Usage
- This fixed-dose combination medication is primarily prescribed for the symptomatic treatment of vertigo of various origins (peripheral and central). It is indicated for adults who have not responded to alternative treatments.
- Pharmacological Classification: Antihistamine (Dimenhydrinate), Calcium Channel Blocker (Cinnarizine), Antiemetic (Dimenhydrinate)
- Mechanism of Action: Cinnarizine acts by inhibiting calcium influx into vestibular hair cells and vascular smooth muscle, reducing excitability and vasospasm. Dimenhydrinate, an antihistamine, blocks H1 receptors and muscarinic acetylcholine receptors, suppressing vestibular stimulation and reducing nausea and vomiting associated with vertigo. The combination provides synergistic effects in managing vertigo symptoms.
Alternate Names
- Cinnarizine-Dimenhydrinate
- Brand Names: Cizinate, Cizere, Citigo, Arlevert, Dimezine
How It Works
- Pharmacodynamics: Cinnarizine improves blood flow in the inner ear and reduces the excitability of the vestibular system. Dimenhydrinate acts on the central nervous system to reduce nausea and vomiting and also has antihistaminic effects that alleviate vertigo symptoms.
- Pharmacokinetics:
- Absorption: Both drugs are absorbed orally. Taking the medication after meals minimizes gastric irritation.
- Metabolism: Both cinnarizine and dimenhydrinate are extensively metabolized in the liver, primarily by CYP450 enzymes.
- Elimination: The metabolites are primarily excreted renally.
- Mode of Action: Cinnarizine blocks calcium channels, while dimenhydrinate acts as an antagonist at H1 and muscarinic receptors. This combined action reduces abnormal sensory input from the vestibular system.
- Receptor Binding/Enzyme Inhibition/Neurotransmitter Modulation: Cinnarizine primarily targets calcium channels. Dimenhydrinate targets H1 histamine receptors and muscarinic acetylcholine receptors.
- Elimination Pathways: Primarily renal excretion of metabolites.
Dosage
Standard Dosage
Adults:
- One tablet (20 mg cinnarizine/40 mg dimenhydrinate) three times daily, taken orally after meals. The lowest effective dose should be used.
- Treatment duration should generally not exceed four weeks. Longer treatment requires careful reassessment of benefits and risks.
Children:
- Not recommended for use in children and adolescents under 18 years of age due to lack of safety and efficacy data.
Special Cases:
- Elderly Patients: Same dosage as adults, but with careful monitoring for adverse effects.
- Patients with Renal Impairment: Use with caution in mild to moderate impairment. Contraindicated in severe renal impairment (creatinine clearance ≤ 25 mL/min).
- Patients with Hepatic Dysfunction: Use with caution due to hepatic metabolism. Contraindicated in severe hepatic impairment.
- Patients with Comorbid Conditions: Use with caution in patients with angle-closure glaucoma, convulsions, suspected raised intracranial pressure, alcohol abuse, or urinary retention due to urethroprostatic disorders.
Clinical Use Cases
- The drug is not typically indicated for use in situations like intubation, surgical procedures, mechanical ventilation, ICU use, or emergency situations. Its primary indication is for vertigo management in an outpatient setting.
Dosage Adjustments
- Dosage adjustments may be necessary based on individual patient response and tolerability. Consider reducing the dose or increasing the dosing interval in patients with mild to moderate renal impairment.
Side Effects
Common Side Effects
- Drowsiness, sedation, fatigue
- Dry mouth
- Headache
- Gastrointestinal discomfort (nausea, vomiting, constipation)
Rare but Serious Side Effects
- Allergic reactions (skin rash, itching, swelling)
- Extrapyramidal symptoms (tremors, muscle rigidity)
- Cholestatic jaundice
Long-Term Effects
- Potential for dependence with long-term use of dimenhydrinate.
- Chronic use may lead to tolerance, requiring dosage adjustments.
Adverse Drug Reactions (ADR)
- Severe allergic reactions (anaphylaxis)
- Agranulocytosis
Contraindications
- Hypersensitivity to cinnarizine, dimenhydrinate, diphenhydramine, or any component of the formulation
- Severe renal impairment (creatinine clearance ≤ 25 mL/min)
- Severe hepatic impairment
- Pregnancy and lactation
- Angle-closure glaucoma
- Convulsions
- Suspected raised intracranial pressure
- Alcohol abuse
- Urinary retention due to urethroprostatic disorders
- Hypersensitivity to other antihistamines with similar structures
Drug Interactions
- Alcohol: Increased sedation.
- Other CNS depressants (e.g., sedatives, hypnotics, opioids): Additive sedative effects.
- Anticholinergic drugs: May potentiate anticholinergic effects (e.g., dry mouth, urinary retention).
- Tricyclic antidepressants: May increase the risk of anticholinergic effects.
- MAO inhibitors: May prolong and intensify the anticholinergic effects of dimenhydrinate.
Pregnancy and Breastfeeding
- Pregnancy Safety Category: Contraindicated during pregnancy due to potential fetal risks.
- Breastfeeding: Contraindicated during breastfeeding as the drug is excreted in breast milk and may cause adverse effects in the neonate.
Drug Profile Summary
- Mechanism of Action: Cinnarizine: calcium channel blocker; Dimenhydrinate: antihistamine, antiemetic.
- Side Effects: Drowsiness, dry mouth, headache, gastrointestinal discomfort. Rarely: allergic reactions, extrapyramidal symptoms.
- Contraindications: Hypersensitivity, severe renal/hepatic impairment, pregnancy, breastfeeding, glaucoma, convulsions.
- Drug Interactions: Alcohol, CNS depressants, anticholinergics, tricyclic antidepressants.
- Pregnancy & Breastfeeding: Contraindicated.
- Dosage: Adults: 1 tablet (20mg/40mg) three times daily after meals. Maximum duration generally four weeks.
- Monitoring Parameters: Monitor for adverse effects, especially drowsiness and other CNS effects. Assess vertigo symptoms and treatment response.
Popular Combinations
- While cinnarizine and dimenhydrinate are commonly combined, there are no other routinely recommended drug combinations with this fixed-dose formulation for vertigo management.
Precautions
-
General Precautions: Evaluate patients for pre-existing conditions, allergies, and potential drug interactions before initiating therapy.
-
Specific Populations:
- Pregnant Women: Contraindicated.
- Breastfeeding Mothers: Contraindicated.
- Children & Elderly: Not recommended for children under 18. Use cautiously in the elderly.
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Lifestyle Considerations: Advise patients to avoid alcohol and activities requiring alertness (e.g., driving) due to the risk of drowsiness.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Cinnarizine + Dimenhydrinate?
A: The standard adult dose is one tablet (20 mg cinnarizine/40 mg dimenhydrinate) three times a day, taken orally after meals.
Q2: What are the common side effects of this medication?
A: Common side effects include drowsiness, dry mouth, headache, and gastrointestinal discomfort.
Q3: Can this medication be used during pregnancy or breastfeeding?
A: No, it is contraindicated during pregnancy and breastfeeding.
Q4: How long should this medication be taken?
A: Treatment duration should generally not exceed four weeks. Longer treatment should be under the guidance of a physician.
Q5: What should patients do if they experience drowsiness while taking this medication?
A: Patients experiencing drowsiness should avoid driving or operating machinery and should consult their doctor.
Q6: What should patients do if they miss a dose?
A: Patients should take the missed dose as soon as they remember, unless it is close to the time of their next dose. They should not double the dose to catch up.
Q7: Are there any specific drug interactions I should be aware of?
A: Yes, this medication can interact with alcohol, CNS depressants, anticholinergics, and some antidepressants. Always inform your doctor about all other medications you are taking.
Q8: How does Cinnarizine + Dimenhydrinate differ from taking each medication individually?
A: The fixed-dose combination offers the convenience of a single tablet and provides synergistic effects of both medications at lower individual doses. This can potentially minimize side effects compared to taking higher doses of each drug separately.
Q9: Is this medication appropriate for all types of vertigo?
A: While effective for many types of vertigo, it’s most suitable for vertigo of peripheral or central origin. It is essential to diagnose the underlying cause of vertigo to ensure appropriate treatment.
