Carbamyl

Uses

Indicated mainly in allergic conditions including urticaria, sensitivity reactions, angioneurotic oedema, seasonal hay fever, vasomotor rhinitis, cough, common cold, motion sickness.

Diethylcarbamazine is used for Filariasis, Lymphatic filariasis, Pulmonary eosinophilia, Loiasis, Toxocariasis.

Carbamyl is also used to associated treatment for these conditions: Allergic Contact Dermatitis, Allergic Reaction, Allergic Rhinitis (AR), Allergic cough, Allergies, Allergies caused by Serum, Allergy to House Dust, Allergy to vaccine, Angioneurotic Edema, Asthma, Bronchial Asthma, Bronchitis, Common Cold, Conjunctival congestion, Conjunctivitis, Conjunctivitis allergic, Cough, Cough caused by Common Cold, Coughing caused by Flu caused by Influenza, Drug Allergy, Eye allergy, Fever, Flu caused by Influenza, Food Allergy, Headache, Headache caused by Allergies, Itching of the nose, Itching of the throat, Migraine, Nasal Congestion, Nasal Congestion caused by Common Cold, Pollen Allergy, Productive cough, Pruritus, Rash, Rhinorrhoea, Seasonal Allergic Conjunctivitis, Sinus Congestion, Sinusitis, Sneezing, Transfusion Reactions, Upper Respiratory Tract Infection, Upper respiratory tract hypersensitivity reaction, site unspecified, Urticaria, Vasomotor Rhinitis, Acute Rhinitis, Allergic purpura, Conjunctival hyperemia, Dry cough, Excess mucus or phlegm, Itchy throat, Mild bacterial upper respiratory tract infections, Ocular hyperemia, Throat inflammation, Upper airway congestion, Upper respiratory symptoms, Watery eyes, Watery itchy eyes, Airway secretion clearance therapyFilarial Infection, Onchocerciasis

How Carbamyl works

Chlorpheniramine binds to the histamine H1 receptor. This blocks the action of endogenous histamine, which subsequently leads to temporary relief of the negative symptoms brought on by histamine.

The mechanism of action of diethylcarbamazine is thought to involve sensitizing the microfilariae to phagocytosis. One study showed that diethylcarbamazine's activity against Brugia malayi microfilariae is dependent on inducible nitric-oxide synthase and the cyclooxygenase pathway. It confirmed the important role of the arachidonic acid metabolic pathway in diethylcarbamazine's mechanism of action in vivo and showes that in addition to its effects on the 5-lipoxygenase pathway, it targets the cyclooxygenase pathway and COX-1.

Dosage

Carbamyl dosage

Adults: 4 mg 3-4 times daily.

Children:

• Up to 1( one) year: 1 mg twice daily
• 1-5 years: 1 mg 3-4 times daily
• 6-12 years: 2 mg 3-4 times daily or as directed by the physician

Inital: 1 mg/kg/day, may increase to 6 mg/kg/day over 3 days, then maintain for 3 wk. Prophylaxis of loiasis 300 mg/wk.

Side Effects

Drowsiness, dizziness, headache, psychomotor impairment, urinary retention, dry mouth, blurred vision and gastro intestinal disturbances, paradoxical stimulation may rarely occur, especially in high dosage or in children.

Fever, headache, vomiting, dizziness, drowsiness, nausea, chills.

Potentially Fatal: Severe hypersensitivity reactions may occur especially in the treatment of onchocerciasis where rare Mazzotti reaction characterised by rash, itching, headache, muscle and joint pains, tachycardia, postural hypotension may start within 2 hr of drug administration. Encephalitis and retinal haemorrhage.

Toxicity

Oral LD50 (rat): 306 mg/kg; Oral LD50 (mice): 130 mg/kg; Oral LD50 (guinea pig): 198 mg/kg [Registry of Toxic Effects of Chemical Substances. Ed. D. Sweet, US Dept. of Health & Human Services: Cincinatti, 2010.] Also a mild reproductive toxin to women of childbearing age.

Oral LD₅₀ in rat and mouse is 1400 mg/kg and 660 mg/kg, respectively.

Precaution

Chlorpheniramine may produce mild sedation and it is advised that patients under continuous treatment should avoid operating machinery. Not recommended during pregnancy & lactation.

Patients with poor health.

Lactation: not known if excreted in breast milk.

Interaction

Alcohol, CNS depressants, anticholinergic drugs, MAOIs.

There are no known drug interactions and none well documented.

Elimination Route

Well absorbed in the gastrointestinal tract.

Readily absorbed following oral administration.

Half Life

21-27 hours

Approximately 8 hours.

Pregnancy & Breastfeeding use

Pregnancy Category B. Either animal-reproduction studies have not demonstrated a foetal risk but there are no controlled studies in pregnant women or animal-reproduction studies have shown an adverse effect (other than a decrease in fertility) that was not confirmed in controlled studies in women in the 1st trimester (and there is no evidence of a risk in later trimesters).

Pregnancy Category- X. Studies in animals or humans have demonstrated fetal abnormalities and/or there is positive evidence of human fetal risk based on adverse reaction data from investigational or marketing experience, and the risks involved in use of the drug in pregnant women clearly outweigh potential benefits.

Contraindication

There is no definite contraindication to therapy. It should be used with caution in epilepsy, prostatic hypertrophy, glaucoma and hepatic disease. The ability to drive or operate machinery may be impaired.

Pregnancy, hypersensitivity; lactation; infants, elderly or debilitated patients; impaired renal function; cardiac disease.

Innovators Monograph

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