Imip

Uses

Diazepam is used for the management of anxiety disorders or for the shortterm relief of the symptoms of anxiety. Anxiety or tension associated with the stress of everyday life usually does not require treatment with an anxiolytic. In acute alcohol withdrawal, Diazepam may be useful in the symptomatic relief of acute agitation, tremor, impending or acute delirium tremens and hallucinosis.

Diazepam is a useful adjunct for the relief of skeletal muscle spasm due to reflex spasm to local pathology (such as inflammation of the muscles or joints, or secondary to trauma), spasticity caused by upper motor neuron disorders (such as cerebral palsy and paraplegia), athetosis, and stiff-man syndrome.

Oral Diazepam may be used adjunctively in convulsive disorders, although it has not proved useful as the sole therapy.

The effectiveness of Diazepam in long-term use, that is, more than 4 months, has not been assessed by systematic clinical studies. The physician should periodically reassess the usefulness of the drug for the individual patient.

Depression: For the relief of symptoms of depression. Endogenous depression is more likely to be alleviated than other depressive states. One to three weeks of treatment may be needed before optimal therapeutic effects are evident.

Childhood Enuresis: May be useful as temporary adjunctive therapy in reducing enuresis in children aged 6 years and older, after possible organic causes have been excluded by appropriate tests. In patients having daytime symptoms of frequency and urgency, examination should include voiding cystourethrography and cystoscopy, as necessary. The effectiveness of treatment may decrease with continued drug administration.

Imip is also used to associated treatment for these conditions: Alcohol Withdrawal Syndrome, Anxiety, Anxiety Disorders, Refractory Epilepsy, Intermittent distinct from a patient’s usual seizure pattern, stereotypic episode Epileptic seizure, Refractory seizure disorders, Skeletal muscle spasm, Sedation, Perioperative management therapyAttention Deficit Hyperactivity Disorder (ADHD), Bulimia Nervosa, Enuresis, Major Depressive Disorder (MDD), Neuropathic Pain, Panic Disorder, Post Traumatic Stress Disorder (PTSD)

How Imip works

Diazepam is a benzodiazepine tranquilliser with anticonvulsant, sedative, muscle relaxant and amnesic properties .

Benzodiazepines, such as diazepam, bind to receptors in various regions of the brain and spinal cord. This binding increases the inhibitory effects of gamma-aminobutyric acid (GABA) . GABAs functions include CNS involvement in sleep induction. Also involved in the control of hypnosis, memory, anxiety, epilepsy and neuronal excitability .

Imipramine works by inhibiting the neuronal reuptake of the neurotransmitters norepinephrine and serotonin . It binds the sodium-dependent serotonin transporter and sodium-dependent norepinephrine transporter reducing the reuptake of norepinephrine and serotonin by neurons. Depression has been linked to a lack of stimulation of the post-synaptic neuron by norepinephrine and serotonin . Slowing the reuptake of these neurotransmitters increases their concentration in the synaptic cleft, producing knock-on effects in protein kinase signalling which is thought to contribute to changes in neurotransmission and brain physiology which relieves symptoms of depression .

Dosage

Imip dosage

Dosage should be individualized for maximum beneficial effect. While the usual daily dosages given below will meet the needs of most patients, there will be some who may require higher doses. In such cases dosage should be increased cautiously to avoid adverse effects.

ADULTS:

Management of Anxiety Disorders and Relief of Symptoms of Anxiety: Depending upon severity of symptoms 2 mg to 10 mg, 2 to 4 times daily

Symptomatic Relief in Acute Alcohol Withdrawal: 10 mg, 3 or 4 times during the first 24 hours, reducing to 5 mg, 3 or 4 times daily as needed

Adjunctively for Relief of Skeletal Muscle Spasm: 2 mg to 10 mg, 3 or 4 times daily

Adjunctively in Convulsive Disorders: 2 mg to 10 mg, 2 to 4 times daily

Geriatric Patients, or in the presence of debilitating disease: 2 mg to 2.5 mg, 1 or 2 times daily initially; increase gradually as needed and tolerated

PEDIATRIC PATIENTS:

Because of varied responses to CNS-acting drugs, initiate therapy with lowest dose and increase as required. Not for use in pediatric patients under 6 months: 1 mg to 2.5 mg, 3 or 4 times daily initially; increase gradually as needed and tolerated

Depression: Initially up to 75 mg daily in divided doses increased gradually to 150-200 mg (up to 300 mg in hospital); up to 150 mg may be given as a single dose at bed time; elderly, initially 10 mg daily, increased gradually to 30-50 mg daily; child not recommended for depression.

Panic attack: Initially 10-25 mg/day, depending on how the medication is tolerated, raise the dose until the desired response is obtained. The daily doses required vary greatly from patient to patient, between 75-150 mg, if necessary it can be increased to 200 mg.Nocturnal enuresis(Child):

• 7 years: 25 mg
• 8 to 11 years: 20-50 mg
• Over 11 years: 50-75 mg at bedtime; max. period of treatment (Including gradual withdrawal) is 3 months; full physical examination is required before further course.

Side Effects

Drowsiness and light headedness the next day; confusion and ataxia (specially in the elderly); amnesia may occur; dependence; paradoxical increase in aggression; occasionally headache, vertigo, hypotension, gastrointestinal disturbances, visual disturbances, dysarthria, tremor, changes in libido, incontinence, urinary retention, blood disorders and jaundice reported.

Dry mouth, less sedation, blurred vision (disturbances of accommodation, increased intraocular pressure), constipation, nausea, difficulty with micturation; cardiovascular side-effects, sweating, tremors, rashes and hypersensitivity reaction (including urticaria & photosensitivity), behavioral disturbances (particularly in children) hypomania or mania (particularly in elderly), interference with sexual function; blood sugar changes, increased appetite, weight gain (occasionally weight loss).

Toxicity

The symptoms of diazepam overdose are mainly an intensification of the therapeutic effects (ataxia, drowsiness, dysarthria, sedation, muscle weakness, profound sleep, hypotension, bradycardia, nystagmus) or paradoxical excitation . In most cases only observation of vital functions is required .

Extreme overdosage may lead to coma, areflexia, cardio-respiratory depression and apnoea, requiring appropriate countermeasures (ventilation, cardiovascular support) .

Benzodiazepine respiratory depressant effects are more serious in patients with severe chronic obstructive airways disease . Severe effects in overdose also include rhabdomyolysis and hypothermia . Overdose of benzodiazepines in combination with other CNS depressants (including alcohol) may be fatal and should be closely monitored .

In general, the use of diazepam in women of childbearing potential, and more specifically during known pregnancy, should be considered only when the clinical situation warrants the risk to the fetus . The possibility that a woman of childbearing potential may be pregnant at the time of institution of therapy should be considered . If this drug is used during pregnancy, or if the patient becomes pregnant while taking this drug, the patient should be apprised of the potential hazard to the fetus . Patients should also be advised that if they become pregnant during therapy or intend to become pregnant they should communicate with their physician about the desirability of discontinuing the drug .

Special care must be taken when diazepam is used during labor and delivery, as high single doses may produce irregularities in the fetal heart rate and hypotonia, poor sucking, hypothermia, and moderate respiratory depression in the neonates . With newborn infants it must be remembered that the enzyme system involved in the breakdown of the drug is not yet fully developed (especially in premature infants) .

Diazepam passes into breast milk . Breastfeeding is therefore not recommended in patients receiving diazepam .

Safety and effectiveness in pediatric patients below the age of 6 months have not been established .

In elderly patients, it is recommended that the dosage be limited to the smallest effective amount to preclude the development of ataxia or oversedation (2 mg to 2.5 mg once or twice daily, initially to be increased gradually as needed and tolerated) . Extensive accumulation of diazepam and its major metabolite, desmethyldiazepam, has been noted following chronic administration of diazepam in healthy elderly male subjects. Metabolites of this drug are known to be substantially excreted by the kidney, and the risk of toxic reactions may be greater in patients with impaired renal function . Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function .

Decreases in clearance and protein binding, and increases in volume of distribution and half-life has been reported in patients with cirrhosis . In such patients, a 2- to 5- fold increase in mean half-life has been reported . Delayed elimination has also been reported for the active metabolite desmethyldiazepam . Benzodiazepines are commonly implicated in hepatic encephalopathy . Increases in half-life have also been reported in hepatic fibrosis and in both acute and chronic hepatitis .

The anticholinergic actvity of imipramine can produce dry mucous membranes, blurred vision, increased intraocular pressure, hyperthermia, constipation, adynamic ileus, urinary retention, delayed micturition, and dilation of the urinary tract .

Central nervous system and neuromuscular effects include drowsiness, lethargy, fatigue, agitation, excitement, nightmares, restlessness, insomnia, confusion, disturbed concentration, disorientation, delusions, and hallucinations.

Effects on the GI tract include anorexia, nausea and vomiting, diarrhea, abdominal cramps, increases in pancreatic enzymes, epigastric distress, stomatitis, peculiar taste, and black tongue.

Rarely agranulocytosis, thrombocytopenia, eosinophilia, leukopenia, and purpura have occured.

Infants whose mothers were receiving tricyclic antidepressants prior to delivery have experienced cardiac problems, irritability, respiratory distress, muscle spasms, seizures, and urinary retention.

Serotonin syndrome can occur when used in conjunction with other pro-serotonergic drugs.

LD₅₀/> Values

Rat - Oral 250 mg/kg - Intraperitoneal 79mg/kg - Subcutaneous 250 mg/kg - Intravenous 15.9 mg/kg

Mouse - Oral 188 mg/kg - Intraperitoneal 51.6 mg/kg - Subcutaneous 195 μg/kg - Intravenous 21 mg/kg

Human range of toxicity is considered to include single dosages greater than 5 mg/kg.

Precaution

Diazepam is not recommended for use in patients with depressive disorders or psychosis. Patients should be advised against the concurrent use of alcohol and other CNS depressant drugs. Patients with known or presumed dependence from alcohol or drugs should not take benzodiazepines.

Since Diazepam has a CNS depressant effect, patients should be warned against driving, operating dangerous machinery, or engaging in other hazardous activities requiring mental alertness and physical coordination.

Cardiac diseases (particularly with arrhythmias), history with epilepsy, pregnancy and breast feeding, elderly, hepatic impairment (avoid if severe), thyroid disease, psychoses, angle-closure glaucoma, history of urinary retention, concurrent electro-convulsive therapy. Drowsiness may affect performances of skilled tasks (e.g. driving), alcohol induced Imipramine effect.

Interaction

Diazepam may potentiate or interact with the effects of other CNS acting drugs such as alcohol, narcotics, hypnotics, sedative antihistamines, antipsychotics, anxiolytics/ sedatives, anesthetics, antidepressants and anticonvulsants. Besides these diazepam may interact with phenytoin, cimetidine, levodopa, lithium.

Imipramine should not be used in combination with Monoamine oxidase inhibitors (MAO), anticholinergic agents, antihypertensive agents, methylphenidate, levodopa, antipsychotic drug, cimetidine, barbiturates, and oral contraceptives.

Volume of Distribution

In young healthy males, the volume of distribution at steady-state is 0.8 to 1.0 L/kg .

Imipramine has a high apparent volume of distribution of 10-20 L/kg . The drug is known to accumulate in the brain at concentrations 30-40 times that in systemic circulation.

Elimination Route

After oral administration, it is considered that diazepam is rapidly and completely absorbed from the gastrointestinal tract as >90% of diazepam is absorbed and the average time to achieve peak plasma concentrations is 1 – 1.5 hours with a range of 0.25 to 2.5 hours .

Absorption is delayed and decreased when administered with a moderate fat meal . In the presence of food mean lag times are approximately 45 minutes as compared with 15 minutes when fasting . There is also an increase in the average time to achieve peak concentrations to about 2.5 hours in the presence of food as compared with 1.25 hours when fasting . This results in an average decrease in Cmax of 20% in addition to a 27% decrease in AUC (range 15% to 50%) when administered with food .

Rapidly and well absorbed (>95%) after oral administration . The primary site of absorption is the small intestine as the basic amine groups are ionized in the acidic environment of the stomach, preventing movement across tissues. Bioavailability ranges from 29-77% due to high inter-individual variability. Peak plasma concentration is usually attained 2-6 hours following oral administration. Absorption is unaffected by food.

Half Life

Diazepam has a biphasic half-life with an initial rapid distribution phase followed by a prolonged terminal elimination phase of 1 or 2 days; its action is further prolonged by the even longer half-life of 2-5 days of its principal active metabolite, desmethyldiazepam (nordiazepam), the relative proportion of which increases in the body on long-term administration . The plasma half-life of diazepam is prolonged in neonates, in the elderly, and in patients with kidney or liver disease .

Imipramine has a mean half life of 12 h. Its active metabolite, desipramine has a mean half life of 22.5 h .

Clearance

The clearance of diazepam is 20 to 30 mL/min in young adults .

Imipramine has a mean clearance of 1 L/h/kg. Its active metabolite, desipramine has a mean clearance of 1.8 L/h/kg .

Elimination Route

Diazepam and its metabolites are excreted mainly in the urine, predominantly as their glucuronide conjugates .

Imipramine is primarily excreted in the urine with less than 5% present as the parent compound

Pregnancy & Breastfeeding use

Category D: The use of Diazepam during the first trimester of pregnancy should almost always be avoided as it bears a risk of congenital malformation.

Diazepam has been detected in breast milk. If possible the use of diazepam should be avoided during lactation.

Pregnancy category D. Limited data suggest that imipramine is likely to be excreted in human breast milk. Known risk of damage to fetus.

Contraindication

Patients with known hypersensitivity to benzodiazepines, & myasthenia gravis are contraindicated to diazepam.

Recent myocardial infarction, arrhythmias (particularly heart block), not indicated in manic phase, severe liver disease.

Acute Overdose

Symptoms: Somnolence, ataxia, confusion, dysarthria, little or no resp depression, hypotension, muscular weakness, deep coma, severe depression, diminished reflexes.

Management: Symptomatic and supportive treatment. Empty stomach by vomiting or gastric lavage. Activated charcoal may help reduce absorption. Flumazenil may be used for the complete or partial reversal of the sedative effects but there is a risk of seizure esp in long-term benzodiazepine users and in cyclic antidepressant overdose.

Children have been reported to be more sensitive than adults to an acute overdosage of imipramine. An acute overdose in infants or young children must be considered serious and potentially fatal.

Storage Condition

Store between 15-30°C. Protect from light. Inj: Avoid freezing.

Store in a cool & dry place, protected from light and moisture. Keep all medicines out of the reach of children.

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