Prescription Medication

You can generally buy medications that are prescribed, over the counter, without a prescription, particularly if you have evidence that you were previously prescribed them regularly.   My wife buys thyroxine, Pregabalin, various anti-biotics without being asked for prescription.

An exception might be medication which is potentially dangerous/addictive, such as morphine.

If a pharmacist declines to sell you the medication, you may be forced to see a doctor - for Ksh 4000 to 6000, to get a repeat prescription, or you try a different pharmacist. 

The issue with the doctor is that s/he will most likely want to 'review' you before writing each repeat prescription - unfortunately it tends to be all about money, rather than patients wellbeing.  So avoid this route if you can.

Be aware that you may have to settle for generic equivalents of what you are used to.  Some medications work out to be somewhat costly (but I am looking from the UK perspective, where a set fee applies).

There is a large problem with fake medication in Kenya, particularly of big brands so make sure that you are aware of this and check packaging.

Stick to the pharmacist outlets in better areas/shopping malls.  I cant recommend a specific one, as we haven't lived in Nairobi for some years.