Composition

Each 5 ml of syrup contains:

• Diphenhydramine HCl B.P……………………………..  6.25 mg
• Ammonium Chloride B.P……………………………….. 60 mg
• Sodium Citrate B.P…………………………………………  25mg
• Menthol USP……………………………………………………0.5 mg(as flavour)

Pharmacological actions:

1. Diphenhydramine is an antihistamine with H1 receptor antagonistic action.
2. It inhibits most responses of smooth muscle to histamine. Histamine is usually released from the mast cells on encounter with antigens.
3. The antihistamine antagonizes the constrictor action of histamines on the respiratory smooth muscle. H1 antagonists also possess antimuscarinic, adrenaline- enhancing and/ or antagonizing, serotoin  antagonizing and local anesthetics effects.
4. H1 antagonists are used for the palliative treatment of allergic reactions.
5. Ammonium Chloride is used as an expectorant due to its irritant action on the gastric mucosa.
6. Sodium citrate renders mucous less viscous and is taken as an expectorant.
7. Menthol has local anaesthetic and counterirritant qualities and is used to reduce throat irritation.

Pharmacokinetics:
Antihistamines are generally readily absorbed from the gastrointestinal tract. They undergo considerable first pass metabolism in the liver. They are bound to plasma proteins and are also well distributed in the Central Nervous System. They induce the hepatic microsomal enzymes and thus facilitate their own elimination.

Ammonium chloride is effectively absorbed from gastrointestinal tract.The Ammonium ion is converted into urea in the liver.
Sodium citrate, after absorption, is metabolized to bicarbonate.
Menthol acts locally and is not absorbed into the bloodstream.

Indications:
Symptomatic relief of cough and reduces bronchial and nasal congestion.It relieves the symptoms of hay fever and other allergic conditions affecting the upper respiratory tract.

Dose:
Children:

• 2 – 5 years: 2.5 to 5ml or as recommended by the Physician.
• 6 – 12 years: 5 to 10ml, 3 to 4 times a day.

Side effects:
The main side effect is sedation, varying from slight drowsiness to deep sleep, and including lassitude, dizziness and inco-ordination.

Other side effects include gastrointestinal disturbances such as nausea, vomiting, diarrhoea or antimuscarinic effects such as blurred vision, difficulty in micturition, dryness of mouth. Paradoxical central nervous system stimulation may occur.

Contra – indications:

• Hypersensitivity to any of the constituents.
• Antihistamines should not be given to premature infants or neonates.
• Ammonium salts are contra-indicated in presence of impaired hepatic or renal function.

Precautions and warnings:
H1 antagonists interfere with skin tests for allergy, and thus they must be withdrawn well before such tests are performed.
The antihistamines enhance the sedative effects of opioid analgesics, alcohol, barbiturates and hypnotics. They should therefore not be taken concurrently.

Storage:
Do not store above 30°C. Store in a dry place. Protect from direct sunlight. Keep all medicines out of reach of children.