Lonapam0.5 mg

Seizure Disorders

Lonapam is established (FDA-approved) as adjunctive or sole therapy in the management of certain seizure disorders, including Lennox-Gastaut syndrome (petit mal variant), akinetic seizures, myoclonic seizures, and absence seizures (petit mal), particularly when other agents have proven ineffective or are only partially effective.

Panic Disorder

Lonapam is established (FDA-approved) for the treatment of panic disorder, with or without agoraphobia, in adults.

Other/Off-Label Uses

Lonapam is also used off-label, under specialist guidance, for conditions such as certain movement disorders (e.g. restless legs syndrome, akathisia), acute mania or agitation as an adjunct, and short-term management of severe anxiety symptoms; these uses are not FDA-approved indications and evidence is more limited than for the approved uses above.

Not Indicated For

Lonapam is not a first-line or standalone treatment for ordinary, situational anxiety or insomnia, and is not indicated for long-term use as a general sedative given its dependence potential.

Each tablet contains Clonazepam INN as the active pharmaceutical ingredient, commonly available as 0.5 mg, 1 mg, and 2 mg oral tablets; orally disintegrating tablet formulations of Clonazepam also exist in some markets for patients who have difficulty swallowing.

Lonapam is a long-acting benzodiazepine derivative used to control certain seizure disorders and to treat panic disorder. It works by enhancing the effect of gamma-aminobutyric acid (GABA), the brain's principal inhibitory neurotransmitter, which produces anticonvulsant, anxiolytic, sedative, and muscle-relaxant effects. Lonapam is taken by mouth, usually starting at a low dose that is gradually adjusted by a physician to the lowest amount that controls symptoms with the fewest side effects. Because Lonapam is a controlled substance with recognized potential for abuse, misuse, addiction, and physical dependence, it must be used strictly as prescribed and never stopped abruptly after regular use, since doing so can trigger serious withdrawal effects including seizures.

Benzodiazepine (Anticonvulsant / Anxiolytic)

Mechanism: Clonazepam is a benzodiazepine that binds to a specific site on the GABA-A receptor complex in the central nervous system, distinct from the GABA binding site itself. This binding increases the frequency of chloride-channel opening in response to GABA, potentiating GABA's inhibitory effect on neuronal excitability. The resulting widespread CNS depression produces anticonvulsant, sedative, muscle-relaxant, and anxiolytic effects, and Clonazepam rapidly suppresses the spike-and-wave discharge characteristic of absence seizures as well as other paroxysmal EEG abnormalities.

Pharmacokinetics: Clonazepam is well absorbed after oral administration, with bioavailability of approximately 90%, and is extensively bound to plasma proteins (roughly 85%). It is almost completely metabolized in the liver, mainly via the CYP3A4 enzyme pathway, to largely inactive metabolites that are excreted in the urine. Clonazepam has a long elimination half-life of approximately 30-40 hours, supporting once- to thrice-daily dosing and allowing steady plasma levels to build up over about a week of regular use.

• Take Lonapam by mouth exactly as prescribed, at evenly spaced times each day.
• Lonapam may be taken with or without food.
• Swallow standard tablets with water; if an orally disintegrating formulation of Lonapam is prescribed, follow the specific instructions for placing it on the tongue with dry hands.
• Do not increase the dose of Lonapam or take it more often than prescribed, even if symptoms persist; contact the prescribing physician instead.
• Never stop taking Lonapam suddenly on your own after regular use; it must be tapered off gradually under medical supervision (see Precautions and Warnings).
• If a dose of Lonapam is missed, take it as soon as remembered unless it is close to the time of the next dose; do not double the dose.

• Opioids: concomitant use of Lonapam with opioid analgesics or cough suppressants can cause profound sedation, respiratory depression, coma, and death; this combination should be reserved for patients with no alternative treatment options, at the lowest effective doses for the shortest duration, with close monitoring.
• Alcohol and other CNS depressants (e.g., barbiturates, sedating antihistamines, other benzodiazepines, some antipsychotics and antidepressants): combining these with Lonapam produces additive central nervous system depression, increasing the risk of excessive sedation, impaired coordination, and respiratory depression.
• Strong CYP3A4 inducers (e.g., carbamazepine, phenytoin, phenobarbital, rifampin): these can substantially lower Lonapam blood levels (by roughly a third or more), potentially reducing seizure or panic control.
• Strong CYP3A4 inhibitors (e.g., fluconazole, ketoconazole, ritonavir): these can raise Lonapam blood levels, increasing the risk of excessive sedation and other adverse effects.
• Other anticonvulsants (e.g., valproate): combined use has rarely been associated with absence-seizure status in patients with prior mixed seizure disorders; such combinations should be monitored closely by the treating physician.

Common Side Effects

• Drowsiness (reported in roughly half of patients)
• Ataxia/unsteadiness (reported in roughly a third of patients)
• Dizziness and fatigue
• Abnormal eye movements (nystagmus) and blurred vision
• Slurred speech (dysarthria) and tremor
• Behavioral changes, irritability, or confusion

Less Common but Serious Side Effects (Seek Medical Attention)

• Paradoxical reactions such as increased agitation, aggression, hallucinations, or unusual excitement, more frequent in children and the elderly
• Marked respiratory depression or breathing difficulty, especially with other CNS depressants (see Interaction)
• Signs of physical dependence and withdrawal, including seizures, on abrupt discontinuation after prolonged use (see Precautions and Warnings)
• New or worsening depression, or thoughts of self-harm/suicide
• Severe allergic reaction: rash, swelling of the face or throat, severe dizziness, trouble breathing
• Memory problems (anterograde amnesia)

Pregnancy

Lonapam should be used during pregnancy only if clearly needed and the potential benefit to the mother justifies the potential risk to the fetus, and only under a physician's guidance. Benzodiazepines as a class, including Lonapam, have been associated with a modest teratogenicity signal in some studies, and animal reproduction studies with Lonapam have shown fetal malformations at doses comparable to those used in humans. Use of Lonapam late in pregnancy or near delivery can cause neonatal sedation ("floppy infant" effects) and, with regular use, neonatal withdrawal symptoms after birth; infants exposed to Lonapam in utero should be monitored accordingly.

Breastfeeding

Lonapam passes into breast milk. Breastfeeding is generally not recommended during Lonapam treatment because of the risk of sedation, poor feeding, and accumulation of the drug in the nursing infant; if a mother must continue Lonapam, this should only be done after consulting a physician, with close monitoring of the infant for drowsiness or feeding difficulty.

• Concomitant use with opioids: using Lonapam together with opioids can result in profound sedation, respiratory depression, coma, and death; reserve concomitant prescribing for patients without alternative options and monitor closely (see Interaction).
• Abuse, misuse, and addiction: Lonapam is a controlled substance with a recognized risk of abuse, misuse, and addiction, which can lead to overdose or death; assess each patient's risk before prescribing and monitor throughout treatment.
• Dependence and withdrawal: physical dependence can develop with regular use, and abrupt discontinuation or rapid dose reduction after prolonged use can precipitate acute withdrawal, including seizures, which can be life-threatening; Lonapam must always be tapered off gradually under medical supervision.
• CNS depression: Lonapam commonly causes drowsiness and impaired coordination; patients should not drive, operate machinery, or perform hazardous tasks until they know how Lonapam affects them, and should avoid alcohol and other sedating medicines (see Interaction).
• Paradoxical reactions: some patients, particularly children and the elderly, may experience increased agitation, aggression, or excitement instead of sedation; Lonapam should be discontinued if this occurs.
• Hepatic impairment: because Lonapam is extensively metabolized by the liver, patients with hepatic impairment may have prolonged drug effects and require a lower dose with careful monitoring.
• Elderly patients: older adults are more sensitive to the sedative and coordination-impairing effects of Lonapam, with an increased risk of falls and fractures; a lower starting dose is advised.
• Depression and suicide risk: like other antiepileptic and CNS-depressant drugs, Lonapam may be associated with an increased risk of suicidal thoughts or behavior; monitor for mood changes.

Signs of Lonapam overdose can include marked drowsiness progressing to confusion, impaired coordination, diminished reflexes, coma, and respiratory depression, particularly if taken with alcohol or other CNS depressants. An overdose of Lonapam is a medical emergency. If overdose is suspected, seek immediate emergency medical attention or contact a poison control center right away; do not attempt to manage a suspected overdose at home. Treatment is supportive and provided in a medical facility, with close monitoring of breathing and cardiovascular status; a specific benzodiazepine antagonist may be considered by treating physicians in select cases but carries its own risks, including precipitating seizures in patients dependent on benzodiazepines.

Store at room temperature (below 30°C), away from light and moisture. Keep out of reach of children.

• Hepatic impairment: Lonapam is extensively metabolized by the liver; patients with hepatic impairment should receive a lower dose with careful titration and monitoring, and Lonapam is contraindicated in significant liver disease (see Contraindications).
• Renal impairment: specific dose adjustment guidance is limited, but caution and monitoring are advised, since metabolites are renally excreted.
• Elderly patients: older adults are more sensitive to sedation, dizziness, and impaired coordination with Lonapam, with higher fall risk; a lower starting dose and slower titration are advisable.
• Pregnant and breastfeeding women: see Pregnancy and Lactation for detailed guidance.
• Pediatric patients: use for seizure disorders follows weight-based dosing under specialist supervision; safety and efficacy for panic disorder have not been established in patients under 18 years (see Pediatric Uses).
• Patients with respiratory disease: use with caution in those with compromised respiratory function, given the risk of further respiratory depression.

The duration of Lonapam treatment is individualized by the prescribing physician based on the indication and the patient's response. For seizure disorders, Lonapam may be used long-term with periodic reassessment of continued benefit, seizure control, and side effects. For panic disorder, Lonapam is typically used for a defined trial period with periodic reassessment, since long-term benzodiazepine use carries dependence risk; many prescribers periodically attempt gradual dose reduction to determine if continued treatment is still needed. Whenever Lonapam is stopped, the dose must be tapered down gradually rather than discontinued abruptly (see Precautions and Warnings).

Benzodiazepine; Anticonvulsant; Anxiolytic

Clonazepam binds to a specific benzodiazepine recognition site on the GABA-A receptor-chloride ionophore complex in the central nervous system, distinct from the GABA binding site. This binding enhances the affinity of the receptor for GABA and increases the frequency of GABA-mediated chloride channel opening, producing neuronal hyperpolarization and reduced neuronal excitability. This action raises the seizure threshold and dampens the spread of seizure activity, while also producing anxiolytic, sedative, and muscle-relaxant effects throughout the central nervous system.

D

For seizure disorders (Lennox-Gastaut syndrome, akinetic and myoclonic seizures), Lonapam is used in pediatric patients with dosing individualized by body weight, starting at 0.01-0.03 mg/kg/day (not exceeding 0.05 mg/kg/day) in 2-3 divided doses and increased gradually, as in adults, to a target maintenance range under close physician supervision. Children may be more susceptible to paradoxical excitation, behavioral changes, and increased salivary and bronchial secretions with Lonapam, and should be monitored closely. Safety and efficacy of Lonapam for panic disorder have not been established in patients younger than 18 years, and it should not be used for this indication in children. As in adults, Lonapam must never be stopped abruptly in a child who has been taking it regularly, because of the risk of withdrawal symptoms including seizures.