By Irfana
B.Sc (Psychiatry Ward)
21 April 2022 -
Medically reviewed by
D. Pharm
Duloxetine and Gabapentin
Table of Contents

What is Duloxetine?

Duloxetine is a Selective and Norepinephrine Reuptake Inhibitor Antidepressant (SSNRI). Duloxetine treats major depressive disorder in adults and general anxiety disorders in adults and children at least seven years old. It is a prescribed medicine. Order Duloxetine online from a certified online pharmacy.

It is also used to treat nerve pain caused by diabetes in adults (diabetic neuropathy) or chronic muscle or joint pain (such as low back and osteoarthritis pain). The brand name of Duloxetine is Cymbalta, Drizalama Sprinkle, Irenka. (Knadler, M.P., Lobo, E., Chappell, J. and Bergstrom, R., 2011)

What is Gabapentin?

Gabapentin is an anti-epileptic drug, also called an anticonvulsant. Gabapentin is used to tackle neuropathic pain (nerve pain) caused by the herpes virus or shingles (herpes zoster). 

Gabapentin is also used in treating Restless Legs Syndrome (RLS) and partial seizures in adults and children aged at least three years old. The brand name of Gabapentin are Gralise, Horizant, Neurontin, Gabarone. (Goa, K.L. and Sorkin, E.M., 1993)

Forms and Strengths


Duloxetine is available in forms and strengths of:

  • Oral delayed-release capsule: Duloxetine is available in delayed-release capsule form as 20mg, 30mg 40mg, and 60mg strengths.


Gabapentin is available in forms and strengths of:

  • Tablets: Gabapentin is available in 300- and 600 mg tablets (Gralise) and 600- and 800 mg tablets (Neurontin or generic Gabapentin.
  • Oral Solution: Gabapentin is available in oral solution which contains 250 mg of Gabapentin per 5 ml (50 mg per ml) Neurontin or generic Gabapentin.
  • Capsules: Gabapentin is available in capsules as 100, 300, and 400 mg gelatin capsules (Neurontin or generic Gabapentin).
  • Gabapentin Enacafrbil: Gabapentin enacarbil is available in 300 and 600 mg extended-release tablets (Horizant).



Dosage of Duloxetine in Oral delayed-release capsule are:

Dosage for anxiety, nerve pain caused by diabetes, fibromyalgia, and depression:


Minimum Dosage: Minimum dosage can range from 30mg once a day for one week to 60mg once a day. However, for nerve pain caused by diabetes and fibromyalgia, the minimum dosage must not exceed 60mg per day.

Maximum Dosage: Maximum dosage can exceed up to 120mg per day and not more than that. However, for nerve pain caused by diabetes and fibromyalgia, the maximum dosage must not exceed 60mg per day.


Minimum Dosage: For children of 7 years or more minimum dosage can range from 30mg once a day for 2 weeks to 60mg

Once a day and for children younger than 7 years, the doctor must determine the use and dose.

Maximum Dosage: For children of 7 years or more maximum dosage can exceed up to 120mg per day and not more than that. For children younger than 7 years, the doctor must determine the use and dose.


Dosage of Gabapentin for Epilepsy, Post Herpetic Neuralgia, Restless leg syndrome (RLS) are:


Minimum Dosage: The initial dose can range from 300mg to 900mg per day.

Maximum Dosage: The maximum dose can range from 1800mg to 3600mg per day.


Minimum dosage: The initial dose for children less than 12 years can range from 10mg to 15mg per day, and for children greater than 12 years, the initial dose can range from 300mg to 900mg per day.

Maximum Dosage: For children under 12 years can range from 20mg to 50mg per day, and for children greater than 12 years, the maximum dose can range from 1800mg to 3600mg per day.


Aim: In this study, the efficacy of Duloxetine and Gabapentin in patients with moderate to severe knee OA was studied by bringing in several patients to get the reports.

Method: In this trial, 150 patients with moderate to severe knee OA were brought in and were randomly allocated to receive Duloxetine 30mg and Gabapentin 300mg all twice a day for 12 weeks. The Pain severity was measured before, 2 weeks, 1 month, and 3 months after intervention using a visual analog scale (VAS) and functional status using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC).

Results: The WOMAC total and its subscale score were lower in Duloxetine compared to Gabapentin in 2 weeks and 1 month after the intervention. However, there were no significant differences at the end of the third month. Both Gabapentin and Duloxetine significantly reduced the pain.

Conclusion: At the end of the trial, both Gabapentin and Duloxetine have similar and acceptable effects in pain reduction and functional improvement in patients with knee OA. The effects of Duloxetine began from the first week, while the effects of Gabapentin began gradually and were best at the end of the third month.

Side Effects

Both Gabapentin and Duloxetine are associated with many side effects ranging from common to severe, and some of the side effects are as listed below:

Some common side-effects of Gabapentin are:

  • Blurred vision
  • Cold or flu symptoms
  • Fever
  • Nausea and vomiting
  • Congestion
  • Constipation
  • Hostility
  • Dry eyes
  • Drowsiness
  • Body aches

Some severe side-effects of Gabapentin are:

  • Chest pain
  • Black tarry stools
  • Loss of memory
  • Swollen glands
  • Depression and mood swings
  • Cough
  • Sore throat
  • Weakness

Some common side-effects of Duloxetine are:

  • Constipation
  • Vomiting
  • Weight loss
  • Loss of appetite
  • Skin rash
  • Nausea
  • Dry mouth
  • Low blood pressure
  • Sleepiness
  • Stomach pain

Some severe side-effects of Duloxetine are:

  • Sexual dysfunction
  • Frequent urination
  • Colitis
  • Liver disease or damage to the individual who mixes the drug with alcohol. 

Can they be taken Together?

Yes, Gabapentin and Duloxetine have no reason to be taken together, so there are no issues if they were to be taken together. Still, Gabapentin and Duloxetine both have side effects that can make you tired and sleepy, and so if an individual is taking them together, they must be aware of the adverse side effects.

Drug Interactions 

Treatment with Duloxetine might occasionally cause the blood sodium level to drop; this condition is known as hyponatremia, and using Duloxetine with Gabapentin can increase that risk. Duloxetine can cause seizures in some patients, which may reduce the effectiveness of drugs used to control seizures, like Gabapentin.

How does it Work in your Body?

Gabapentin: Gabapentin is known to pass through the blood-brain barrier freely and acts on neurotransmitters, and affects chemicals and nerves in the body that are involved in the cause of seizures and various types of pain.

Duloxetine: Duloxetine is known to increase the amount of norepinephrine and serotonin in the small gaps between the neuron for a few microseconds. For the treatment of depression, the actual response by the cell-binding the drug takes 3-6 weeks for full effect. 

Who should not take it?


Gabapentin can cause severe breathing problems, especially if you already suffer from any breathing disorder or use any medication that can make you drowsy or slow your breathing. Then, it is essential to consult your doctor before taking Gabapentin.


A dangerous or adverse reaction could be possible if Duloxetine is taken by an individual who has used an MAO inhibitor such as isocarboxazid, linezolid, methylene blue injection, phenelzine, tranylcypromine, or any others. 


Duloxetine and Gabapentin 

For women who are breastfeeding: This medication might pass into bosom milk. Assuming you take this medication while you breastfeed, your child might have symptoms of the drug. Let your primary care physician know if you wish to breastfeed. You might have to choose whether to breastfeed or take this medication.

When taken with alcohol: There is significant interaction between Cymbalta (Duloxetine) and liquor in people with a background marked by generous liquor admission or misuse. There doesn't give off an impression of being a very remarkable danger with social consumers (although alert is prompted).

However, the response here is that blending liquor and Gabapentin is not intelligent. Liquor is a focal sensory system depressant, which means it dials back relaxation. Gabapentin can say likewise sluggish an individual's relaxing. However, it's not generally medication-related with deadly excess; it is possibly dangerous toasting overabundance while taking Gabapentin.

For women who are pregnant: Duloxetine and Gabapentin are considered class C pregnancy drugs which there are not enough studies and tests done on humans for these medications. It's suggested to consult your doctors before taking this medication.

When taken on an empty stomach: Duloxetine is best endured when taken later a supper. The adequacy of the particular serotonin and norepinephrine reuptake inhibitor energizer duloxetine doesn't vary when patients with sorrow take it on a vacant stomach or following a feast, as indicated by concentrating on outcomes distributed in Clinical Pharmacology in Drug Development. On the other hand, Gabapentin can be taken with or without food.



These are some of the medical conditions to look for before taking Duloxetine:

For people with liver disease: Try not to take this medication if you have a persistent liver infection or cirrhosis of the liver. You might experience difficulty cleaning the medication from your body. This can prompt further liver harm.

For people with kidney disease: Try not to take this medication, assuming you have severe kidney illness or then again in the event that you get dialysis. Your kidneys might experience difficulty eliminating the drug from your body. This could prompt the development of the medication and increase the danger of incidental effects.

For people with diabetes: This medication might influence your glucose levels. Assuming you have diabetes, your PCP might need you to screen your levels all the more intently and may have to change the measurements of your diabetes prescription.

For people with bipolar disorder: This medication might cause mania or hypomania. Assuming that you or somebody in your family has bipolar confusion, tell your primary care physician before beginning Duloxetine.

For people with high blood pressure: This medication might expand your circulatory strain. On the off chance that you, as of now, have hypertension, let your PCP know before beginning duloxetine.


These are some of the medical conditions to look after before taking Gabapentin:

For people with epilepsy: Try not to quit taking Gabapentin suddenly. Doing this can build your danger of having a condition called status epilepticus. This is a health-related crisis during which short or long seizures happen for 30 minutes or more.

For people with kidney problems: Your body treats this medication more leisurely than ordinary. This might make the medication increment to hazardous levels in your body. Converse with your PCP concerning whether this medication is alright for you.


Gabapentin and Duloxetine are both drugs that perform the best in their fields when taken as prescribed by your doctor. There are not many differences between the both of them. In the end, if you experience any types of adverse side effects, it is suggested to consult your doctor, and the medications must be taken just the way it is prescribed.

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