Overdose of caffeine may result in epigastric pain, vomiting, diurese, tachycardia or cardiac arrhythmia, CNS stimulation (insomnia, restlessness, excitement, agitation, jitteriness, tremors and convulsions). Contains paracetamol. Care is advised in the administration of paracetamol to patients with severe renal or severe hepatic impairment. The concomitant use with other products containing paracetamol may lead to an overdose. Paracetamol overdose may cause liver failure which may require liver transplant or lead to death. The hazard of overdose is greater in those with non-cirrhotic alcoholic liver disease.

Women who are pregnant. (Phenylephrine has blood vessel constricting effects that could restrict blood supply to the placenta, or cause problems for women with a history of pre-eclampsia. Ask your doctor or pharmacist for advice on how to treat cold and flu symptoms during pregnancy.) If you take Beechams flu plus caplets in the hour before or the six hours after taking colestyramine, the paracetamol is likely to be less effective. This is because colestyramine reduces the absorption of paracetamol from the gut. Unfortunately, there aren't so many own-brand or generic versions of these around, so you'll usually have to pay a premium for them.Concomitant use of phenylephrine hydrochloride may cause an increased risk of ergotism (see Warnings and Precautions). Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Just because a side effect is stated here, it does not mean that all people using this medicine will experience that or any side effect. For the cheapest option, seek out own-brand or generic painkillers. Supermarkets and discount stores are often cheapest, and branded versions can cost nearly five times as much. If you're taking medicines for high blood pressure you shouldn't take Beechams flu plus caplets, because the decongestant may make your blood pressure medicine less effective.

Excessive intake of caffeine (e.g. coffee, tea and some canned drinks) should be avoided while taking this product. It is thought paracetamol reduces fever by affecting an area of the brain that regulates our body temperature (the hypothalamic heat-regulating center). The paracetamol in Beechams powders capsules helps relieve aches, pains, sore throats and fever associated with colds and flu. This product should not be used by patients taking other sympathomimetics (such as decongestants, appetite suppressants and amphetamine-like psychostimulants) (see interactions). Liver damage is possible in adults who have taken 10g or more of paracetamol. Ingestion of 5g or more of paracetamol may lead to liver damage if the patient has risk factors (see below).Beechams flu plus caplets contain three active ingredients, paracetamol (500mg), phenylephrine (5mg) and caffeine (25mg). Here's everything you need to know about Beechams flu caplets, including how they work, who shouldn't use them and the potential side effects: How do Beechams flu plus caplets work?