Can cinnarizine (peripheral vasodilator) 50mg be given orally as a stat (single) dose?

Cinnarizine 50mg Oral Stat Dose Administration

Yes, cinnarizine 50mg can be given orally as a single stat dose—this is a standard therapeutic dose used in clinical practice for vestibular disorders and motion sickness. 1

Standard Dosing Evidence

• Cinnarizine 50mg is an established therapeutic dose used three times daily in controlled clinical trials for vertigo treatment, demonstrating both efficacy and safety 1
• The 50mg dose has been directly compared to combination therapy and placebo in randomized controlled trials, confirming it as a routine prescribed dose 1
• A single 50mg dose is well below toxic thresholds—pediatric overdose cases show toxicity only begins at doses exceeding 225mg (18 times the pediatric dose), with therapeutic levels in adults being approximately 275 ng/mL after 75mg dosing 2, 3

Pharmacokinetic Profile Supporting Single-Dose Safety

• Peak plasma concentration (Cmax) occurs at 3 hours post-administration with a 75mg dose achieving 275 ng/mL, indicating a 50mg stat dose would produce proportionally lower, safe levels 3
• The elimination half-life is approximately 3.6 hours for acute dosing, though this extends to 23.6 hours with chronic use due to accumulation 4, 3
• Oral bioavailability is 46.4%, meaning systemic exposure from a single oral dose is moderate and predictable 5

Clinical Safety Considerations

• The primary adverse effects are CNS depression and antihistaminic effects (sedation, drowsiness), which are dose-dependent and manageable at therapeutic doses 2
• Extrapyramidal symptoms and convulsions have only been reported in significant overdose scenarios (>225mg in children), not at therapeutic 50mg doses 2
• No cardiovascular complications (bradycardia, hemodynamic instability) have been observed at therapeutic doses, despite cinnarizine's calcium channel-blocking properties 2

Route-Specific Guidance

• Oral administration as tablets or capsules shows equivalent absorption and plasma levels, so either formulation is acceptable for stat dosing 4
• The oral route is preferred for non-emergency vestibular symptoms, as it avoids the cumulative toxicity and reversible kidney injury seen with repeated IV dosing at higher doses (>6mg/kg) 5

Monitoring Requirements

• Observe for sedation and CNS depression for 4-6 hours post-administration, as clinical effects may be delayed given the 3-hour time to peak concentration 2, 3
• No specific laboratory monitoring is required for a single stat dose in patients without pre-existing renal or hepatic dysfunction 5