For example I take three different types of medication for migraines. One is a monthly injection, one is a dissolvable pill and another is just a regular pill I take. How do the researchers decide the best way for patients to take the pills?
Also I am terrible at chemistry so if anyone’s explanation includes that, please dumb it down as best as you can.
In: 2
Drugs go through first pass metabolism which means the that certain drugs can be inactivated if you take orally. Other drugs (IV formulations, sublingual and buccal routes) are administered to avoid becoming non-functional or having their ability to treat diminished by being given via an alternate route.
In general, injections are better in that more of the drug actually gets to what it is supposed to do. A large portion of the drug you take orally as a pill gets discharged of by the liver right after being digested. So pills put more strain on your liver for the set amount of effect. On the other hand, all injections run a small risk a trauma or infection, so they have their downsides too. This balance of upsides and downsides is what matters when choosing the form of medicine to use.
In very simple terms, some drugs won’t survive the passage through the stomach without losing effectiveness (administered by injection etc), others are fine and get absorbed (pill).
Generally taking medication by mouth is safest so that’s used unless it won’t work for some reason, most commonly because the stomach will destroy some drugs. Injections bypass the stomach but piercing the skin causes a danger of infection and sharp needles are dangerous in other ways, not to mention being more painful.
My migraine neurologist only gives me injection and dissolvable meds because my stomach is so sensitive I always end up vomiting regular pills up. So how the patient tolerates the meds is a factor.
I’ll answer your second question first: pharmaceutical companies do a lot of research first to determine how a drug will be available. We’ve been doing this type of research for hundreds of years, and through trial and error, we know some things work better orally, some don’t…..long answer involves pharmacodynamics and pharmacokinetics.
Mostly scientists know how the drug “should” work, then they do animal trials and see if that works. If it does they move to human trials.
Generally speaking the “best” way/ most efficient way to give a medication is intravenous, or IV. You can give far less for the same effect in a quicker time frame. But there are drawbacks: 1) your average patient isn’t going to be able to shoot themselves up at home and 2) your veins get irritated very quickly by foreign substances. This is why IV drug users have track marks and have to rotate sites so frequently.
Next “best” is through a mucus membrane, so intranasally (IN), rectally (PR) or sublingually (SL or ODT). You have pretty rapid absorption through your mucus membranes (“butt chugging” anyone?) Which is why people snort drugs. But once again, this is delicate tissue, so it can get damaged easily and again, patient compliance can be an issue.
So orally is the best if you have a patient self administering….but sometimes the drug can safely pass through the acid in the stomach, or you need an even slower distribution, so you get injectables that are intramuscular (IM) or subcutaneous (SQ). Injectables work faster generally (15-20 min vs 30-45 generally), but there’s not a huge difference. So it once again comes down to what’s easiest for a patient to administer in their own. Generally people prefer to avoid needles, so orally it is.
Some drugs are better given in pills because they degrade in your stomach slower than if you were to inject the same amount of the drug into a vein. Think of drugs that need to have a long acting effect: you want a little bit of the drug in your body at all times, so a slow release from your stomach is better. Oral contraception for example is built to have as constant a level of hormones as possible.
Other drugs are best given in a vein because that brings them to the place you need them super fast. Like doctors giving people adrenaline shots on tv shows when people are “crashing”. Those drugs usually have a short but fast effect.
And then some drugs need to be given a certain way because the molecule can be harmful if given the wrong way, or just be very painful during the injection. Or they could just be deactivated by the stomach acid so they need to be given with an injection.
As for how researchers determine what’s best, it’s a whole process of experimenting and monitoring drugs levels in the patient and their effects over time. The first thing they check is that the drug isn’t harmful if given a certain way. Then they check that it triggers the appropriate response for the appropriate amount of time.
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