Usage
Cetirizine + Diethylcarbamazine is prescribed for the treatment of lymphatic filariasis (elephantiasis), loiasis, and river blindness. It is also used in the treatment of eosinophilic lung. This combination medication falls under the pharmacological classifications of antihistamine (cetirizine) and anthelmintic (diethylcarbamazine). Cetirizine works by blocking histamine H1 receptors, reducing allergic symptoms associated with parasitic infections. Diethylcarbamazine immobilizes and kills the microfilariae, and possibly adult worms, and also has anti-inflammatory properties.
Alternate Names
There are no widely recognized alternate names for the combination product itself. However, it is crucial to be aware of various regional brand names such as Cetriplus and DI Plus.
How It Works
Pharmacodynamics: Cetirizine, an H1 receptor antagonist, reduces vascular permeability, itching, and other allergic manifestations. Diethylcarbamazine immobilizes microfilariae, making them susceptible to the host’s immune system. It may also have some direct filaricidal action and additionally possesses anti-inflammatory properties.
Pharmacokinetics: Cetirizine is well-absorbed orally. Diethylcarbamazine is rapidly absorbed from the gastrointestinal tract and widely distributed in the body. Both drugs are primarily metabolized in the liver and excreted mainly through the kidneys. Diethylcarbamazine metabolites may also be excreted in the urine.
Dosage
Standard Dosage
Adults:
The standard dosage for adults is generally a single tablet containing 300mg of diethylcarbamazine and 10mg of cetirizine taken once daily with food for 21 days. However, the dose may vary depending on the specific parasitic infection and clinical response.
Children:
The combination is generally not recommended for children under 6 years of age. For children over 6, the dosage needs to be carefully determined by a physician based on the child’s weight and the specific condition being treated. Pediatric safety needs to be cautiously considered given the potential for adverse effects.
Special Cases:
- Elderly Patients: Dosage adjustment may be necessary in elderly patients with renal impairment.
- Patients with Renal Impairment: Caution is advised, and dosage modification may be required based on creatinine clearance.
- Patients with Hepatic Dysfunction: Liver function should be monitored. Dosage adjustments may be necessary in patients with significant hepatic impairment.
- Patients with Comorbid Conditions: The presence of other medical conditions, especially seizure disorders or urinary retention, requires careful consideration and monitoring.
Clinical Use Cases
The provided sources do not specify dosages for clinical use cases such as intubation, surgical procedures, mechanical ventilation, ICU use, or emergency situations. This combination is specifically indicated for certain parasitic infections and not generally used in these settings.
Dosage Adjustments
Dose adjustments should be made based on the patient’s renal and hepatic function. Patients with severe renal impairment may require a reduced dose or avoidance of the drug altogether.
Side Effects
Common Side Effects
Headache, dizziness, drowsiness, fatigue, dry mouth, nausea, vomiting, stomach upset, skin rash, fever.
Rare but Serious Side Effects
Severe allergic reactions, vision changes (night blindness, tunnel vision, vision loss), impairment of liver function, worsening of seizures.
Long-Term Effects
The potential long-term effects of this combination medication need to be monitored, particularly regarding vision changes with prolonged diethylcarbamazine use.
Adverse Drug Reactions (ADR)
Clinically significant ADRs include severe allergic reactions (anaphylaxis, angioedema), Stevens-Johnson syndrome, hepatotoxicity, and seizures.
Contraindications
Known hypersensitivity to either cetirizine or diethylcarbamazine, pregnancy, breastfeeding (unless benefits outweigh the risks as determined by a physician), severe renal impairment, urinary retention, seizure disorders.
Drug Interactions
The combination may interact with other antihistamines, antidepressants (e.g., duloxetine, fluoxetine, sertraline), anticonvulsants (e.g., pregabalin, topiramate), narcotic analgesics (e.g., morphine, methadone, oxycodone), and antipsychotics (e.g., quetiapine). Alcohol should be avoided as it may enhance the sedative effects of cetirizine.
Pregnancy and Breastfeeding
This combination is generally contraindicated during pregnancy and breastfeeding due to potential risks to the fetus or infant. If the use is deemed absolutely necessary during breastfeeding, careful monitoring of the infant is essential.
Drug Profile Summary
- Mechanism of Action: Cetirizine: H1 receptor antagonist. Diethylcarbamazine: immobilizes microfilariae, has some filaricidal activity and anti-inflammatory properties.
- Side Effects: Common: Headache, dizziness, drowsiness, fatigue, dry mouth, nausea, vomiting, stomach upset. Serious: Vision changes, hepatotoxicity, seizures.
- Contraindications: Hypersensitivity, pregnancy, breastfeeding, severe renal impairment, urinary retention, seizures.
- Drug Interactions: Other antihistamines, antidepressants, anticonvulsants, narcotic analgesics, antipsychotics, alcohol.
- Pregnancy & Breastfeeding: Contraindicated.
- Dosage: Adults: One tablet (300mg/10mg) daily with food for 21 days. Pediatric and special populations require individualized dosing.
- Monitoring Parameters: Liver function tests, renal function tests, ophthalmologic examination (especially during prolonged treatment).
Popular Combinations
Sometimes a corticosteroid might be prescribed in conjunction with Cetirizine + Diethylcarbamazine to manage severe inflammatory reactions associated with the death of microfilariae, particularly in cases of river blindness.
Precautions
- General Precautions: Assess for allergies, renal/hepatic function, history of seizures, and urinary retention before initiating treatment.
- Specific Populations: Advise pregnant and breastfeeding women against use. Exercise caution in children and elderly individuals.
- Lifestyle Considerations: Advise patients to avoid alcohol and activities requiring alertness due to the potential for drowsiness.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Cetirizine + Diethylcarbamazine?
A: The standard adult dose is one tablet (300mg diethylcarbamazine/10mg cetirizine) once daily with food for 21 days. However, dosage should be individualized based on the patient’s age, weight, renal and hepatic function, and the specific parasitic infection being treated.
Q2: What are the common side effects?
A: Common side effects include headache, dizziness, drowsiness, fatigue, dry mouth, nausea, vomiting, and stomach upset.
Q3: What are the serious side effects that require medical attention?
A: Serious side effects include allergic reactions, vision changes (night blindness, tunnel vision, vision loss), signs of liver dysfunction (jaundice, dark urine, abdominal pain), and worsening of seizures.
Q4: Can pregnant or breastfeeding women take this medication?
A: This medication is generally contraindicated in pregnancy and breastfeeding due to potential risks to the fetus/infant. Consult a physician if its use is being considered.
Q5: What are the contraindications for Cetirizine + Diethylcarbamazine?
A: Contraindications include hypersensitivity to the drug components, pregnancy, severe renal impairment, urinary retention, and seizure disorders.
Q6: Are there any drug interactions I should be aware of?
A: Yes, this medication may interact with other antihistamines, certain antidepressants, anticonvulsants, narcotic analgesics, and antipsychotics. Concomitant alcohol use should be avoided.
Q7: What monitoring is required during treatment?
A: Monitor liver and kidney function, and conduct regular eye examinations, especially during long-term therapy.
Q8: What patient education should be provided?
A: Advise patients about potential side effects like drowsiness and dizziness, and the need to avoid alcohol and activities requiring alertness. Instruct patients to report any vision changes or signs of allergic reactions immediately.
Q9: How does this medication work against filarial infections?
A: Diethylcarbamazine immobilizes the microfilariae, making them more susceptible to the host’s immune defenses. It might also exhibit direct filaricidal activity and possess anti-inflammatory properties. Cetirizine helps to control allergic reactions that can occur due to the parasite or the treatment.
