Anticonvulsants dosage

Established anticonvulsant dosage and monitoring guidelines are generally followed for use in pediatric psychiatry. 

Concomitant use with anticonvulsants (phenytoin, car-bamazepine, or phenobarbital) may induce seizures even in patients previously stabilized on anticonvulsants an anticonvulsant dosage increase may be required. 

The nurse aids continuity of anticonvulsant administration by making a notation on the care plan, as well as by informing all health care team members of the importance of the drug. If the primary health care provider discontinues the anticonvulsant tiierapy, the dosage is gradually withdrawn or another drug is gradually substituted. 

MISSELLANEOUS ANTICONVULSANTS. Valproic acid (Depakene) is unrelated chemically to the other anticonvulsants. This drug is absorbed rapidly when taken orally Tablets should not be chewed but swallowed whole to avoid irritation to the mouth and throat. The capsules may be opened and the drug sprinkled on a small amount of food, such as pudding or applesauce This mixture must be swallowed whole immediately and not chewed. Zonisamide is administered orally once a day or in divided doses. The dose may be increased by 100 mg day every 1 to 2 weeks until control of the seizures is obtained or the patient reaches the maximum dosage of 600 mg/d. 

The nurse is preparing to administer an anticonvulsant for status epilepticus. The primary care provider prescribes Luminal 200 mg IV. The drug is available in a dosage of 60 mg mL. The nurse administers... 

Isoniazid Adults S mg/kg (300 mg) Children 1 0-1 S mg/kg (300 mg) Asymptomatic elevation of aminotransferases, clinical hepatitis, fatal hepatitis, peripheral neurotoxicity, CNS system effects, lupus-like syndrome, hypersensitivity, monoamine poisoning, diarrhea LFT monthly in patients who have preexisting liver disease or who develop abnormal liver function that does not require discontinuation of drug Dosage adjustments may be necessary in patients receiving anticonvulsants or warfarin... 

Carbamazepine induces the metabolism of antidepressants, anticonvulsants, and antipsychotics, thus, dosage adjustments maybe required. 

When an isolated seizure occurs, a dosage decrease is recommended, and anticonvulsant therapy is usually not recommended. 

Alcohol withdrawal seizures do not require anticonvulsant drug treatment unless they progress to status epilepticus. Patients with seizures should be treated supportively. An increase in the dosage and slowing of the tapering schedule of the BZ used for detoxification or a single injection of a BZ may be necessary to prevent further seizure activity. 

Maintenance When clinical symptoms have subsided and the blood picture has normalized, use the dosage below. Never give less than 0.1 mg/day. Keep patients under close supervision and adjust maintenance dose if relapse appears imminent. In the presence of alcoholism, hemolytic anemia, anticonvulsant therapy, or chronic infection, the maintenance level may need to be increased. 

CNS adverse experiences CNS adverse experiences have occurred with the IV formulation, especially when recommended dosages were exceeded. They are most common in patients with CNS disorders who also have compromised renal function and are rare when no underlying CNS disorder exists. (Continue anticonvulsants in patients with a known seizure disorder.) If focal tremors, myoclonus, or seizures occur, neurologically evaluate the patient, institute anticonvulsants, re-examine the dose, and determine whether to decrease dosage or discontinue the drug. If these effects occur with the IM formulation, discontinue the drug. 

Obtain cultures Obtain cultures and determine susceptibility before treatment. Determine blood levels Determine blood levels weekly for patients having reduced renal function, for individuals receiving more than 500 mg/day, and for those with symptoms of toxicity. Adjust dosage to maintain blood level less than 30 mcg/mL. Anticonvulsant drugs or sedatives Anticonvulsant drugs or sedatives may be effective in controlling symptoms of CNS toxicity, such as convulsions, anxiety, and tremor. Closely observe patients receiving more than 500 mg/day for such symptoms. Pyridoxine may prevent CNS toxicity, but its efficacy has not been proven. 

P-450 system Monitoring of circulating cyclosporine levels and appropriate dosage adjustment are essential when drugs that affect hepatic microsomal enzymes, particularly the cytochrome P-450 3A enzymes, are used concomitantly (eg, HIV protease inhibitors, anticonvulsants, azole antifungals). 

Sustained-release formulations can produce stable serum concentrations with once or twice daily dosage. Therapeutic effects occur at blood levels > 5 mg/1, and side effects increase considerably at levels > 15 mg/1. Smoking, alcohol, anticonvulsants, and rifampicin induce the drug-metabolizing enzyme system in liver and reduce the half-life of theophylline. On the other hand, heart and liver failure, sustained fever, old age and drugs such as cimeti-dine, ciprofloxacin, and oral contraceptives reduce theophylline clearance and thereby increase serum concentrations. 

Significant drug-drug interactions are those that potentiate the effects of other agents and require dosage modification. These include certain anticoagulants, hypoglycemic sulfonylureas, and hydantoin anticonvulsants. 

Up to 30% of patients have shown a loss of anticonvulsant activity, often within 3 mo of administration dosage adjustment may reestablish efficacy... 

This drug has sedative and anticonvulsant properties. Its use in anaesthesia is now almost exclusively reserved for the management of acute withdrawal syndromes in the intensive care unit. It is thought that clomethiazole enhances GABAergic transmission in the brain. At normal dosages it has little effect on the cardiovascular system. 

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