Combativeness is rooted in a person's failed attempts to actually communicate something to you.
Perhaps first look at what is driving this combativeness or fear. What is the source of the apprehension behind taking his or her meds? Could it be trouble swallowing? Does the pill have an unpleasant after taste? Is it the time of day when medications are taken? Has something, perhaps when younger, made them nervous about taking pills?
To ease the process, first prepare the environment. The setting should be calm and free of disruptions. Play soft music. Walk through the steps of what you are going to do: "It's time to take your medicine that the doctor wants you to take. (pause) Drink some water first. (pause) Here's your first pill. (pause) Make sure to swallow." Use short, simple instructions, don't rush and allow them, as much as possible, to take medications on their own terms. You could even offer a favorite treat, like a piece of chocolate, for after taking the pills.
The resistance to taking medications may be due to some medical issues, such as a urinary tract infection, cold or flu or a sore throat. Or it could be dental issues, such as sore gums or poorly fitting dentures.
Sometimes, just the sight of pill bottles can cause anxiety, so consider keeping bottles out of sight while giving medications. Try putting the pills in a solid-colored bowl and giving them one at a time.
If you are a regular caregiver, it might be that the person is taking their aggression out on you alone. Try giving the responsibility to another close relative.
Before giving any medications, try redirecting the person by engaging in an activity he or she enjoys or offering compliments to ease the anxiety about taking pills. Additionally, if you take medications, try alternating with them — you swallow a pill then they swallow one. This visual example might help them understand more about the process.
If the pills are large or difficult to swallow, ask the physician or pharmacist about crushing them and mixing with applesauce or yogurt.
If the person's combativeness escalates, set everything aside for a few minutes and try again. Behaviors change over time, so you may need to constantly modify your procedures.
As always, consult your physician or pharmacist with issues out of the ordinary in giving medications. It might be that the medications could be adjusted to be taken at a time of day better for the person.