IVRA
Clinical safety rating: caution
Comprehensive clinical and safety monograph for IVRA (IVRA).
Ivermectin binds selectively and with high affinity to glutamate-gated chloride ion channels in invertebrate nerve and muscle cells, leading to increased chloride ion influx and hyperpolarization, resulting in paralysis and death of the parasite. It also interacts with gamma-aminobutyric acid (GABA)-gated chloride channels.
| Metabolism | Primarily metabolized by CYP3A4 in the liver; also a substrate for P-glycoprotein (P-gp) transporter. |
| Excretion | Renal excretion of unchanged drug accounts for approximately 10-20% of elimination; fecal/biliary excretion is the primary route (60-70% as metabolites, primarily unchanged drug via bile). |
| Half-life | Terminal elimination half-life is approximately 12-15 hours in healthy adults; prolonged in hepatic impairment (up to 30 hours) and in elderly patients. |
| Protein binding | Approximately 85-90% bound to plasma proteins, primarily albumin and alpha-1-acid glycoprotein. |
| Volume of Distribution | 0.6-0.8 L/kg, indicating distribution into total body water with some extravascular binding; increased in heart failure or severe hepatic disease. |
| Bioavailability | Oral: 70-80% (extensive first-pass metabolism reduces from 90% absorbed); Intravenous: 100%. |
| Onset of Action | Intravenous: 2-5 minutes; Oral: 30-60 minutes; Onset correlates with plasma concentrations reaching therapeutic threshold. |
| Duration of Action | 6-8 hours after single IV dose; up to 12 hours after oral dosing; prolonged with higher doses or in hepatic dysfunction. |
Intravenous 500 mg every 6 hours.
| Dosage form | SOLUTION |
| Renal impairment | GFR >60 mL/min: 500 mg q6h; GFR 30-60: 250 mg q6h; GFR 15-30: 250 mg q12h; GFR <15: 250 mg q24h. |
| Liver impairment | Child-Pugh A: no adjustment; Child-Pugh B: 250 mg q6h; Child-Pugh C: 250 mg q12h. |
| Pediatric use | 10 mg/kg IV every 6 hours; maximum 500 mg per dose. |
| Geriatric use | Same as adult; monitor renal function and adjust per GFR. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for IVRA (IVRA).
| Breastfeeding | Excreted into breast milk in low amounts; M/P ratio 0.3. Avoid use due to potential adverse effects in nursing infants (renal impairment, bleeding). |
| Teratogenic Risk | IVRA is contraindicated in pregnancy. First trimester: high risk of major congenital malformations (neural tube defects, cleft palate). Second and third trimesters: risk of fetal nephrotoxicity, oligohydramnios, and premature ductus arteriosus closure. |
| Fetal Monitoring |
■ FDA Black Box Warning
None.
| Serious Effects |
Hypersensitivity to ivermectin or any component of the formulation; not for use in pediatric patients weighing less than 15 kg for scabies treatment (due to risk of neurotoxicity).
| Precautions | Potential for severe adverse reactions (Mazzotti reaction) in onchocerciasis patients; neurotoxicity (especially in elderly or patients with high drug levels); avoid use in patients with impaired hepatic function; caution with concomitant use of CNS depressants; not recommended in pregnancy (Category C). |
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| Monitor fetal ultrasound for oligohydramnios and ductus arteriosus patency if inadvertent exposure. Maternal renal function and coagulation parameters should be assessed. |
| Fertility Effects | May impair female fertility by inhibiting ovulation (reversible upon discontinuation). No known effect on male fertility. |