Melatonin

The following dosing information is available for MELATONIN (melatonin):

Dosing
Administration
Dosing Information
Generic

Although pyridoxine was previously considered nontoxic even at high dosages, current evidence indicates that chronic administration of large dosages (e.g., 2 g daily) for the management of various conditions can cause severe adverse neurologic effects, and the risk to benefit of such dosages must be carefully weighed. (See Chronic Toxicity.)

Pyridoxine hydrochloride is usually administered orally; however, the drug may be given by IM, IV, or subcutaneous injection when oral administration is not feasible. In infants with seizures, pyridoxine hydrochloride should be administered by IM or IV injection.

No dosing information available.

No generic dosing information available.

The following drug interaction information is available for MELATONIN (melatonin):

Contraindicated
Severe
Moderate

There are 0 contraindications.

There are 1 severe interactions. These drug interactions can produce serious consequences in most patients. Actions required for severe interactions include, but are not limited to, discontinuing one or both agents, adjusting dosage, altering administration scheduling, and providing additional patient monitoring. Review the full interaction monograph for more information.

Drug Interaction	Drug Names
Melatonin/Strong CYP1A2 Inhibitors SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Strong CYP1A2 inhibitors may significantly increase the area-under-curve (AUC) of melatonin by inhibiting CYP1A2.(1,2) Fluvoxamine, a strong CYP1A2 inhibitor, has also been shown to increase endogenous melatonin levels. CLINICAL EFFECTS: The concurrent administration of melatonin and strong CYP1A2 inhibitors may result in significantly increased melatonin levels and subsequent side effects.(1-3) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The UK manufacturer of melatonin recommends against the concurrent use of melatonin and CYP1A2 inhibitors.(1) The Australian manufacturer of melatonin states concurrent use of melatonin and CYP1A2 inhibitors should be avoided.(2) Patients should be monitored for increased effects of melatonin when melatonin and CYP1A2 inhibitors are used concurrently. DISCUSSION: In a study, fluvoxamine increased the area-under-curve (AUC) and concentration maximum (Cmax) of melatonin by 17-fold and 12-fold, respectively.(2) In a case report, a 51 year old female with chronic primary insomnia who received 5 mg melatonin at bedtime and 75 mg fluvoxamine in the afternoon experienced increased nocturnal sleep, from 2.5 hours (drug free) to 4.2 hours (melatonin alone) up to 5.5 hours per night (melatonin with fluvoxamine). Both melatonin and fluvoxamine alone increased melatonin levels; however administration of melatonin alone increased melatonin levels more than fluvoxamine alone. Concurrent use of melatonin and fluvoxamine increased melatonin levels 20-fold when compared to the administration of melatonin alone.(3) In a study involving five males, 5 mg of melatonin daily was given for one week, then 50 mg of fluvoxamine was added (administered three hours apart. The AUC of melatonin increased at least nine-fold (p<0.05). The Cmax increased at least six-fold in melatonin (p<0.01), versus the Cmax in patients who received melatonin alone.(4) Strong CYP1A2 inhibitors include: enasidenib, fluvoxamine, and viloxazine.(5)	FLUVOXAMINE MALEATE, FLUVOXAMINE MALEATE ER, IDHIFA, QELBREE

Drug Interaction

Drug Names

Melatonin/Strong CYP1A2 Inhibitors

SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.

MECHANISM OF ACTION: Strong CYP1A2 inhibitors may significantly increase the area-under-curve (AUC) of melatonin by inhibiting CYP1A2.(1,2) Fluvoxamine, a strong CYP1A2 inhibitor, has also been shown to increase endogenous melatonin levels.

CLINICAL EFFECTS: The concurrent administration of melatonin and strong CYP1A2 inhibitors may result in significantly increased melatonin levels and subsequent side effects.(1-3)

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: The UK manufacturer of melatonin recommends against the concurrent use of melatonin and CYP1A2 inhibitors.(1) The Australian manufacturer of melatonin states concurrent use of melatonin and CYP1A2 inhibitors should be avoided.(2) Patients should be monitored for increased effects of melatonin when melatonin and CYP1A2 inhibitors are used concurrently.

DISCUSSION: In a study, fluvoxamine increased the area-under-curve (AUC) and concentration maximum (Cmax) of melatonin by 17-fold and 12-fold, respectively.(2) In a case report, a 51 year old female with chronic primary insomnia who received 5 mg melatonin at bedtime and 75 mg fluvoxamine in the afternoon experienced increased nocturnal sleep, from 2.5 hours (drug free) to 4.2

hours (melatonin alone) up to 5.5 hours per night (melatonin with fluvoxamine). Both melatonin and fluvoxamine alone increased melatonin levels; however administration of melatonin alone increased melatonin levels more than fluvoxamine alone.

Concurrent use of melatonin and fluvoxamine increased melatonin levels 20-fold when compared to the administration of melatonin alone.(3) In a study involving five males, 5 mg of melatonin daily was given for one week, then 50 mg of fluvoxamine was added (administered three hours apart. The AUC of melatonin increased at least nine-fold (p<0.05). The Cmax increased at least six-fold in melatonin (p<0.01), versus the Cmax in patients who received melatonin alone.(4) Strong CYP1A2 inhibitors include: enasidenib, fluvoxamine, and viloxazine.(5)

FLUVOXAMINE MALEATE, FLUVOXAMINE MALEATE ER, IDHIFA, QELBREE

There are 1 moderate interactions. The clinician should assess the patient’s characteristics and take action as needed. Actions required for moderate interactions include, but are not limited to, discontinuing one or both agents, adjusting dosage, altering administration.

Drug Interaction	Drug Names
Levodopa/Pyridoxine SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Pyridoxine increases levodopa metabolism, decreasing the amount of levodopa available to the central nervous system. CLINICAL EFFECTS: The pharmacologic effects of levodopa may be decreased. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Avoid pyridoxine in patients receiving levodopa alone; however, the interaction can be minimized by giving levodopa with a peripheral decarboxylase inhibitor (e.g. carbidopa, benserazide). DISCUSSION: In patients with Parkinson's disease, as little as 10 mg of pyridoxine may reverse the clinical benefits as well as the adverse effects of levodopa. Coadministration of levodopa with either carbidopa or benserazide has minimized the effects of this interaction.	INBRIJA, LEVODOPA

Drug Interaction

Drug Names

Levodopa/Pyridoxine

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: Pyridoxine increases levodopa metabolism, decreasing the amount of levodopa available to the central nervous system.

CLINICAL EFFECTS: The pharmacologic effects of levodopa may be decreased.

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: Avoid pyridoxine in patients receiving levodopa alone; however, the interaction can be minimized by giving levodopa with a peripheral decarboxylase inhibitor (e.g. carbidopa, benserazide).

DISCUSSION: In patients with Parkinson's disease, as little as 10 mg of pyridoxine may reverse the clinical benefits as well as the adverse effects of levodopa. Coadministration of levodopa with either carbidopa or benserazide has minimized the effects of this interaction.

INBRIJA, LEVODOPA

Severe List
Autoimmune disease
Systemic lupus erythematosus