Dosing & Uses
Dosage Forms & Strengths
capsule
- 20mg (Hetlioz)
Non-24-Hour Disorder
Indicated for the treatment of non-24-hour sleep-wake disorder in totally blind
20 mg PO per day taken before bedtime, at the same time every night
Smith-Magenis Syndrome
Indicated for nighttime sleep disturbances in Smith-Magenis syndrome (SMS)
Capsule: 20 mg PO 1 hr before bedtime, at same time qPM
Dosage Modifications
Renal impairment
- All severities: No dosage adjustment necessary
Hepatic impairment
- Mild-to-moderate (Child-Pugh Class A to B): No dosage adjustment necessary
- Severe (Child-Pugh Class C): Not studied
Dosing Considerations
Capsules and oral suspension are not interchangeable
Non-24-Hour disorder
- Owing to individual differences in circadian rhythms, drug effect may not occur for weeks or months
Dosage Forms & Strengths
capsule
- 20mg (Hetlioz)
oral suspension
- 4mg/mL (Hetlioz Lq)
Smith-Magenis Syndrome
Capsule
- Indicated for nighttime sleep disturbances in Smith-Magenis syndrome (SMS) in patients aged ≥16 years
- 20 mg PO 1 hr before bedtime, at same time qPM
Oral suspension
- Indicated for nighttime sleep disturbances in SMS in pediatric patients aged 3-15 years
- <3 years: No data available
-
3-15 years
- ≤28 kg: 0.7 mg/kg PO 1 hr before bedtime
- >28 kg: 20 mg PO 1 hr before bedtime
Dosage Modifications
Renal impairment
- All severities: No dosage adjustment necessary
Hepatic impairment
- Mild-to-moderate (Child-Pugh Class A to B): No dosage adjustment necessary
- Severe (Child-Pugh Class C): Not studied
Dosing Considerations
Capsules and oral suspension are not interchangeable
In patients >65 years, tasimelteon exposure increased by ~2-fold compared with younger adults
Interactions
Interaction Checker
No Results

Contraindicated
Serious - Use Alternative
Significant - Monitor Closely
Minor

Contraindicated (0)
Serious - Use Alternative (25)
- abametapir
abametapir will increase the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. For 2 weeks after abametapir application, avoid taking drugs that are CYP3A4 substrates. If not feasible, avoid use of abametapir.
abametapir will increase the level or effect of tasimelteon by affecting hepatic enzyme CYP1A2 metabolism. Avoid or Use Alternate Drug. For 2 weeks after abametapir application, avoid taking drugs that are CYP1A2 substrates. If not feasible, avoid use of abametapir. - amobarbital
amobarbital will decrease the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- apalutamide
apalutamide will decrease the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of apalutamide, a strong CYP3A4 inducer, with drugs that are CYP3A4 substrates can result in lower exposure to these medications. Avoid or substitute another drug for these medications when possible. Evaluate for loss of therapeutic effect if medication must be coadministered. Adjust dose according to prescribing information if needed.
- benzhydrocodone/acetaminophen
benzhydrocodone/acetaminophen, tasimelteon. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.
- fentanyl
fentanyl, tasimelteon. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration with other CNS depressants, such as skeletal muscle relaxants, may cause respiratory depression, hypotension, profound sedation, coma, and/or death. Consider dose reduction of either or both agents to avoid serious adverse effects. Monitor for hypotension, respiratory depression, and profound sedation.
- fentanyl intranasal
fentanyl intranasal, tasimelteon. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration with other CNS depressants, such as skeletal muscle relaxants, may cause respiratory depression, hypotension, profound sedation, coma, and/or death. Consider dose reduction of either or both agents to avoid serious adverse effects. Monitor for hypotension, respiratory depression, and profound sedation.
- fentanyl transdermal
fentanyl transdermal, tasimelteon. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration with other CNS depressants, such as skeletal muscle relaxants, may cause respiratory depression, hypotension, profound sedation, coma, and/or death. Consider dose reduction of either or both agents to avoid serious adverse effects. Monitor for hypotension, respiratory depression, and profound sedation.
- fentanyl transmucosal
fentanyl transmucosal, tasimelteon. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration with other CNS depressants, such as skeletal muscle relaxants, may cause respiratory depression, hypotension, profound sedation, coma, and/or death. Consider dose reduction of either or both agents to avoid serious adverse effects. Monitor for hypotension, respiratory depression, and profound sedation.
- fexinidazole
fexinidazole will increase the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Fexinidazole inhibits CYP3A4. Coadministration may increase risk for adverse effects of CYP3A4 substrates.
- givosiran
givosiran will increase the level or effect of tasimelteon by affecting hepatic enzyme CYP1A2 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of sensitive CYP1A2 substrates with givosiran. If unavoidable, decrease the CYP1A2 substrate dosage in accordance with approved product labeling.
- hydrocodone
hydrocodone, tasimelteon. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.
- idelalisib
idelalisib will increase the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Idelalisib is a strong CYP3A inhibitor; avoid coadministration with sensitive CYP3A substrates
- ivosidenib
ivosidenib will decrease the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of sensitive CYP3A4 substrates with ivosidenib or replace with alternative therapies. If coadministration is unavoidable, monitor patients for loss of therapeutic effect of these drugs.
- lemborexant
lemborexant, tasimelteon. Either increases effects of the other by sedation. Avoid or Use Alternate Drug. Use of lemborexant with other drugs to treat insomnia is not recommended.
- leniolisib
leniolisib will increase the level or effect of tasimelteon by affecting hepatic enzyme CYP1A2 metabolism. Avoid or Use Alternate Drug. Avoid leniolisib with CYP1A2 substrates that have a narrow therapeutic index
- lonafarnib
lonafarnib will increase the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration with sensitive CYP3A substrates. If coadministration unavoidable, monitor for adverse reactions and reduce CYP3A substrate dose in accordance with product labeling.
- metoclopramide intranasal
tasimelteon, metoclopramide intranasal. Either increases effects of the other by Other (see comment). Avoid or Use Alternate Drug. Comment: Avoid use of metoclopramide intranasal or interacting drug, depending on importance of drug to patient.
- olopatadine intranasal
tasimelteon and olopatadine intranasal both increase sedation. Avoid or Use Alternate Drug. Coadministration increases risk of CNS depression, which can lead to additive impairment of psychomotor performance and cause daytime impairment.
- oxycodone
tasimelteon and oxycodone both increase sedation. Avoid or Use Alternate Drug. Additive CNS depression may lead to hypotension, profound sedation, respiratory depression, or coma
- secobarbital
secobarbital will decrease the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- selinexor
selinexor, tasimelteon. unspecified interaction mechanism. Avoid or Use Alternate Drug. Patients treated with selinexor may experience neurological toxicities. Avoid taking selinexor with other medications that may cause dizziness or confusion.
- sufentanil SL
sufentanil SL, tasimelteon. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration may result in hypotension, profound sedation, respiratory depression, coma, and death. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.
- tucatinib
tucatinib will increase the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid concomitant use of tucatinib with CYP3A substrates, where minimal concentration changes may lead to serious or life-threatening toxicities. If unavoidable, reduce CYP3A substrate dose according to product labeling.
- valerian
valerian and tasimelteon both increase sedation. Avoid or Use Alternate Drug.
- voxelotor
voxelotor will increase the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Voxelotor increases systemic exposure of sensitive CYP3A4 substrates. Avoid coadministration with sensitive CYP3A4 substrates with a narrow therapeutic index. Consider dose reduction of the sensitive CYP3A4 substrate(s) if unable to avoid.
Monitor Closely (91)
- acrivastine
acrivastine and tasimelteon both increase sedation. Use Caution/Monitor.
- amisulpride
amisulpride and tasimelteon both increase sedation. Use Caution/Monitor.
- asenapine
asenapine and tasimelteon both increase sedation. Use Caution/Monitor.
- asenapine transdermal
asenapine transdermal and tasimelteon both increase sedation. Use Caution/Monitor.
- atazanavir
atazanavir will increase the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- avapritinib
avapritinib and tasimelteon both increase sedation. Use Caution/Monitor.
- benzhydrocodone/acetaminophen
benzhydrocodone/acetaminophen and tasimelteon both increase sedation. Use Caution/Monitor.
- bosentan
bosentan will decrease the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid coadministration of tasimelteon with strong CYP3A4 inducers
- brexanolone
brexanolone, tasimelteon. Either increases toxicity of the other by sedation. Use Caution/Monitor.
- brexpiprazole
brexpiprazole and tasimelteon both increase sedation. Use Caution/Monitor.
- brimonidine
brimonidine and tasimelteon both increase sedation. Use Caution/Monitor.
- brivaracetam
brivaracetam and tasimelteon both increase sedation. Use Caution/Monitor.
- buprenorphine subdermal implant
buprenorphine subdermal implant and tasimelteon both increase sedation. Use Caution/Monitor.
- buprenorphine transdermal
buprenorphine transdermal and tasimelteon both increase sedation. Use Caution/Monitor.
- buprenorphine, long-acting injection
tasimelteon increases toxicity of buprenorphine, long-acting injection by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of buprenorphine and benzodiazepines or other CNS depressants increases risk of adverse reactions including overdose, respiratory depression, and death. Cessation of benzodiazepines or other CNS depressants is preferred in most cases. In some cases, monitoring at a higher level of care for tapering CNS depressants may be appropriate. In others, gradually tapering a patient off of a prescribed benzodiazepine or other CNS depressant or decreasing to the lowest effective dose may be appropriate.
- cannabidiol
cannabidiol, tasimelteon. affecting hepatic enzyme CYP1A2 metabolism. Modify Therapy/Monitor Closely. Owing to the potential for both CYP1A2 induction and inhibition with the coadministration of CYP1A2 substrates and cannabidiol, consider reducing dosage adjustment of CYP1A2 substrates as clinically appropriate.
- carbamazepine
carbamazepine will decrease the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid coadministration of tasimelteon with strong CYP3A4 inducers
- cenobamate
cenobamate will decrease the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Increase dose of CYP3A4 substrate, as needed, when coadministered with cenobamate.
cenobamate, tasimelteon. Either increases effects of the other by sedation. Use Caution/Monitor. - chloramphenicol
chloramphenicol will increase the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- cigarette smoking
cigarette smoking will increase the level or effect of tasimelteon by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor. Tasimelteon exposure in smokers was lower (~40%) than in nonsmokers
- ciprofloxacin
ciprofloxacin will increase the level or effect of tasimelteon by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor. Avoid coadministration; potentially large increase in tasimelteon exposure and greater risk of adverse reactions with strong CYP1A2 inhibitors
- clarithromycin
clarithromycin will increase the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- conivaptan
conivaptan will increase the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- dabrafenib
dabrafenib will decrease the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid coadministration of tasimelteon with strong CYP3A4 inducers
- daridorexant
tasimelteon and daridorexant both increase sedation. Modify Therapy/Monitor Closely. Coadministration increases risk of CNS depression, which can lead to additive impairment of psychomotor performance and cause daytime impairment.
- darunavir
darunavir will increase the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- deutetrabenazine
tasimelteon and deutetrabenazine both increase sedation. Use Caution/Monitor.
- dexamethasone
dexamethasone will decrease the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid coadministration of tasimelteon with strong CYP3A4 inducers
- diazepam intranasal
diazepam intranasal, tasimelteon. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Coadministration may potentiate the CNS-depressant effects of each drug.
- difelikefalin
difelikefalin and tasimelteon both increase sedation. Use Caution/Monitor.
- efavirenz
efavirenz will decrease the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid coadministration of tasimelteon with strong CYP3A4 inducers
- elagolix
elagolix decreases levels of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Elagolix is a weak-to-moderate CYP3A4 inducer. Monitor CYP3A substrates if coadministered. Consider increasing CYP3A substrate dose if needed.
- elvitegravir/cobicistat/emtricitabine/tenofovir DF
elvitegravir/cobicistat/emtricitabine/tenofovir DF will increase the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- encorafenib
encorafenib, tasimelteon. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Encorafenib both inhibits and induces CYP3A4 at clinically relevant plasma concentrations. Coadministration of encorafenib with sensitive CYP3A4 substrates may result in increased toxicity or decreased efficacy of these agents.
- enzalutamide
enzalutamide will decrease the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid coadministration of tasimelteon with strong CYP3A4 inducers
- esketamine intranasal
esketamine intranasal, tasimelteon. Either increases toxicity of the other by sedation. Modify Therapy/Monitor Closely.
- eslicarbazepine acetate
eslicarbazepine acetate will decrease the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid coadministration of tasimelteon with strong CYP3A4 inducers
- ethanol
ethanol and tasimelteon both increase sedation. Use Caution/Monitor.
- etravirine
etravirine will decrease the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid coadministration of tasimelteon with strong CYP3A4 inducers
- fedratinib
fedratinib will increase the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Adjust dose of drugs that are CYP3A4 substrates as necessary.
- fexinidazole
fexinidazole will increase the level or effect of tasimelteon by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
- flibanserin
tasimelteon and flibanserin both increase sedation. Modify Therapy/Monitor Closely. Risk for sedation increased if flibanserin is coadministration with other CNS depressants.
- fluvoxamine
fluvoxamine will increase the level or effect of tasimelteon by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor. May increase adverse effects
- fosamprenavir
fosamprenavir will increase the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- fosphenytoin
fosphenytoin will decrease the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid coadministration of tasimelteon with strong CYP3A4 inducers
- gabapentin
gabapentin, tasimelteon. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of CNS depressants can result in serious, life-threatening, and fatal respiratory depression. Use lowest dose possible and monitor for respiratory depression and sedation.
- gabapentin enacarbil
gabapentin enacarbil, tasimelteon. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of CNS depressants can result in serious, life-threatening, and fatal respiratory depression. Use lowest dose possible and monitor for respiratory depression and sedation.
- ganaxolone
tasimelteon and ganaxolone both increase sedation. Use Caution/Monitor.
- imatinib
imatinib will increase the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- indinavir
indinavir will increase the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- isoniazid
isoniazid will increase the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- istradefylline
istradefylline will increase the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Istradefylline 40 mg/day increased peak levels and AUC of CYP3A4 substrates in clinical trials. This effect was not observed with istradefylline 20 mg/day. Consider dose reduction of sensitive CYP3A4 substrates.
- itraconazole
itraconazole will increase the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- ketoconazole
ketoconazole will increase the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- lasmiditan
lasmiditan, tasimelteon. Either increases effects of the other by sedation. Use Caution/Monitor. Coadministration of lasmiditan and other CNS depressant drugs, including alcohol have not been evaluated in clinical studies. Lasmiditan may cause sedation, as well as other cognitive and/or neuropsychiatric adverse reactions.
- lenacapavir
lenacapavir will increase the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Lencapavir may increase CYP3A4 substrates initiated within 9 months after last SC dose of lenacapavir, which may increase potential risk of adverse reactions of CYP3A4 substrates.
- levoketoconazole
levoketoconazole will increase the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- lopinavir
lopinavir will increase the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- lorlatinib
lorlatinib will decrease the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- methoxsalen
methoxsalen will increase the level or effect of tasimelteon by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor. Avoid coadministration; potentially large increase in tasimelteon exposure and greater risk of adverse reactions with strong CYP1A2 inhibitors
- mexiletine
mexiletine will increase the level or effect of tasimelteon by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor. Avoid coadministration; potentially large increase in tasimelteon exposure and greater risk of adverse reactions with strong CYP1A2 inhibitors
- midazolam intranasal
midazolam intranasal, tasimelteon. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Concomitant use of barbiturates, alcohol, or other CNS depressants may increase the risk of hypoventilation, airway obstruction, desaturation, or apnea and may contribute to profound and/or prolonged drug effect.
- mifepristone
mifepristone will increase the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- mitotane
mitotane will decrease the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid coadministration of tasimelteon with strong CYP3A4 inducers
- nefazodone
nefazodone will increase the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- nelfinavir
nelfinavir will increase the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- nevirapine
nevirapine will decrease the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid coadministration of tasimelteon with strong CYP3A4 inducers
- nicardipine
nicardipine will increase the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- ofloxacin
ofloxacin will increase the level or effect of tasimelteon by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor. Avoid coadministration; potentially large increase in tasimelteon exposure and greater risk of adverse reactions with strong CYP1A2 inhibitors
- oliceridine
oliceridine, tasimelteon. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.
- oxcarbazepine
oxcarbazepine will decrease the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid coadministration of tasimelteon with strong CYP3A4 inducers
- pentobarbital
pentobarbital will decrease the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid coadministration of tasimelteon with strong CYP3A4 inducers
- phenobarbital
phenobarbital will decrease the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid coadministration of tasimelteon with strong CYP3A4 inducers
- phenytoin
phenytoin will decrease the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid coadministration of tasimelteon with strong CYP3A4 inducers
- posaconazole
posaconazole will increase the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- pregabalin
pregabalin, tasimelteon. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of CNS depressants can result in serious, life-threatening, and fatal respiratory depression. Use lowest dose possible and monitor for respiratory depression and sedation.
- primaquine
primaquine will increase the level or effect of tasimelteon by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor. Avoid coadministration; potentially large increase in tasimelteon exposure and greater risk of adverse reactions with strong CYP1A2 inhibitors
- primidone
primidone will decrease the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid coadministration of tasimelteon with strong CYP3A4 inducers
- quinidine
quinidine will increase the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- remimazolam
remimazolam, tasimelteon. Either increases toxicity of the other by sedation. Modify Therapy/Monitor Closely. Coadministration may result in profound sedation, respiratory depression, coma, and/or death. Continuously monitor vital signs during sedation and recovery period if coadministered. Carefully titrate remimazolam dose if administered with opioid analgesics and/or sedative/hypnotics.
- rifabutin
rifabutin will decrease the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid coadministration of tasimelteon with strong CYP3A4 inducers
- rifampin
rifampin will decrease the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid coadministration of tasimelteon with strong CYP3A4 inducers
- rifapentine
rifapentine will decrease the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid coadministration of tasimelteon with strong CYP3A4 inducers
- ritonavir
ritonavir will increase the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- rucaparib
rucaparib will increase the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- saquinavir
saquinavir will increase the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- stiripentol
stiripentol, tasimelteon. affecting hepatic enzyme CYP1A2 metabolism. Modify Therapy/Monitor Closely. Stiripentol is a CYP1A2 inhibitor and inducer. Monitor CYP1A2 substrates coadministered with stiripentol for increased or decreased effects. CYP1A2 substrates may require dosage adjustment.
stiripentol, tasimelteon. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Stiripentol is a CYP3A4 inhibitor and inducer. Monitor CYP3A4 substrates coadministered with stiripentol for increased or decreased effects. CYP3A4 substrates may require dosage adjustment.
stiripentol, tasimelteon. Either increases effects of the other by sedation. Use Caution/Monitor. Concomitant use stiripentol with other CNS depressants, including alcohol, may increase the risk of sedation and somnolence. - tazemetostat
tazemetostat will decrease the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- tecovirimat
tecovirimat will decrease the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Tecovirimat is a weak CYP3A4 inducer. Monitor sensitive CYP3A4 substrates for effectiveness if coadministered.
- tipranavir
tipranavir will increase the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- voriconazole
voriconazole will increase the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
Minor (5)
- acetazolamide
acetazolamide will increase the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- anastrozole
anastrozole will increase the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- cyclophosphamide
cyclophosphamide will increase the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- larotrectinib
larotrectinib will increase the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- ribociclib
ribociclib will increase the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
Adverse Effects
>10%
Headache (17%)
1-10%
Increased ALT (10%)
Nightmares/abnormal dreams (10%)
Upper respiratory infections (7%)
Urinary tract infections (7%)
Postmarketing Reports
Nighttime Sleep Disturbances in Smith-Magenis Syndrome (SMS)
Warnings
Contraindications
None
Cautions
After administration, advise patients to limit activity to prepare for going to bed
May potentially impair performance of activities requiring complete mental alertness
Drug interaction overview
- Tasimelteon is a CYP3A4 and CYP1A2 substrate
-
Smokers
- Smoking is a moderate CYP1A2 inducer
- Tasimelteon exposure decreased by ~40% in smokers compared with nonsmokers
-
Strong CYP1A2 Inhibitors
- Avoid coadministration
- Fluvoxamine or other strong CYP1A2 inhibitors may potentially increase tasimelteon exposure and increase risk of adverse reactions
-
Strong CYP3A4 inducers
- Avoid coadministration
- Rifampin or other CYP3A4 inducers may potentially decrease tasimelteon exposure and reduced efficacy
-
Beta-adrenergic receptor antagonists
- Beta-adrenergic receptor antagonists have been shown to reduce production of melatonin via specific inhibition of beta-1 adrenergic receptors
- Nighttime administration of beta-adrenergic receptor antagonists may reduce tasimelteon efficacy
Pregnancy & Lactation
Pregnancy
Available postmarketing case reports use in pregnant females are not sufficient to evaluate drug-associated risk of major birth defects, miscarriage or adverse maternal or fetal outcomes
Animal data
- In pregnant rats, no embryofetal developmental toxicity was observed at exposures of 50 mg/kg/day, or up to 24x higher than the human exposure at the maximum recommended human dose
Lactation
No data available on drug presence or its metabolites in human or animal milk, effects on breastfed infants, effects on milk production
Pregnancy Categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk. C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done. D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk. X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist. NA: Information not available.Pharmacology
Mechanism of Action
Melatonin receptor agonist with high affinity for MT1 and MT2 receptors in the suprachiasmatic nucleus of the brain; MT1 and MT2 are thought to synchronize the body's melatonin and cortisol circadian rhythms with the day-night cycle in patients with non-24-hour disorder
Absorption
Peak plasma concentration: 0.5-3 hr (fasting)
When administered with a high-fat meal, peak plasma concentration was 44% lower than when given in a fasted state, and the median peak concentration was delayed by approximately 1.75 hr
Oral bioavailability: 38.3%
Distribution
Protein bound: 96%
Vd: 59-126 L
Metabolism
Extensively metabolized primarily by oxidation at multiple sites and oxidative dealkylation resulting in opening of the dihydrofuran ring followed by further oxidation to give a carboxylic acid
CYP1A2 and CYP3A4 are the major isozymes involved
Phenolic glucuronidation is the major phase II metabolic route
Major metabolites had 13-fold or less activity at melatonin receptors compared to tasimelteon
Elimination
Half-life: 1.3 hr; 1.3-3.7 hr (metabolites)
Excretion: 80% urine (<1% as parent compound); 4% feces
Administration
Oral Administration
All formulations
- Administer without food
- If unable to take dose at approximately the same time on a given night, skip that dose and take next dose as scheduled
Capsules
- Swallow capsules whole
Oral suspension
- Shake well for at least 30 seconds before administration
- Remove seal and insert press-in bottle adapter (included in packaging) until tightly sealed
- Turn upside down and withdraw prescribed dose with oral syringe
Storage
Capsules
- Store at room temperature, 20-25ºC (68-77ºF), excursions permitted to 15-30ºC (59-86ºF)
- Protect from exposure to light and moisture
Oral suspension
- Unopened bottle: Refrigerate at 5ºC (41ºF), excursions permitted to 2-8ºC (36-46ºF)
Opened bottle
- Refrigerate at 5ºC (41ºF), excursions permitted to 2-8ºC (36-46ºF)
- After opening, discard after 5 weeks (for 48-mL bottle) and after 8 weeks (for 158-mL bottle)
Images
BRAND | FORM. | UNIT PRICE | PILL IMAGE |
---|---|---|---|
tasimelteon oral - | 20 mg capsule | ![]() | |
tasimelteon oral - | 20 mg capsule | ![]() |
Copyright © 2010 First DataBank, Inc.
Patient Handout
tasimelteon oral
TASIMELTEON - ORAL
(TAS-i-MEL-tee-on)
COMMON BRAND NAME(S): Hetlioz
USES: Tasimelteon is used to treat certain sleep disorders (non-24-hour sleep-wake disorder, sleep disturbances in Smith-Magenis Syndrome). It works like a natural substance called melatonin that your body produces. It helps to control your sleep-wake cycle (circadian rhythm). Tasimelteon may improve your ability to sleep at night and to be more active during the day.
HOW TO USE: Take this medication by mouth on an empty stomach as directed by your doctor, usually one hour before bedtime, at the same time every night. The dosage is based on your medical condition and response to treatment. Children's dose is also based on weight. If you are using the capsule form, swallow the capsules whole.If you are using the liquid form of this medication, read the Instructions for Use Leaflet if available from your pharmacist before you start using tasimelteon suspension and each time you get a refill. Shake the bottle well for at least 30 seconds before each dose. Carefully measure the dose using a special measuring device/spoon. Do not use a household spoon because you may not get the correct dose. If you have any questions, ask your doctor or pharmacist.It is very important to take this medication at the same time each night so that you can form a normal sleep-wake cycle. See also Missed Dose section.It may take up to several months before you get the full benefit of this drug.Tell your doctor if your condition does not get better or if it gets worse.
SIDE EFFECTS: Headache, nightmares, or strange dreams may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly. Tasimelteon may also make you drowsy during the day. Talk to your doctor or pharmacist if you have daytime drowsiness.Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.In the US -Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.
PRECAUTIONS: Before taking tasimelteon, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.Before using this medication, tell your doctor or pharmacist your medical history, especially of: liver disease.This drug may make you drowsy. Alcohol or marijuana (cannabis) can make you more drowsy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis).Liquid products may contain sugar and/or aspartame. Caution is advised if you have diabetes, phenylketonuria (PKU), or any other condition that requires you to limit/avoid these substances in your diet. Ask your doctor or pharmacist about using this product safely.Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.It is unknown if this medication passes into breast milk. Consult your doctor before breast-feeding.
DRUG INTERACTIONS: Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.Other medications can affect the removal of tasimelteon from your body, which may affect how tasimelteon works. Examples include ciprofloxacin, fluvoxamine, rifamycins (such as rifabutin), St. John's wort, drugs used to treat seizures (such as carbamazepine, phenytoin), viloxazine, among others.Tell your doctor or pharmacist if you are taking other products that cause drowsiness such as opioid pain or cough relievers (such as codeine, hydrocodone), alcohol, marijuana (cannabis), other drugs for sleep or anxiety (such as alprazolam, lorazepam, zolpidem), muscle relaxants (such as carisoprodol, cyclobenzaprine), or antihistamines (such as cetirizine, diphenhydramine).Check the labels on all your medicines (such as allergy or cough-and-cold products) because they may contain ingredients that cause drowsiness. Ask your pharmacist about using those products safely.Cigarette smoking decreases blood levels of this medication. Tell your doctor if you smoke or if you have recently stopped smoking.
OVERDOSE: If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center.
NOTES: Do not share this medication with others.
MISSED DOSE: If you miss a dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.
STORAGE: Store the capsules at room temperature away from light and moisture. Do not store in the bathroom. Keep all medications away from children and pets.Store the liquid form of this medication in a refrigerator. After opening, discard after 5 weeks (for the 48 milliliter bottle) or after 8 weeks (for the 158 milliliter bottle).Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.
Information last revised March 2022. Copyright(c) 2023 First Databank, Inc.
IMPORTANT: HOW TO USE THIS INFORMATION: This is a summary and does NOT have all possible information about this product. This information does not assure that this product is safe, effective, or appropriate for you. This information is not individual medical advice and does not substitute for the advice of your health care professional. Always ask your health care professional for complete information about this product and your specific health needs.
Formulary
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