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Nuvigil (Armodafinil) - Drug Interactions, Contraindications, Overdosage, etc

 
 



DRUG INTERACTIONS

Drug-Drug Interactions

The existence of multiple pathways for armodafinil metabolism, as well as the fact that a non-CYP-related pathway is the most rapid in metabolizing armodafinil, suggest that there is a low probability of substantive effects on the overall pharmacokinetic profile of NUVIGIL due to CYP inhibition by concomitant medications.

In vitro data demonstrated that armodafinil shows a weak inductive response for CYP1A2 and possibly CYP3A activities in a concentration-related manner and that CYP2C19 activity is reversibly inhibited by armodafinil. Other CYP activities did not appear to be affected by armodafinil. An in vitro study demonstrated that armodafinil is a substrate of P-glycoprotein.

Chronic administration of NUVIGIL at 250 mg reduced the systemic exposure to midazolam by 32% and 17% after single oral (5 mg) and intravenous (2 mg) doses, respectively, suggesting that administration of NUVIGIL moderately induces CYP3A activity. Drugs that are substrates for CYP3A4/5, such as cyclosporine, may require dosage adjustment. (See PRECAUTIONS, Drug Interactions).

Chronic administration of NUVIGIL at 250 mg did not affect the pharmacokinetics of caffeine (200 mg), a probe substrate for CYP1A2 activity.

Coadministration of a single 400-mg dose of NUVIGIL with omeprazole (40 mg) increased systemic exposure to omeprazole by approximately 40%, indicating that armodafinil moderately inhibits CYP2C19 activity. Drugs that are substrates for CYP2C19 may require dosage reduction. (See PRECAUTIONS, Drug Interactions).

OVERDOSAGE

Human Experience

There were no overdoses reported in the NUVIGIL clinical studies. Symptoms of NUVIGIL overdose are likely to be similar to those of modafinil. Overdose in modafinil clinical trials included excitation or agitation, insomnia, and slight or moderate elevations in hemodynamic parameters. From post-marketing experience with modafinil, there have been no reports of fatal overdoses involving modafinil alone (doses up to 12 grams). Overdoses involving multiple drugs, including modafinil, have resulted in fatal outcomes. Symptoms most often accompanying modafinil overdose, alone or in combination with other drugs have included; insomnia; central nervous system symptoms such as restlessness, disorientation, confusion, excitation and hallucination; digestive changes such as nausea and diarrhea; and cardiovascular changes such as tachycardia, bradycardia, hypertension and chest pain.

Overdose Management

No specific antidote exists for the toxic effects of a NUVIGIL overdose. Such overdoses should be managed with primarily supportive care, including cardiovascular monitoring. If there are no contraindications, induced emesis or gastric lavage should be considered. There are no data to suggest the utility of dialysis or urinary acidification or alkalinization in enhancing drug elimination. The physician should consider contacting a poison-control center for advice in the treatment of any overdose.

CONTRAINDICATIONS

NUVIGIL is contraindicated in patients with known hypersensitivity to modafinil and armodafinil or its inactive ingredients.

DRUG ABUSE AND DEPENDENCE

Controlled Substance Class

Armodafinil (NUVIGIL) is a Schedule IV controlled substance.

Abuse Potential and Dependence

Although the abuse potential of armodafinil has not been specifically studied, its abuse potential is likely to be similar to that of modafinil (PROVIGIL). In humans, modafinil produces psychoactive and euphoric effects, alterations in mood, perception, thinking and feelings typical of other CNS stimulants. In in vitro binding studies, modafinil binds to the dopamine reuptake site and causes an increase in extracellular dopamine, but no increase in dopamine release. Modafinil is reinforcing, as evidenced by its self-administration in monkeys previously trained to self-administer cocaine. In some studies, modafinil was also partially discriminated as stimulant-like. Physicians should follow patients closely, especially those with a history of drug and/or stimulant (e.g., methylphenidate, amphetamine, or cocaine) abuse. Patients should be observed for signs of misuse or abuse (e.g., incrementation of doses or drug-seeking behavior).

The abuse potential of modafinil (200, 400, and 800 mg) was assessed relative to methylphenidate (45 and 90 mg) in an inpatient study in individuals experienced with drugs of abuse. Results from this clinical study demonstrated that modafinil produced psychoactive and euphoric effects and feelings consistent with other scheduled CNS stimulants (methylphenidate).

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