Instavil 22.75mg Injection is an antiallergic medication. It is used to treats symptoms of allergic conditions caused by insect bites/stings, certain medicines, or hives (rashes, swelling, etc.). Instavil 22.75mg Injection is given as an injection into veins or muscles under the supervision of a doctor. It should be taken as your doctor's advice. The dose and how often you take it depends on what you are taking it for. Your doctor will decide how much you need to improve your symptoms. You should take this medicine for as long as it is prescribed for you. Sleepiness is the most common side effect of this medicine. Avoid driving or attention-seeking activity. If these bother you or appear serious, let your doctor know. There may be ways of reducing or preventing them. In some cases, it may cause dry mouth, so it is advised to drink more water, always carry sugar candy or maintain oral hygiene. Before taking this medicine, let your doctor know if you have glaucoma or have asthma issues, or have high blood pressure. Inform your doctor if you are pregnant, or breastfeeding. Your doctor should also know about all other medicines you are taking as many of these may make this medicine less effective or change the way it works. Generally, it is advised to avoid alcohol while on treatment.