Linctuses are viscous liquid oral preparations that are prescribed for relief of cough. They contain medicaments that have demulcent or expectorant action. Linctuses should be taken in small doses, sipped and swallowed slowly without diluting with water to have the maximum and prolonged effect of medicament. Linctuses normally do not have any major side effects. In case of overdose, they may cause headache, stomach upset and diarrhea.

Formulation of linctuses requires the following:

1. Vehicles: Simple syrup is commonly used as the vehicle. Syrup tolu is preferred in certain cases because of its aromatic odor and flavor. Moreover, it is believed to have a mild expectorant action.
2. Adjuvants: Commonly used adjuvants in linctuses are as follows:
   1. Chemical stabilizers: The stability of linctuses is due to the presence of the simple syrup as vehicle.
   2. Coloring agents: Coal tar dyes
   3. Flavoring agents: Lemon syrup, black current syrup, oxymel
   4. Preservatives: Syrup has high osmotic pressure, which eliminates additional use of other preservatives.

Example

Codeine linctus BPC

 

	Codeine phosphate	0.3 g
	Lemon syrup	20 ml
	Benzoic acid solution	2 ml
	Chloroform spirit	2 ml
	Compound tartrazine solution	1 ml
	Purified water	2 ml
	Syrup (q.s.)	100 ml

 

Codeine phosphate is dissolved in water. To this, benzoic acid solution, chloroform spirit and compound tartrazine solution are added and mixed well. Then, lemon syrup is added and the volume is made up with syrup.