Diclofenac

Diclofenac - Use | Dosage | Side Effects

Diclofenac is a drug from the group of non-steroidal anti-inflammatory drugs (NSAIDs). It works by inhibiting lipoxygenase, tromboxane-prostanoid receptors and N-methyl-D-aspartate receptor (NMDA).1 Inhibition of these molecules leads to an analgesic, antipyretic and anti-inflammatory effects of this drug. It belongs to one of the most commonly prescribed analgesics worldwide, because it is an effective painkiller while stomach upset is less common than with other NSAIDs.

Contraindications and precautions

Diclofenac is contraindicated in the following situations:

  • In patients allergic to any drug from the group of NSAIDs
  • In patients who have or have ever had a peptic ulcer
  • In patients who have gastrointestinal bleeding
  • In patients with porphyria
  • In pregnant women and nursing mothers

Diclofenac should be taken with extra precaution in the following conditions:

  • If you suffer from bronchial asthma
  • If you have heart problems
  • If you have severe liver damage
  • If you have a blood clotting disorders
  • If you have severe kidney impairment
  • If you are over 65 years old

Diclofenac, pregnancy and lactation

In one prospective study involving 145 pregnant women who took this drug during the first three months of pregnancy an increased risk of fetal malformations was not established, which means that this drug is relatively safe for application during the first trimester.2 Use of this drug during the second trimester can lead to a reduction in birthweight, while its use during the last trimester can cause vaginal bleeding.3 Therefore, Diclofenac should not be used during the second and third trimester of pregnancy.

Diclofenac is excreted in breast milk, and should be avoided during breastfeeding.

Dosage

The usual dosage for Diclofenac immediate-release tablets is 50 mg, 2-3 times a day. The maximum daily dose is 150 mg.

The usual dose for Diclofenac extended-release tablets is 100 mg once a day.

Swallow the tablet whole with sufficient fluid.

It is desirable to take the tablets after meals to reduce stomach upset.

Interactions

Diclofenac must not be used in combination with the following drugs:

  • Methotrexate (a drug used to treat breast cancer). Diclofenac increases the toxicity of this drug.
  • Cyclosporin (immunosuppressive drug). Diclofenac increases the toxicity of this drug.
  • Quinolone antibiotics, such as: Co-administration of these drugs with Diclofenac increases the risk of convulsions.
  • Anti-hypertensive drugs. Diclofenac may reduce the efficacy of these drugs.
  • Lithium (a drug used to treat psychiatric disorders). Diclofenac increases the toxicity of this drug.
  • Digoxin (a cardiac glycoside used in the treatment of heart failure). Diclofenac increases the toxicity of this drug.
  • Concomitant use with other NSAIDs increases the risk of bleeding in the digestive tract.
  • Leflunomide and teriflunomide
  • Tacrolimus

Adverse effects

Diclofenac may cause the following adverse effects:

  • Digestive disorders (abdominal pain, indigestion, heartburn, bloating and bleeding in the stomach). If you notice gastrointestinal bleeding (e.g. black stool), contact your physician immediately.
  • Impaired liver function
  • Blurred vision
  • Double vision
  • Anemia
  • Presence of blood in urine
  • Renal function impairment
  • Vasculitis
  • Bronchospasm
  • Memory loss
  • Disorientation
  • Impotence
  • Pancreatitis
  • Inflammation of the tongue
  • Allergy

References

  1. NCBI link 1
  2. NCBI link 2
  3. NCBI link 3