Products
Diclofenac is commercially available in the form of tablets, capsules, soft capsules (liquid caps), dragées, drops, suppositories, as a solution for injection, gel, patches, and eye drops (Voltaren, generics), among others. The analgesic has been approved in many countries since 1974. This article refers to peroral use. For more information, see also diclofenac gel, diclofenac gel 3%, diclofenac injection, and diclofenac eye drops.
Structure and properties
Diclofenac (C14H11Cl2NO2, Mr = 296.15 g/mol) is present in the medicinal products for ingestion either as diclofenac sodium or diclofenac potassium. They are white to slightly yellowish, crystalline, and slightly hygroscopic powders that are sparingly soluble in water. Within the NSAIDs, diclofenac belongs to the arylacetic acid or phenylacetic acid derivatives.
Effects
Diclofenac (ATC M01AB05) has analgesic, antipyretic, and anti-inflammatory properties. The effects are due to inhibition of the enzyme cyclooxygenase and reduced formation of prostaglandins. Diclofenac has a short half-life of one to three hours and is therefore administered in sustained-release dosage forms.
Indications
For the treatment of pain and inflammatory conditions of various causes, for example, arthritis, osteoarthritis, after surgery and injury, menstrual cramps, migraine, and gout. According to the professional information, fever alone is not an indication.
Dosage
According to the SmPC. The usual maximum daily dose is 100 to 150 mg for adults. In self-medication, a maximum of 75 mg (25 mg 3 times daily) may be administered daily. The drugs are taken before or with meals, depending on the dosage form. If taken with meals, tolerance may be increased, but the effect is less rapid.
Contraindications
- Hypersensitivity (also to other NSAIDs).
- Last third of pregnancy
- Stomach and intestinal ulcers
- Inflammatory bowel disease
- Severe hepatic dysfunction, severe renal insufficiency, severe cardiac insufficiency.
- Pain after coronary bypass surgery.
For complete precautions, see the drug label.
Interactions
Diclofenac is metabolized by CYP2C9. Please refer to the SmPC for comprehensive drug-drug interaction information.
Adverse effects
The most common possible adverse effects include digestive symptoms (such as nausea, vomiting, diarrhea, abdominal pain, bloating), fluid retention and water retention, high blood pressure, rash, headache, dizziness, and lightheadedness. As with all nonsteroidal anti-inflammatory drugs, serious side effects such as gastrointestinal ulcers, liver dysfunction, and renal insufficiency may occur with long-term treatment.
