Dosage and administration

DOSAGE AND ADMINISTRATION (see also Patient/Caregiver Package Insert) This section is intended primarily for the prescriber; however, the prescriber should also be aware of the dosing information and directions for use provided in the patient package insert. A decision to prescribe Diazepam rectal gel involves more than the diagnosis and the selection of the correct dose for the patient. First, the prescriber must be convinced from historical reports and/or personal observations that the patient exhibits the characteristic identifiable seizure cluster that can be distinguished from the patient¹s usual seizure activity by the caregiver who will be responsible for administering Diazepam rectal gel. Second, because Diazepam rectal gel is only intended for adjunctive use, the prescriber must ensure that the patient is receiving an optimal regimen of standard anti-epileptic drug treatment and is, nevertheless, continuing to experience these characteristic episodes. Third, because a non-health professional will be obliged to identify episodes suitable for treatment, make the decision to administer treatment upon that identification, administer the drug, monitor the patient, and assess the adequacy of the response to treatment, a major component of the prescribing process involves the necessary instruction of this individual. Fourth, the prescriber and caregiver must have a common understanding of what is and is not an episode of seizures that is appropriate for treatment, the timing of administration in relation to the onset of the episode, the mechanics of administering the drug, how and what to observe following administration, and what would constitute an outcome requiring immediate and direct medical attention. Calculating Prescribed Dose The Diazepam rectal gel dose should be individualized for maximum beneficial effect. The recommended dose of Diazepam rectal gel is 0.2-0.5 mg/kg depending on age. See the dosing table for specific recommendations. Age (years) Recommended Dose 2 through 5 0.5 mg/kg 6 through 11 0.3 mg/kg 12 and older 0.2 mg/kg Because Diazepam rectal gel is provided as unit doses of 2.5, 5, 7.5, 10, 12.5, 15, 17.5, and 20 mg, the prescribed dose is obtained by rounding upward to the next available dose. The following table provides acceptable weight ranges for each dose and age category, such that patients will receive between 90% and 180% of the calculated recommended dose. The safety of this strategy has been established in clinical trials. 2-5 Years 6-11 years 12+ Years 0.5 mg/kg 0.3 mg/kg 0.2 mg/kg Weight Dose Weight Dose Weight Dose (kg) (mg) (kg) (mg) (kg) (mg) 6 to 10 5 10 to 16 5 14 to 25 5 11 to 15 7.5 17 to 25 7.5 26 to 37 7.5 16 to 20 10 26 to 33 10 38 to 50 10 21 to 25 12.5 34 to 41 12.5 51 to 62 12.5 26 to 30 15 42 to 50 15 63 to 75 15 31 to 35 17.5 51 to 58 17.5 76 to 87 17.5 36 to 44 20 59 to 74 20 88 to 111 20 The rectal delivery system includes a plastic applicator with a flexible, molded tip available in two lengths. The Diastat® AcuDial™ 10-mg syringe is available with a 4.4 cm tip and the Diastat® AcuDial™ 20 mg syringe is available with a 6.0 cm tip. Diastat® 2.5 mg is also available with a 4.4 cm tip. In elderly and debilitated patients, it is recommended that the dosage be adjusted downward to reduce the likelihood of ataxia or oversedation. The prescribed dose of Diazepam rectal gel should be adjusted by the physician periodically to reflect changes in the patient¹s age or weight. The Diastat® 2.5 mg dose may also be used as a partial replacement dose for patients who may expel a portion of the first dose. Additional Dose The prescriber may wish to prescribe a second dose of Diazepam rectal gel. A second dose, when required, may be given 4-12 hours after the first dose. Treatment Frequency It is recommended that Diazepam rectal gel be used to treat no more than five episodes per month and no more than one episode every five days. Pharmacist Instructions pharmins.jpg

Pregnancy

Pregnancy Category D (see WARNINGS section)

Drug Interactions

Drug Interactions There have been no clinical studies or reports in literature to evaluate the interaction of rectally administered diazepam with other drugs. As with all drugs, the potential for interaction by a variety of mechanisms is a possibility. Effect of Concomitant Use of Benzodiazepines and Opioids: The concomitant use of benzodiazepines and opioids increases the risk of respiratory depression because of actions at different receptor sites in the CNS that control respiration. Benzodiazepines interact at GABAA sites, and opioids interact primarily at mu receptors. When benzodiazepines and opioids are combined, the potential for benzodiazepines to significantly worsen opioid-related respiratory depression exists. Limit dosage and duration of concomitant use of benzodiazepines and opioids, and follow patients closely for respiratory depression and sedation. Other Psychotropic Agents or Other CNS Depressants: If Diazepam rectal gel is to be combined with other psychotropic agents or other CNS depressants, careful consideration should be given to the pharmacology of the agents to be employed particularly with known compounds which may potentiate the action of diazepam, such as phenothiazines, narcotics, barbiturates, MAO inhibitors and other antidepressants. Cimetidine: The clearance of diazepam and certain other benzodiazepines can be delayed in association with cimetidine administration. The clinical significance of this is unclear. Valproate: Valproate may potentiate the CNS-depressant effects of diazepam. Effect of Other Drugs on Diazepam Metabolism: In vitro studies using human liver preparations suggest that CYP2C19 and CYP3A4 are the principal isozymes involved in the initial oxidative metabolism of diazepam. Therefore, potential interactions may occur when diazepam is given concurrently with agents that affect CYP2C19 and CYP3A4 activity. Potential inhibitors of CYP2C19 (e.g., cimetidine, quinidine, and tranylcypromine) and CYP3A4 (e.g., ketoconazole, troleandomycin, and clotrimazole) could decrease the rate of diazepam elimination, while inducers of CYP2C19 (e.g., rifampin) and CYP3A4 (e.g., carbamazepine, phenytoin, dexamethasone and phenobarbital) could increase the rate of elimination of diazepam. Effect of Diazepam on the Metabolism of Other Drugs: There are no reports as to which isozymes could be inhibited or induced by diazepam. But, based on the fact that diazepam is a substrate for CYP2C19 and CYP3A4, it is possible that diazepam may interfere with the metabolism of drugs which are substrates for CYP2C19, (e.g. omeprazole, propranolol, and imipramine) and CYP3A4 (e.g. cyclosporine, paclitaxel, terfenadine, theophylline, and warfarin) leading to a potential drug-drug interaction.

Indications And Usage

INDICATIONS AND USAGE Diazepam rectal gel is a gel formulation of diazepam intended for rectal administration in the management of selected, refractory, patients with epilepsy, on stable regimens of AEDs, who require intermittent use of diazepam to control bouts of increased seizure activity. Evidence to support the use of diazepam rectal gel was adduced in two controlled trials (see CLINICAL PHARMACOLOGY, CLINICAL STUDIES subsection) that enrolled patients with partial onset or generalized convulsive seizures who were identified jointly by their caregivers and physicians as suffering intermittent and periodic episodes of markedly increased seizure activity, sometimes heralded by nonconvulsive symptoms, that for the individual patient were characteristic and were deemed by the prescriber to be of a kind for which a benzodiazepine would ordinarily be administered acutely. Although these clusters or bouts of seizures differed among patients, for any individual patient the clusters of seizure activity were not only stereotypic but were judged by those conducting and participating in these studies to be distinguishable from other seizures suffered by that patient. The conclusion that a patient experienced such unique episodes of seizure activity was based on historical information.

Overdosage

Adverse Reactions

Contraindications

Nursing Mothers