptoms of allergic rhinitis and urticaria. While it is termed 'non-sedating', some degree of sedation may still occur in sensitive individuals, although this is generally minimal compared to first-generation antihistamines.

Pharmacokinetics

Levocetirizine is well absorbed after oral administration, with peak plasma concentrations typically reached within 0.9 hours. The drug has a volume of distribution of approximately 0.4 L/kg and is primarily excreted unchanged in urine. It has a half-life of about 8 hours, allowing for once-daily dosing. In patients with renal impairment, dose adjustments may be necessary due to altered drug clearance.

Contra-indications

• Acute porphyrias

Adverse effects

• Asthenia
• Constipation
• Drowsiness
• Dry mouth
• Abdominal pain
• Aggression
• Agitation
• Angioedema
• Appetite increased
• Arthralgia
• Depression
• Diarrhoea
• Dizziness
• Fatigue
• Hallucination
• Hepatitis
• Myalgia
• Nausea
• Oedema
• Palpitations
• Paraesthesia
• Seizure
• Skin reactions
• Sleep disorders
• Suicidal ideation
• Syncope
• Tachycardia
• Taste altered
• Tremor
• Urinary disorders
• Vertigo
• Vision disorders
• Vomiting
• Weight increased

Interactions

• Other antihistamines
• Alcohol (may increase sedation)
• CNS depressants

Precautions

• Caution in renal impairment
• Patients should be advised about potential drowsiness affecting driving and skilled tasks

Pregnancy

Most manufacturers of antihistamines advise avoiding their use during pregnancy; however, there is no evidence of teratogenicity.

Breast-feeding

Most antihistamines are present in breast milk in varying amounts; although not known to be harmful, most manufacturers advise avoiding their use in mothers who are breastfeeding.

Storage

Store in a cool, dry place away from light. Keep out of reach of children.

Formulations

• Oral suspension
• Oral solution
• Tablets

Indications

• Allergic rhinitis
• Chronic urticaria

Dosage

Children: For children aged 6 to 11 years, the recommended dose is 5 mg once daily. For children aged 2 to 5 years, the dose is 1.25 mg once daily.

Adults: The usual dose for adults is 5 mg once daily.

Mechanism of action

Levocetirizine selectively inhibits histamine H1 receptors. This action prevents histamine from activating the receptor and causing effects such as smooth muscle contraction, increased permeability of vascular endothelium, histidine uptake in basophils, stimulation of cough receptors, and stimulation of flare responses in the nervous system.

Pharmacodynamics

As a second-generation histamine H1 antagonist, levocetirizine effectively reduces various allergic symptoms. It possesses a long duration of action, allowing for once-daily dosing. The therapeutic index is favorable, with studies showing that the maximal nonlethal dose is significantly higher than the therapeutic dose. Caution is advised for activities requiring full alertness and in patients predisposed to urinary retention.

Pharmacokinetics

Levocetirizine is well absorbed after oral administration, with peak plasma concentrations typically reached within approximately 1 hour. It has a volume of distribution of about 0.4 L/kg and is primarily excreted unchanged in the urine. The elimination half-life is approximately 8 to 9 hours, allowing for once-daily dosing.

Contra-indications

• Hypersensitivity to levocetirizine or any of its components
• Severe renal impairment

Adverse effects

• Drowsiness
• Fatigue
• Dry mouth
• Headache
• Gastrointestinal disturbances

Interactions

• CNS depressants may enhance sedative effects
• Alcohol may increase sedation

Precautions

• Caution in patients with a history of urinary retention
• Caution in patients with severe renal impairment
• Avoid operating machinery or driving until you know how levocetirizine affects you

Pregnancy

Levocetirizine should be used in pregnancy only if the potential benefit justifies the potential risk to the fetus.

Breast-feeding

Levocetirizine is excreted in breast milk; caution should be exercised when administering to nursing mothers.

Storage

Store at room temperature, away from moisture and heat.

Formulations

• Tablets
• Oral solution

Indications

• Asthma
• Exercise-induced bronchoconstriction
• Allergic rhinitis
• Seasonal allergic rhinitis

Dosage

Children: Refer to the BNF for Children for specific dosing information.

Adults: Refer to the BNF for specific dosing information.

Mechanism of action

Montelukast selectively binds to the cysteinyl leukotriene receptor 1 (CysLT1), inhibiting the action of leukotrienes such as LTC4, LTD4, and LTE4. This blockade prevents the bronchoconstrictive, pro-inflammatory, and mucus-secreting effects of these leukotrienes, leading to reduced airway inflammation and improved breathing in asthmatic patients.

Pharmacodynamics

The pharmacodynamic effects of montelukast include a decrease in bronchoconstriction, reduction in airway edema, and decreased mucus secretion. These effects contribute to improved pulmonary function and a reduction in asthma symptoms, such as wheezing, cough, and shortness of breath. Montelukast has been shown to improve exercise-induced bronchoconstriction and can be used as an adjunct to inhaled corticosteroids in asthma management.

Pharmacokinetics

Montelukast is rapidly absorbed following oral administration, with peak plasma concentrations occurring within 2 to 4 hours. It has a bioavailability of approximately 64%, and its absorption is not significantly affected by food. Montelukast is highly protein-bound (approximately 99%) and is primarily metabolized by the cytochrome P450 system, particularly CYP2C8 and CYP3A4. The elimination half-life is approximately 2.7 to 5.5 hours, and the drug is excreted mainly in the feces, with a small percentage eliminated in urine.

Contra-indications

• Hypersensitivity to montelukast or any of its excipients
• Severe asthma attacks

Adverse effects

• Headache
• Dizziness
• Fatigue
• Gastrointestinal disturbances (nausea, vomiting, diarrhea)
• Mood changes (including agitation, anxiety, depression)
• Skin reactions (rash, pruritus)
• Elevated liver enzymes

Interactions

• Warfarin, which may increase the risk of bleeding
• Phenobarbital, which may decrease the effectiveness of montelukast
• Rifampicin, which can reduce montelukast levels
• Other medications metabolized by CYP450 enzymes

Precautions

• Use with caution in patients with hepatic impairment
• Monitor for changes in behavior or mood
• Not indicated for the treatment of acute asthma attacks
• Patients should be advised to continue their asthma therapy as prescribed

Pregnancy

Montelukast should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Limited data available.

Breast-feeding

Montelukast is excreted in human milk. Caution should be exercised when administering to nursing mothers.

Storage

Store at room temperature, away from moisture and heat. Keep out of reach of children.

Formulations

• Tablets (10 mg)
• Chewable tablets (4 mg, 5 mg)
• Granules (4 mg)

Mechanism of action

Levocetirizine selectively inhibits histamine H₁ receptors. This action prevents histamine from activating this receptor and causing effects like smooth muscle contraction, increased permeability of vascular endothelium, histidine uptake in basophils, stimulation of cough receptors, and stimulation of flare responses in the nervous system.

Pharmacodynamics

Levocetirizine is a second generation histamine H₁ antagonist used to treat various allergic symptoms. It has a long duration of action as it is generally taken once daily, and a wide therapeutic window as animal studies show the maximal nonlethal dose is over 100x a normal dose. Patients are cautioned to avoid tasks that require complete alertness, avoid alertness, and use caution in patients with factors predisposing urinary retention.