Imipramine 50mg Tablets
Overview
What is this medicine?
How to Use This Medicine
To get the most benefit from your medication, it's essential to use it as directed by your doctor. Carefully read all the information provided with your medication and follow the instructions closely. If you experience drowsiness after taking this medication, discuss it with your doctor, as they may need to adjust your dosage or the timing of when you take it. Continue taking your medication as prescribed by your doctor or healthcare provider, even if you're feeling well.
Storing and Disposing of Your Medication
To maintain the effectiveness and safety of your medication, store it at room temperature, protected from light, and in a dry place. Avoid storing it in a bathroom. Keep all medications in a secure location, out of the reach of children and pets. When disposing of unused or expired medications, do not flush them down the toilet or pour them down the drain unless instructed to do so. Instead, consult with your pharmacist for guidance on the best disposal method. You may also want to explore drug take-back programs available in your area.
What to Do If You Miss a Dose
If you miss a dose, take it as soon as you remember. However, if it's close to the time for your next scheduled dose, skip the missed dose and resume your regular dosing schedule. Avoid taking two doses at the same time or taking extra doses. If you take your daily dose at bedtime and miss a dose, do not take the missed dose the next morning.
Lifestyle & Tips
- Avoid alcohol and other CNS depressants (e.g., sedatives, tranquilizers) as they can increase drowsiness and other side effects.
- Be cautious when driving or operating machinery until you know how this medication affects you, as it can cause drowsiness, dizziness, or blurred vision.
- Avoid sudden changes in position (e.g., standing up quickly from a sitting or lying position) to prevent dizziness or fainting due to orthostatic hypotension.
- Protect yourself from the sun, as imipramine can increase sensitivity to sunlight. Use sunscreen and wear protective clothing.
- Maintain good oral hygiene and drink plenty of water to help with dry mouth, a common side effect.
- Do not stop taking this medication suddenly without consulting your doctor, as it can lead to withdrawal symptoms.
Available Forms & Alternatives
Dosing & Administration
Adult Dosing
Condition-Specific Dosing:
Pediatric Dosing
Dose Adjustments
Renal Impairment:
Hepatic Impairment:
Pharmacology
Mechanism of Action
Pharmacokinetics
Absorption:
Distribution:
Elimination:
Pharmacodynamics
Safety & Warnings
BLACK BOX WARNING
Side Effects
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor or seek medical attention immediately:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Signs of high or low blood pressure, including:
+ Severe headache or dizziness
+ Passing out
+ Changes in eyesight
Confusion
Hallucinations (seeing or hearing things that are not there)
Sleep disturbances, including trouble sleeping or bad dreams
Erectile dysfunction or changes in sex interest
Fever, chills, or sore throat
Unexplained bruising or bleeding
Feeling extremely tired or weak
Yellow skin or eyes (jaundice)
Chest pain or pressure
Fast or abnormal heartbeat
Shortness of breath
Sudden weight gain or swelling in the arms or legs
Weakness on one side of the body
Trouble speaking or thinking
Changes in balance
Drooping on one side of the face
Blurred eyesight
Ringing in the ears
Burning, numbness, or tingling sensations
Trouble controlling body movements
Twitching
Seizures
Severe constipation or stomach pain (may indicate a bowel problem)
Trouble passing urine
Swelling
Mouth irritation or mouth sores
Enlarged breasts or nipple discharge
Swelling of the testicles
Hair loss
Monitoring for Blood Sugar Changes
Inform your doctor if you experience any signs of high or low blood sugar, including:
Breath that smells like fruit
Dizziness
Fast breathing
Fast heartbeat
Feeling confused, sleepy, or weak
Flushing
Headache
Unusual thirst or hunger
Passing urine more often
Shaking or sweating
Eye Problems
Some individuals may be at a higher risk of developing eye problems while taking this medication. Your doctor may recommend an eye exam to assess your risk. If you experience any of the following symptoms, contact your doctor immediately:
Eye pain
Changes in eyesight
Swelling or redness in or around the eye
Serotonin Syndrome
A rare but potentially life-threatening condition called serotonin syndrome may occur, especially when taking certain other medications. Seek medical help right away if you experience:
Agitation
Changes in balance
Confusion
Hallucinations
Fever
Fast or abnormal heartbeat
Flushing
Muscle twitching or stiffness
Seizures
Shivering or shaking
Excessive sweating
Severe diarrhea, upset stomach, or vomiting
Severe headache
Other Possible Side Effects
While many people may not experience any side effects or only minor ones, it's essential to be aware of the following potential side effects:
Dizziness
Sleepiness
Fatigue
Weakness
Dry mouth
Constipation
Diarrhea
Stomach pain
Upset stomach
Vomiting
Decreased appetite
Changes in taste
Stomach cramps
Weight gain or loss
Excessive sweating
Flushing
Headache
If you experience any of these side effects or have concerns, contact your doctor or seek medical attention. You can also report side effects to the FDA at 1-800-332-1088 or https://www.fda.gov/medwatch.
Seek Immediate Medical Attention If You Experience:
- Worsening depression or suicidal thoughts/behavior, especially at the beginning of treatment or after a dose change.
- New or worsening anxiety, agitation, panic attacks, insomnia, irritability, hostility, impulsivity, or extreme restlessness.
- Symptoms of serotonin syndrome: agitation, hallucinations, fever, sweating, shivering, fast heart rate, muscle stiffness or twitching, loss of coordination, nausea, vomiting, diarrhea.
- Signs of heart problems: fast or irregular heartbeat, chest pain, shortness of breath, fainting, severe dizziness.
- Seizures.
- Severe anticholinergic effects: severe constipation, difficulty urinating, severe blurred vision, confusion, hallucinations.
- Allergic reaction: rash, itching/swelling (especially of face/tongue/throat), severe dizziness, trouble breathing.
Before Using This Medicine
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the symptoms you experienced.
If you have recently had a heart attack.
If you have taken certain medications for depression or Parkinson's disease within the last 14 days, including isocarboxazid, phenelzine, tranylcypromine, selegiline, or rasagiline, as this may lead to very high blood pressure.
If you are currently taking linezolid or methylene blue, as these medications can interact with this drug.
* If you are breastfeeding, as you should not breastfeed while taking this medication.
This list is not exhaustive, and it is crucial to discuss all your medications (prescription, over-the-counter, natural products, and vitamins) and health issues with your doctor and pharmacist. They will help determine if it is safe for you to take this medication with your other medications and health conditions. Never start, stop, or change the dosage of any medication without first consulting your doctor.
Precautions & Cautions
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication. Your doctor may advise you to stop taking this drug before certain surgical procedures, and will provide guidance on when to resume taking it after the surgery or procedure.
Caution with Daily Activities
Until you understand how this medication affects you, avoid driving and other tasks that require alertness. To minimize the risk of dizziness or fainting, rise slowly from a sitting or lying down position, and exercise caution when climbing stairs.
Discontinuing the Medication
Do not stop taking this medication abruptly without consulting your doctor, as this may increase the risk of side effects. If you need to discontinue the medication, your doctor will provide instructions on how to gradually stop taking it.
Special Considerations
If you have diabetes (high blood sugar), closely monitor your blood sugar levels while taking this medication. Before consuming alcohol, marijuana, or other forms of cannabis, or taking prescription or over-the-counter medications that may cause drowsiness, consult with your doctor.
Potential Side Effects and Interactions
It may take several weeks to experience the full effects of this medication. Be aware that you may be more susceptible to sunburn, so avoid exposure to sunlight, sunlamps, and tanning beds, and use protective measures such as sunscreen, clothing, and eyewear. In hot weather or during physical activity, drink plenty of fluids to prevent dehydration.
Monitoring and Follow-up
Your doctor may require you to undergo an electrocardiogram (ECG) before starting this medication and during treatment. If you are 65 years or older, use this medication with caution, as you may be more prone to side effects.
Pregnancy and Breastfeeding
If you are pregnant or plan to become pregnant, discuss the benefits and risks of taking this medication with your doctor.
Overdose Information
Overdose Symptoms:
- Cardiac arrhythmias (e.g., tachycardia, ventricular fibrillation, asystole)
- Severe hypotension
- Seizures
- Coma
- Respiratory depression
- Dilated pupils
- Hyperthermia
- Agitation, confusion, hallucinations
- Severe anticholinergic effects (e.g., urinary retention, paralytic ileus)
What to Do:
Seek immediate emergency medical attention. Call 911 or your local poison control center (1-800-222-1222 in the US). Treatment is supportive and symptomatic, often involving gastric lavage, activated charcoal, continuous ECG monitoring, and management of arrhythmias, hypotension, and seizures.
Drug Interactions
Contraindicated Interactions
- Monoamine Oxidase Inhibitors (MAOIs) - risk of serotonin syndrome, hypertensive crisis
- Cisapride - risk of QT prolongation and arrhythmias
- Pimozide - risk of QT prolongation and arrhythmias
Major Interactions
- Other QT-prolonging drugs (e.g., antiarrhythmics like quinidine, procainamide; some antipsychotics like thioridazine, ziprasidone)
- CNS depressants (e.g., alcohol, benzodiazepines, opioids, sedatives) - additive CNS depression
- Sympathomimetics (e.g., epinephrine, norepinephrine, phenylephrine) - potentiated pressor response
- Anticholinergic agents (e.g., atropine, benztropine, antihistamines) - additive anticholinergic effects
- CYP2D6 inhibitors (e.g., fluoxetine, paroxetine, quinidine, cimetidine) - significantly increase imipramine and desipramine plasma levels
- Thyroid hormones - increased risk of cardiac toxicity
Moderate Interactions
- Anticoagulants (e.g., warfarin) - increased risk of bleeding due to inhibition of metabolism
- Antihypertensives (e.g., guanethidine, clonidine) - imipramine may block the antihypertensive effect
- Barbiturates - may decrease imipramine levels due to enzyme induction
- Methylphenidate - may increase imipramine levels
- Oral contraceptives - may increase imipramine levels
Minor Interactions
- Not available
Monitoring
Baseline Monitoring
Rationale: To assess for pre-existing cardiac conduction abnormalities, especially in elderly patients or those with cardiac history, due to risk of QT prolongation and arrhythmias.
Timing: Prior to initiation of therapy
Rationale: Imipramine is extensively metabolized by the liver; to assess baseline hepatic function.
Timing: Prior to initiation of therapy
Rationale: To assess baseline renal function, as metabolites are renally excreted.
Timing: Prior to initiation of therapy
Rationale: To establish baseline and monitor for orthostatic hypotension and tachycardia.
Timing: Prior to initiation of therapy (supine and standing BP)
Rationale: To establish baseline symptom severity and monitor for worsening depression or emergence of suicidal thoughts/behaviors.
Timing: Prior to initiation of therapy
Routine Monitoring
Frequency: Periodically, especially with dose increases, in elderly patients, or those with cardiac risk factors
Target: Normal PR, QRS, and QTc intervals (QTc <450 ms for males, <470 ms for females)
Action Threshold: Significant prolongation of PR, QRS, or QTc interval; new arrhythmias. Consider dose reduction or discontinuation.
Frequency: Regularly, especially during dose titration and in early treatment
Target: Within patient's normal range, without significant orthostatic drop
Action Threshold: Significant orthostatic hypotension (e.g., >20 mmHg systolic drop) or persistent tachycardia. Consider dose reduction or intervention.
Frequency: If poor response, suspected toxicity, or to confirm adherence
Target: Combined imipramine + desipramine plasma levels: 150-300 ng/mL (for depression)
Action Threshold: Levels outside therapeutic range; adjust dose accordingly.
Frequency: Weekly during initial treatment, then periodically
Target: Improvement in target symptoms, absence of suicidal ideation or new/worsening adverse effects
Action Threshold: Worsening depression, emergence of suicidal thoughts/behaviors, significant agitation, or severe adverse effects. Re-evaluate treatment plan.
Frequency: Periodically
Target: Stable weight or within healthy range
Action Threshold: Significant weight gain. Counsel on diet and exercise.
Symptom Monitoring
- Worsening depression
- Emergence of suicidal thoughts or behaviors
- Unusual changes in behavior (e.g., agitation, irritability, anxiety, panic attacks, insomnia, impulsivity, aggression, mania/hypomania)
- Cardiac symptoms (e.g., palpitations, chest pain, dizziness, fainting)
- Anticholinergic effects (e.g., dry mouth, blurred vision, constipation, urinary retention)
- Orthostatic hypotension (dizziness upon standing)
- Seizures
- Symptoms of serotonin syndrome (e.g., agitation, hallucinations, rapid heart beat, fever, overactive reflexes, nausea, vomiting, diarrhea, muscle rigidity, incoordination)
- Allergic reactions (e.g., rash, hives, swelling)
Special Patient Groups
Pregnancy
Category D. Imipramine crosses the placenta. Use during pregnancy is generally not recommended unless the potential benefit outweighs the potential risk to the fetus. Neonates exposed to TCAs in the third trimester may experience withdrawal symptoms (e.g., respiratory distress, cyanosis, apnea, seizures, feeding difficulties, hypotonia, hypertonia, tremor, irritability) and/or anticholinergic effects.
Trimester-Specific Risks:
Lactation
L3 (Moderately Safe). Imipramine and its active metabolite, desipramine, are excreted into breast milk. While levels in breast milk are generally low, potential for adverse effects in the infant exists. Monitor breastfed infants for sedation, poor feeding, irritability, and weight gain. Consider alternative therapies or close monitoring if breastfeeding.
Pediatric Use
Imipramine is FDA approved for nocturnal enuresis in children aged 6 years and older. It is NOT FDA approved for depression in pediatric patients, and carries a Black Box Warning for increased risk of suicidal thoughts and behaviors in children, adolescents, and young adults when used for depression or other psychiatric disorders. Close monitoring is essential if used off-label for depression.
Geriatric Use
Elderly patients are more sensitive to the anticholinergic, sedative, and cardiovascular effects of imipramine (e.g., orthostatic hypotension, tachycardia, arrhythmias, confusion, urinary retention, constipation). Start with lower doses (e.g., 25-50 mg/day) and titrate slowly. Close monitoring for adverse effects is crucial. Consider alternative antidepressants with a more favorable side effect profile.
Clinical Information
Clinical Pearls
- Imipramine has a narrow therapeutic index; therapeutic drug monitoring (TDM) of combined imipramine and desipramine levels can be useful, especially in cases of non-response or suspected toxicity.
- Antidepressant effects typically take 2-4 weeks to manifest, while sedative and anticholinergic side effects may occur sooner.
- Due to its significant anticholinergic properties, imipramine should be used with caution or avoided in patients with benign prostatic hyperplasia, narrow-angle glaucoma, or severe constipation.
- Abrupt discontinuation can lead to withdrawal symptoms (e.g., nausea, vomiting, dizziness, headache, malaise, sleep disturbance, irritability); taper dose gradually.
- Cardiac toxicity, particularly arrhythmias, is a major concern in overdose and requires immediate medical attention.
- Orthostatic hypotension is common, especially at the start of treatment; advise patients to rise slowly from sitting or lying positions.
Alternative Therapies
- Other Tricyclic Antidepressants (TCAs): Amitriptyline, Nortriptyline, Doxepin, Desipramine
- Selective Serotonin Reuptake Inhibitors (SSRIs): Fluoxetine, Sertraline, Escitalopram, Paroxetine, Citalopram
- Serotonin-Norepinephrine Reuptake Inhibitors (SNRIs): Venlafaxine, Duloxetine, Desvenlafaxine
- Atypical Antidepressants: Bupropion, Mirtazapine, Trazodone
- For Nocturnal Enuresis: Desmopressin, Oxybutynin, behavioral therapies (e.g., enuresis alarms)