Doxepin 150mg Capsules

Doxepin is a tricyclic antidepressant (TCA) that primarily inhibits the reuptake of norepinephrine (NE) and serotonin (5-HT) at the presynaptic neuronal membrane, thereby increasing the concentration of these neurotransmitters in the synaptic cleft. It also possesses potent antihistaminic (H1), moderate anticholinergic (muscarinic), and moderate alpha-1 adrenergic receptor blocking properties. Its sedative effects are largely attributed to its potent H1 antagonism, while its antidepressant effects are linked to NE and 5-HT reuptake inhibition.

Urgent Side Effects: Seek Medical Attention Immediately

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 help right away:

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
Fast heartbeat
Difficulty urinating
Feeling extremely nervous or excitable
Fever, chills, or sore throat
Unexplained bruising or bleeding
Feeling very tired or weak
Yellowing of the skin or eyes (jaundice)
Ringing in the ears (tinnitus)
Changes in sex interest
Enlarged breasts or nipple discharge
Swelling of the testicles

Important Warning for Asthma Patients

If you have asthma, use this medication with caution. Worsening of asthma symptoms has been reported in people taking this drug. If your asthma symptoms worsen while taking this medication, contact your doctor immediately.

Other Possible Side Effects

Like all medications, this drug may cause side effects. Many people experience no side effects or only mild ones. However, if you notice any of the following side effects or any other unusual symptoms, contact your doctor or seek medical help:

Feeling dizzy, sleepy, tired, or weak
Constipation, diarrhea, stomach pain, upset stomach, vomiting, or decreased appetite
Dry mouth
Changes in taste
Mouth irritation or mouth sores
Weight gain
Excessive sweating
Flushing
Hair loss
* Headache

This is not an exhaustive list of possible side effects. If you have questions or concerns about side effects, contact your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.

Before Taking This Medication: Important Information to Share with Your Doctor

It is essential to inform your doctor about the following:

Any allergies you have, including allergies to this medication, its components, or other substances. Describe the allergic reaction you experienced, including any symptoms.
Certain health conditions, such as:
+ Difficulty urinating
+ Glaucoma
Current or recent use of specific medications, including:
+ Linezolid or methylene blue
+ Certain antidepressants or Parkinson's disease medications taken within the last 14 days, such as isocarboxazid, phenelzine, tranylcypromine, selegiline, or rasagiline (as this may lead to very high blood pressure)
Use of other medications that can cause drowsiness, as there are many drugs with this potential effect. If you are unsure, consult your doctor or pharmacist.
* 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 problems with your doctor and pharmacist. They will help determine if it is safe to take this medication with your other medications and health conditions. Never start, stop, or change the dose of any medication without first consulting your doctor.

It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication. This will help ensure your safety and prevent potential interactions with other treatments.

Until you know how this medication affects you, avoid driving and other activities that require you to be alert. You may not experience the full effects of the medication for several weeks.

Do not stop taking this medication abruptly without consulting your doctor, as this may increase your risk of side effects. If you need to discontinue the medication, your doctor will instruct you on how to gradually stop taking it to minimize potential risks.

While taking this medication, it is recommended that you avoid consuming alcohol. Additionally, before using marijuana, cannabis products, or prescription or over-the-counter medications that may cause drowsiness, consult with your doctor to discuss potential interactions.

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 eye pain, changes in vision, or swelling and redness in or around the eye, contact your doctor immediately.

This medication may increase your sensitivity to the sun, making you more prone to sunburn. Take necessary precautions when spending time outdoors, and inform your doctor if you experience excessive sunburning while taking this medication.

If you have diabetes, it is crucial to monitor your blood sugar levels closely. Be aware of the signs of high or low blood sugar, which may include fruity breath odor, dizziness, rapid breathing, rapid heartbeat, confusion, drowsiness, weakness, flushing, headache, unusual thirst or hunger, frequent urination, shaking, or sweating. Report any of these symptoms to your doctor.

If you are 65 years or older, use this medication with caution, as you may be more susceptible to side effects.

Some medications, including this one, may affect fertility and the ability to conceive. If you have concerns or questions, discuss them with your doctor.

If you are pregnant or planning to become pregnant, consult with your doctor to weigh the benefits and risks of taking this medication during pregnancy. Taking this medication in the third trimester may pose health risks to the newborn, so it is essential to discuss this with your doctor.

• Monoamine Oxidase Inhibitors (MAOIs) - risk of hyperpyretic crisis, severe convulsions, and death. Allow at least 14 days between discontinuing MAOI and starting doxepin, and vice versa.
• Cisapride - increased risk of QT prolongation and arrhythmias.

• CNS Depressants (e.g., alcohol, benzodiazepines, opioids, sedatives, hypnotics, antihistamines) - additive CNS depression, increased sedation, respiratory depression.
• Anticholinergic Agents (e.g., atropine, benztropine, diphenhydramine, antipsychotics) - additive anticholinergic effects (e.g., severe constipation, urinary retention, blurred vision, delirium).
• Sympathomimetics (e.g., epinephrine, norepinephrine, phenylephrine, pseudoephedrine) - potentiation of cardiovascular effects (hypertension, arrhythmias).
• QT Prolonging Drugs (e.g., antiarrhythmics like quinidine, procainamide; some antipsychotics like thioridazine; some antibiotics like moxifloxacin) - increased risk of QT prolongation and Torsades de Pointes.
• CYP2D6 Inhibitors (e.g., fluoxetine, paroxetine, quinidine, cimetidine) - can significantly increase doxepin and nordoxepin plasma concentrations, leading to increased toxicity.
• Thyroid Hormones - increased risk of cardiac arrhythmias and toxicity.

• CYP1A2 Inhibitors (e.g., fluvoxamine, ciprofloxacin) - may increase doxepin levels.
• CYP2C19 Inhibitors (e.g., omeprazole, fluoxetine) - may increase doxepin levels.
• CYP3A4 Inhibitors (e.g., ketoconazole, ritonavir) - may increase doxepin levels.
• Antihypertensives (especially adrenergic neuron blockers like guanethidine, clonidine) - doxepin may antagonize their hypotensive effects.
• Warfarin - potential for altered anticoagulant effect (monitor INR).

• Tobacco Smoking - may induce CYP1A2, potentially decreasing doxepin levels.
• Grapefruit Juice - theoretical inhibition of CYP3A4, but clinical significance is minor.

• Worsening depression
• Emergence or worsening of suicidal thoughts or behavior
• Unusual changes in behavior (e.g., agitation, irritability, anxiety, panic attacks, insomnia, impulsivity, aggression, mania/hypomania)
• Dry mouth
• Blurred vision
• Constipation
• Urinary retention
• Dizziness or lightheadedness (especially upon standing)
• Sedation or drowsiness
• Confusion or disorientation (especially in elderly)
• Tremor
• Palpitations or irregular heartbeat
• Seizures

Doxepin is Pregnancy Category C. It should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. There are no adequate and well-controlled studies in pregnant women. Neonates exposed to TCAs in the third trimester have developed withdrawal symptoms.

Doxepin and its active metabolite, nordoxepin, are excreted into breast milk. The American Academy of Pediatrics considers doxepin to be a drug for which the effect on the nursing infant is unknown but may be of concern. Use with caution; monitor infant for sedation, poor feeding, and weight gain.

Safety and efficacy have not been established for pediatric patients for depression or anxiety. Doxepin carries a Black Box Warning regarding increased risk of suicidal thinking and behavior in children, adolescents, and young adults (up to age 24) treated with antidepressants. Use in this population is generally not recommended for these indications.

Elderly patients are more sensitive to the anticholinergic, sedative, and hypotensive effects of doxepin. They are at increased risk for falls, cognitive impairment (delirium), and urinary retention. Start with lower doses (e.g., 10-25 mg/day) and titrate slowly. Avoid if possible in patients with dementia or significant cognitive impairment due to anticholinergic burden. Monitor closely for adverse effects.

• Doxepin is highly sedating due to its potent H1 antagonism; therefore, it is often dosed at bedtime, especially for depression/anxiety.
• The 150mg capsule is a high dose, typically reserved for moderate to severe depression or anxiety. Lower doses (e.g., 3-6 mg) are available as a separate formulation (Silenor) specifically for insomnia.
• Significant anticholinergic side effects (dry mouth, constipation, blurred vision, urinary retention) are common, especially at higher doses, and can be particularly problematic in the elderly.
• Due to its cardiac effects (e.g., QT prolongation, orthostatic hypotension), caution is advised in patients with pre-existing cardiac disease. A baseline ECG is recommended, especially in older adults or those with cardiac risk factors.
• Doxepin has a narrow therapeutic index, and overdose can be life-threatening, leading to cardiac arrhythmias, severe CNS depression, and seizures.
• Patients should be warned about the Black Box Warning for suicidality, especially young adults, and monitored closely for worsening mood or behavioral changes.

• Other Tricyclic Antidepressants (TCAs): Amitriptyline, Imipramine, Nortriptyline, Desipramine (differ in side effect profiles and selectivity for NE/5-HT).
• Selective Serotonin Reuptake Inhibitors (SSRIs): Fluoxetine, Sertraline, Paroxetine, Citalopram, Escitalopram (first-line for depression/anxiety, generally better tolerated).
• Serotonin-Norepinephrine Reuptake Inhibitors (SNRIs): Venlafaxine, Duloxetine, Desvenlafaxine.
• Atypical Antidepressants: Bupropion, Mirtazapine, Trazodone.
• For anxiety: Benzodiazepines (short-term), Buspirone, SSRIs/SNRIs.
• For insomnia: Zolpidem, Eszopiclone, Zaleplon, Trazodone, Mirtazapine, Suvorexant, Lemborexant.

If your symptoms or health issues persist or worsen, it is essential to contact your doctor promptly. To ensure safe and effective treatment, never share your medication with others or take someone else's medication. This medication is accompanied by a Medication Guide, which provides crucial information for patients. Please read this guide carefully and review it again whenever you receive a refill of this medication. If you have any questions or concerns about this medication, consult your doctor, pharmacist, or other healthcare provider for guidance. In the event of a suspected overdose, immediately call your local poison control center or seek emergency medical attention. When reporting the incident, be prepared to provide details about the medication taken, the amount consumed, and the time it occurred.