Praziquantel

# Praziquantel ## Overview - **Classification**: Anthelmintic (anti-worm medication) - **Mechanism**: Increases cell membrane permeability to calcium ions in susceptible worms, leading to severe muscle contractions, paralysis, and detachment from host tissues. ## Primary Indications 1. **Schistosomiasis**: Treatment of all species (e.g., *S. mansoni*, *S. japonicum*, *S. haematobium*). 2. **Cestode Infections**: Treatment of various tapeworm infections (e.g., Taeniasis, Diphyllobothriasis, Hymenolepiasis). 3. **Trematode Infections**: Treatment of certain fluke infections (e.g., Clonorchiasis, Opisthorchiasis, Paragonimiasis). ## Adult Dosing ### Standard Dosing **Schistosomiasis (all species)** - **Dose**: **20 mg/kg** - **Frequency**: Every 4-6 hours, for 3 doses (total **60 mg/kg/day**) - **Route**: Oral (with food) - **Duration**: 1 day **Cestode Infections (Taeniasis, Diphyllobothriasis)** - **Dose**: **10-20 mg/kg** - **Frequency**: Single dose - **Route**: Oral (with food) - **Duration**: 1 day **Hymenolepiasis (Dwarf Tapeworm)** - **Dose**: **25 mg/kg** - **Frequency**: Single dose - **Route**: Oral (with food) - **Duration**: 1 day **Clonorchiasis, Opisthorchiasis (Liver Flukes)** - **Dose**: **25 mg/kg** - **Frequency**: Every 8 hours, for 3 doses (total **75 mg/kg/day**) - **Route**: Oral (with food) - **Duration**: 1 day **Paragonimiasis (Lung Fluke)** - **Dose**: **25 mg/kg** - **Frequency**: Every 8 hours, for 3 doses (total **75 mg/kg/day**) - **Route**: Oral (with food) - **Duration**: 2 days ### Dose Adjustments - **Renal Impairment**: No specific dose adjustment generally required. - **Hepatic Impairment**: Use with caution in severe hepatic impairment; may have reduced first-pass metabolism, leading to increased levels. Monitor for increased adverse effects. - **Elderly Patients**: No specific dose adjustment, but use with caution due to potential for reduced hepatic function. ## Pediatric Dosing ### Neonates (0-28 days) - **Dose**: Safety and efficacy **not established**. Not recommended. - **Special Notes**: Consult infectious disease specialist if considering use in this age group. ### Infants (1-12 months) - **Dose**: **20-25 mg/kg** per dose (same as adult mg/kg dosing) - **Frequency**: For schistosomiasis, **20 mg/kg** 2-3 times/day for 1 day. For cestodes, **25 mg/kg** single dose. - **Maximum**: Do not exceed adult total daily dose for the indication. - **Special Notes**: Tablets can be crushed or dissolved in liquid/soft food. ### Children (1-12 years) - **Dose**: **20-25 mg/kg** per dose (same as adult mg/kg dosing) - **Frequency**: Varies by indication (see adult dosing). - **Maximum**: Do not exceed adult total daily dose for the indication. - **Special Notes**: Tablets can be crushed or dissolved for easier administration. ### Adolescents (13-18 years) - **Dose**: Treat with adult dosing **mg/kg** regimens. - **Maximum**: Adult total daily dose. ## Safety Information ### Contraindications - **Absolute**: Hypersensitivity to praziquantel or any component. - **Absolute**: Ocular cysticercosis (destruction of parasites in the eye can cause irreversible damage). - **Absolute**: Spinal neurocysticercosis (potential for worsening neurological damage from inflammation). ### Common Adverse Effects - **Very Common (>10%)**: Dizziness, headache, malaise. - **Common (1-10%)**: Nausea, vomiting, abdominal pain/cramps, diarrhea, fever, urticaria. - **Serious but Rare**: Seizures (especially in neurocysticercosis), cardiac arrhythmias, significant allergic reactions. ### Key Drug Interactions - **CYP3A4 Inducers (e.g., Rifampin, Carbamazepine, Phenytoin)**: Significantly **decreases** praziquantel plasma levels, potentially leading to treatment failure. **Avoid co-administration** or use alternative anthelmintic. - **CYP3A4 Inhibitors (e.g., Cimetidine, Ketoconazole, Grapefruit juice)**: **Increases** praziquantel plasma levels, potentially increasing adverse effects. Monitor for increased toxicity. - **Dexamethasone**: Can reduce praziquantel plasma concentrations. Administer praziquantel **at least 1 hour before** dexamethasone. ## Monitoring & Follow-up - **Before Treatment**: Confirm diagnosis (stool/urine microscopy for ova/parasites, serology). - **During Treatment**: Monitor for CNS side effects (dizziness, drowsiness), especially in patients driving or operating machinery. - **Clinical Signs**: Watch for resolution of symptoms. Follow-up stool/urine examination 1-3 months post-treatment to confirm cure. ## Clinical Pearls - 💡 **Administration**: Always take praziquantel tablets **with food and water** to improve absorption and reduce GI upset. - 💡 **Taste**: Tablets have a bitter taste; swallowing whole is preferred. If crushing for children, mix with sugary liquid or food. - 💡 **Neurocysticercosis**: Praziquantel is generally **not recommended** for neurocysticercosis due to risk of inflammatory reactions; albendazole is preferred. - 💡 **Dizziness**: Warn patients about potential dizziness and drowsiness; advise caution with driving or operating machinery. > **⚠️ Important**: This information is for educational purposes only. Always consult current prescribing information, local guidelines, and clinical judgment before prescribing.