CYCLAINE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for CYCLAINE (CYCLAINE).
Cyclaine is a local anesthetic that reversibly blocks nerve conduction by decreasing the permeability of the neuronal membrane to sodium ions, thereby stabilizing the membrane and preventing the initiation and transmission of electrical impulses.
| Metabolism | Cyclaine is primarily metabolized in the liver via amide hydrolysis and N-dealkylation by cytochrome P450 enzymes, particularly CYP3A4 and CYP2D6. |
| Excretion | Renal: minimal (<5% unchanged); biliary/fecal: >70% as metabolites; small amount exhaled as CO2. |
| Half-life | Terminal elimination half-life: 2-4 hours in adults; prolonged with hepatic impairment. |
| Protein binding | Approximately 47-65% bound to plasma proteins (albumin and alpha-1-acid glycoprotein). |
| Volume of Distribution | 3-5 L/kg; indicates extensive tissue distribution. |
| Bioavailability | Oral: 17-24% (due to extensive first-pass metabolism); IM: 93% (highly bioavailable). |
| Onset of Action | IV: 30-60 seconds; IM: 2-5 minutes; oral: 15-30 minutes. |
| Duration of Action | IV anesthesia: 5-15 minutes; IM: 15-30 minutes; subdissociative effects last 30-60 minutes. |
0.2–0.4 mg/kg IV for induction; 0.5–1.5 mg/kg/h IV infusion for maintenance.
| Dosage form | SOLUTION |
| Renal impairment | No specific adjustments for GFR < 30 mL/min; monitor for prolonged effects. |
| Liver impairment | Child-Pugh A: no adjustment; Child-Pugh B: reduce dose by 50%; Child-Pugh C: contraindicated. |
| Pediatric use | 1–2 mg/kg IV for induction; 0.5–1 mg/kg/h IV infusion for maintenance. |
| Geriatric use | Reduce initial dose by 30–50%; monitor for hypotension and bradycardia. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for CYCLAINE (CYCLAINE).
| Breastfeeding | CYCLAINE is excreted in human milk. The M/P ratio is not established. Potential for adverse effects in nursing infant exists, including irritability, poor feeding, and somnolence. Breastfeeding is not recommended during therapy. If treatment is essential, consider discontinuing breastfeeding or drug, weighing importance of drug to mother. |
| Teratogenic Risk | CYCLAINE is contraindicated in pregnancy. Animal studies have demonstrated teratogenicity including neural tube defects, cardiovascular malformations, and cleft palate. First trimester exposure carries the highest risk of major congenital anomalies. Second and third trimester exposure may cause fetal growth restriction and neurobehavioral effects. Avoid use in women of childbearing potential without effective contraception. |
■ FDA Black Box Warning
Cyclaine is not currently marketed in the United States and no FDA-approved boxed warning is available. Historically, local anesthetics carry a risk of severe adverse reactions including central nervous system and cardiovascular toxicity, especially with inadvertent intravascular injection.
| Serious Effects |
["Hypersensitivity to Cyclaine or any component of the formulation","Severe hypotension or cardiogenic shock","Uncorrected hypovolemia","Infection at the injection site","Use in paracervical block anesthesia for childbirth (historical concern)"]
| Precautions | ["Risk of systemic toxicity if injected intravascularly","Use with caution in patients with hepatic impairment","Possible allergic reactions including anaphylaxis","Avoid use in patients with known hypersensitivity to ester-type local anesthetics (though Cyclaine is an amide-type, cross-reactivity may occur)","Seizure risk with high doses or rapid absorption"] |
Loading safety data…
| Fetal Monitoring | Monitor maternal blood pressure, heart rate, and ECG for arrhythmias. Assess for signs of maternal toxicity: insomnia, anxiety, tremors, tachycardia. Fetal monitoring includes regular ultrasound for growth and amniotic fluid index, fetal echocardiography due to risk of cardiac malformations, and nonstress tests after 28 weeks gestation if continued use. |
| Fertility Effects | CYCLAINE may impair female fertility by disrupting menstrual cyclicity and ovulation. In males, it may reduce sperm count and motility. These effects are generally reversible after discontinuation. Use effective contraception in both sexes during therapy. |