"extreme side effects" is a correct and usable phrase in written English.
You can use it when describing the potential health risks of a medication, for example: "The most common side effects of this medication are mild headaches and nausea, but some patients have reported extreme side effects, such as dizziness and fatigue."
Calomel, blue mass (a mixture of mercury, honey and marshmallow plant), strychnine, castor oil, turpentine, silver nitrate and ipecac were popular treatments for dysentery and diarrhea, but they all had extreme side effects.
You take an aspirin, I take an aspirin, it might give you extreme side effects of illness and your body... may reject it, where I would be fine.
They would also, ideally, have less extreme side effects similar in nature to psychosis, such as dissociation and euphoria, which would in turn reduce the drug's vulnerability to abuse.
Extreme side effects of radiotherapy, including an increased cancer risk after radiation, were observed in patients with inherited disorders such as ataxia-telangiectasia and Nijmegen syndrome [ 16].
Stop exercising immediately if you feel extra pain, discomfort, dizziness, nausea or other extreme side effects.
Both systems, absolute hierarchy and no hierarchy whatsoever, in their extreme, have side effects that hamper the effectiveness of organizations.
Effects of chewing the leaves of the khat plant include euphoria and extreme talkativeness, but side effects can include dizziness, heart problems and anxiety.
Others say they did, but at an extreme cost, including acute side effects, crippling dependency or addiction.
"And that was pretty much it," said Mr. Connolly, spreading his fingers wide as he spoke of his life after Amiodarone, a drug as notorious for side effects like extreme sleeplessness as for its benefits in treating arrhythmia.
"I wouldn't automatically discourage people from doing more if they really want to" and are not experiencing side effects, like extreme fatigue or repeated injuries, Dr. O'Keefe continued.
So, a tasty treat is far better than a nasty pill with major emotional side effects including extreme fear and anxiety (and there also may have been significant physical side effects as many drugs have pages of negative side effects associated with them).
