Pregesic

Description

Pregesic Tablets

 

Orphenadrine Citrate 35mg plus

Paracetamol 450mg

 

Each film coated tablet contains:

Orphenadrine Citrate BP    35mg plus

Paracetamol                  BP   450mg

Excipients                                      q.s.

Colour : Titanium Dioxide BP

 

Category:  Orphenadrine-Anti-cholinergic, Paracetamol-Analgesic and antipyretic

 

PHARMACOLOGY: Orphenadrine is a skeletal muscle relaxant. Paracetamol is an analgesic  and antipyretic

 

PHARMACODYNAMIC:

Mechanism of action: Action of Pregesic Tablets through Orphenadrine: Orphenadrine also possesses anti-cholinergic actions and this acts by blocking the effect of acetylcholine in the central nervous system.

 

Action of Pregesic Tablets through Paracetamol: Paracetamol acts by inhibiting prostaglandin synthesis in the CNS. Thos explains its antipyretic and analgesic properties. It has less effect on cyclooxygenase in peripheral tissue, which accounts for its weak anti-inflammatory activity.

 

Pharmacokinetics:

Absorption: Orphenadrine is readily absorbed from the gastrointestinal tract and is almost completely metabolized. Duration of action is about 4-6 hrs in the recommended dose. The half-life is approximately 14 hrs for the parent frug, and 2-5 hrs for metabolites.

Paracetamol is readily absorbed from the gastrointestinal tract after oral administration.

 

Distribution: Orphenadrine- Peak plasma levels occur 2hrs after oral administration. In animals, distribution is detected in all organs, especially those with greatest perfusion (e.g, lungs). Orphenadrine may cross the placenta; not known whether distributed into milk.

Paracetamol-peak plasma concentrations occur about 10-60 minutes. Paracetamol is distributed into most body tissues. It crosses the placenta and is present in breast milk. Plasma-protein binding is negligible at usual therapeutic concentrations but increases with increasing concentrations.

 

Metabolism: Orphenadrine – Almost completely metabolized to at least 8 metabolites; however, metabolic fate not fully determined.

Paracetamol- It is metabolized in the liver. A minor hydroxylated metabolite which is usually produced in very small amounts by mixed-function oxidases in the liver and which is usually detoxified by conjugation with liver glutathione may accumulate following paracetamol over dosage and cause tissue damage.

 

Elimination: Orphenadrine – Eliminated principally in urine as metabolized and, in small amounts, as unchanged drug.

Paracetamol – It is excreted in the urine, mainly as the glucuronide and sulphate conjugates. The elimination half-life varies from about1 to 4 hours.

 

INDICATIONS: Tension headache, occipital headache associated with spasm of skeletal muscles in the region of the head and neck. Acute and traumatic conditions of the trunk: sprains, whiplash injuries, acute torticolis, prolapsed intervertebral disc.

 

DOSAGE AND ADMINISTRATION:

Adults: The elderly should be advised to take a reduced dosage as they may be more susceptible to anti-cholinergic side effects at regular doses.

Children: Not recommended for children under 12 year of age.

 

CONTRAINDICATIONS: Glaucoma, prostatic hypertrophy or obstruction at the bladder neck, myasthenia gravis, oesophageal spasm and pyloric or duodenal obstruction. Hypersensitivity to paracetamol or Orphenadrine citrate.

 

PRECAUTIONS AND WARNING: Orphanadrine citrate should be used with caution in patients with tachycardia, cardiac decompensation, coronary insufficiency or cardiac arrhythmias. Paracetamol should be used in patients with hepatic or renal dysfunction. Concomitant treatment with other medicines that contain Orphenadrine or paracetamol is not recommended. Safety of continuous long-term therapy with Orphenadrine has not been established. Therefore if Orphenadrine is prescribed for prolong use, periodic monitoring of blood, urine and liver function is recommended.