Sometimes side effects may be more manageable if the dose of a drug is lowered.
However, this depends on the particular drug. With some drugs, lowering the dose too much can make the virus resistant and the drug will lose its effectiveness.
Whether the dose should be lowered is best decided by discussion with your physician. If you are having very severe side effects, it is best to stop the drug altogether and check with your doctor to see if the dose should be changed or your should switch to another drug.
Do not adjust the dose on your own.