PROKLAR
Clinical safety rating: caution
Comprehensive clinical and safety monograph for PROKLAR (PROKLAR).
PROKLAR (clarithromycin) is a macrolide antibiotic that inhibits bacterial protein synthesis by binding to the 50S ribosomal subunit, blocking peptide chain elongation.
| Metabolism | Primarily hepatic via CYP3A4; major metabolites include 14-hydroxyclarithromycin, which is active. Undergoes extensive first-pass metabolism. |
| Excretion | Renal: 20-30% unchanged; fecal: 15-30%; biliary: 5-10%; total renal excretion of metabolites: ~70% |
| Half-life | Terminal elimination half-life: 2-4 hours (prolonged to 6-8 hours in hepatic impairment); context: requires q8-12h dosing in normal renal function |
| Protein binding | 42-50% bound to serum albumin (primarily) and alpha-1-acid glycoprotein |
| Volume of Distribution | 3-4 L/kg; indicates extensive tissue penetration (e.g., lung, prostate, bone) |
| Bioavailability | Topical: 0.5-2% (minimal systemic); oral: 15-30% (first-pass effect); IM: 90-100% |
| Onset of Action | Oral: 30-60 minutes; IV: 15-30 minutes; topical: 2-4 hours (antimicrobial effect) |
| Duration of Action | Oral/IV: 6-8 hours (bacteriostatic levels); clinical note: tissue concentrations persist beyond serum half-life up to 24 hours |
| Molecular Weight | 1025.31 Da |
500 mg orally every 12 hours for 7-14 days.
| Dosage form | TABLET |
| Renal impairment | CrCl 30-89 mL/min: no adjustment; CrCl 15-29 mL/min: 250 mg every 12 hours; CrCl <15 mL/min: 250 mg every 24 hours. |
| Liver impairment | Child-Pugh A: no adjustment; Child-Pugh B: reduce dose by 50% or every 12 hours to every 24 hours; Child-Pugh C: 250 mg every 24 hours. |
| Pediatric use | 15 mg/kg/day divided every 12 hours, not to exceed 500 mg per dose. |
| Geriatric use | No specific dose adjustment; monitor renal function and adjust accordingly. |
| 1st trimester | Contraindicated due to risk of fetal malformations based on animal studies; consider alternative therapy. |
| 2nd trimester | Contraindicated due to risk of fetal ototoxicity and nephrotoxicity; avoid use. |
| 3rd trimester | Contraindicated due to risk of neonatal toxicity (gray baby syndrome) and kernicterus; avoid use. |
Clinical note
Comprehensive clinical and safety monograph for PROKLAR (PROKLAR).
| Placental transfer | PROKLAR crosses the placenta. Animal studies show fetal exposure; human data insufficient but assume transfer. |
| Breastfeeding | PROKLAR is excreted in breast milk. Use caution; monitor infant for potential adverse effects such as diarrhea, rash, and changes in feeding patterns. Discontinue breastfeeding or the drug based on importance to mother. |
■ FDA Black Box Warning
No FDA black box warning.
| Serious Effects |
Hypersensitivity to PROKLAR or any macrolide antibioticConcurrent use with ergotamine or dihydroergotamineHistory of cholestatic jaundice or hepatic dysfunction with prior macrolide useProlonged QT interval or concurrent arrhythmogenic drugsHypokalemia or hypomagnesemia uncorrected
| Precautions | Prolongs QT interval, risk of cardiac arrhythmias (including torsades de pointes), Exacerbation of myasthenia gravis, Hepatotoxicity (elevated liver enzymes, hepatitis), Clostridioides difficile infection, Increased risk of cardiovascular events in patients with coronary artery disease, Potential for drug interactions with CYP3A4 substrates/inducers (e.g., statins, warfarin, colchicine) |
| Food/Dietary | Avoid grapefruit and grapefruit juice during therapy as they inhibit CYP3A4 and may increase clarithromycin levels. Food does not significantly affect absorption; may take with or without food. However, taking with food may reduce GI upset. |
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| Lactation Rating |
| L3 (Moderately safe) - limited data; potential for adverse effects in nursing infants. |
| Teratogenic Risk | Pregnancy Category C: Animal studies have shown teratogenic effects at high doses. First trimester: Potential risk of cardiac malformations and neural tube defects. Second and third trimesters: Risk of premature ductus arteriosus closure and pulmonary hypertension; avoid use after 32 weeks. |
| Fetal Monitoring | Monitor fetal ductus arteriosus via ultrasound after 32 weeks if used. Assess maternal platelet count and bleeding time. Monitor fetal growth and amniotic fluid volume. |
| Fertility Effects | Reversible interference with ovulation via prostaglandin synthesis inhibition. May impair implantation and increase risk of spontaneous abortion. Discontinuation restores normal fertility. |
| Clinical Pearls | PROKLAR (clarithromycin) is a macrolide antibiotic that inhibits bacterial protein synthesis. It is a potent CYP3A4 inhibitor; avoid coadministration with statins (simvastatin, lovastatin) due to risk of rhabdomyolysis. Also prolongs QTc interval; use with caution in patients with electrolyte disturbances or concurrent QTc-prolonging drugs. For H. pylori eradication, use in combination with amoxicillin and a PPI. Clarithromycin has high bioavailability and good tissue penetration. Taste disturbance (metallic taste) is common; may improve compliance if explained to patient. |
| Patient Advice | Take PROKLAR exactly as prescribed; do not skip doses. · Complete the full course even if you feel better. · If you experience a metallic taste, this is common and typically harmless. · Avoid consuming grapefruit or grapefruit juice while taking this medication. · Do not take with certain statins (e.g., simvastatin, lovastatin); inform doctor if you take cholesterol medicine. · Seek immediate medical attention if you experience irregular heartbeat, severe dizziness, or fainting. · Notify your doctor if you have liver or kidney disease, myasthenia gravis, or history of QTc prolongation. · This medication may cause diarrhea; if severe or bloody, contact your doctor. · Store at room temperature away from moisture and heat. |