Memorizing Pharmacology Video 7 of 7
Welcome to the final chapter article of Memorizing Pharmacology. Here we discuss endocrine medications and some related renal and reproductive disorders. By having completed this review hopefully it will make it much easier for you to succeed in pharmacology and maybe even enjoy its usefulness.
OTC insulin and emergency contraception.
We’ll start with our available OTC medications. Two insulins come without a prescription: regular insulin and NPH insulin. Why don’t many people get insulin without a prescription? Insulin is expensive as are the supplies like needles, blood glucose monitor, test strips, and lancets. It’s less expensive to get a prescription so prescription insurance might cover part of the cost. We’ll continue with insulin in a second, but one other OTC item includes Plan-B One Step, a single pill containing a high dose of a levonorgestrel, a progestin.
Diabetes and insulin.
We make insulin with our pancreatic beta cells, but people with diabetes either don’t make enough insulin (Type I diabetes) or are resistant to insulin (Type II diabetes), or both (late-stage Type II diabetes). For Type I patients, insulin is a must; type I patients were born with dysfunctional beta cells and will need life-long exogenous insulin. For type II patients, insulin is held until a patient is on other anti-diabetic medications first. This is for many reasons: insulin is expensive even after insurance, many patients don’t like injections, and insulin predisposes people to weight gain and possible hypoglycemia. Now let’s look at some different types of insulin.
Insulin lispro is a rapid-acting insulin. It starts working in 15 minutes and lasts about 4 hours.
Regular insulin is a short-acting insulin. It starts working in 30 minutes and lasts about 8 hours.
NPH insulin is an intermediate-acting insulin. It starts working in 1-2 hours and lasts about 12 hours.
Insulin glargine is a long-acting insulin. It starts working in an hour and lasts about 24 hours.
Typically, shorter acting insulin is for mealtime, while longer acting insulin is for daytime glucose control. Patients often use short and long acting insulin, which may mean many shots daily.
Metformin is a biguanide oral medication and a foundational part of Type II control. Almost all Type II diabetics are started on metformin because research shows this drug reduces mortality in diabetics. It has little risk of hypoglycemia.
The DPP-4 inhibitors, or gliptins, prevent the break down of other hormones that increase insulin secretion, promote insulin sensitivity and a full feeling. If we inhibit DPP-4, we have more GLP-1 and incretin available.
We also have an anti-diabetic class called the 2nd generation sulfonylureas. The 1st generation of these drug caused too many side effects, so they were discontinued. Medications in this class have the stem gly- or gli-. Sulfonylureas increase insulin secretion. This mechanism works for patients that still have functional beta cells, but patients with Type I or late stage type II, these medications won’t provide much benefit.
Sometimes patients have episodes of too little blood glucose, or hypoglycemia. Hypoglycemia leads to coma and death. Glucagon can be used in these cases. It must be injected, so this medication is reserved when a patient’s blood sugars are so low, they pass out. If a patient’s blood sugars are low but they are conscious, it’s best to give them something to eat or drink that will quickly increase their blood sugar level with orange juice, fruit snacks, or glucose tablets.
Thyroid hormone stimulates metabolism, the heart, and cell growth. Patients can have too much thyroid hormone (hyperthyroidism) or not enough (hypothyroidism). Of the two, hypothyroidism is more common and easier to treat.
In hypothyroidism, you see slow heart rate, fatigue, constipation, and weight gain. Much like exogenous insulin treats diabetes, exogenous thyroid hormone treats hypothyroidism. Levothyroxine is exogenous thyroid hormone to help increase levels. Like insulin, patients can be on levothyroxine for life.
Patients with hyperthyroidism, will have opposite symptoms like fast heart rate, energy, diarrhea, and weight loss. This may require surgery to remove part or all of the thyroid gland. Nevertheless, patients usually start propylthiouracil, or PTU for short.
Hormones and contraception.
Men with low testosterone can be prescribed exogenous testosterone to bring levels back up. The stem for steroids is –ster- and testosterone is a steroid that comes as an injection, gel, or patch.
Many contraceptive combinations include ethinyl estradiol. Progestins differ a bit – some have different side effect profiles – many have the stem –gest-. Contraceptive combinations can come as daily oral pills, a patch, or a vaginal ring. Some packs will include a week’s worth of iron pills or sugar pills to help keep the habit of a daily pill with or without an estrogen or progestin ingredient. This triple combination with iron combination is normally reserved for anemic patients.
Overactive bladder, urinary retention, erectile dysfunction, benign prostatic hyperplasia.
The last section includes a mixture of common genitourinary conditions. The primary symptom of OAB is the frequent feeling of urination, even when the bladder is not full. We use anticholinergics like oxybutynin, solifenacin, and tolterodine. Recall anticholinergics tend to be drying, so side effects will include dry mouth, constipation, and dry eyes.
Urinary retention is the opposite problem of OAB. So instead of using anticholinergics, we use cholinergics. The one medication you should learn for urinary retention is bethanechol. The –chol suffix is not a stem, but it helps you remember that bethanechol is a cholinergic drug. Side effects will be the opposite of the anticholinergics, including possible diarrhea and excessive tear production.
Erectile dysfunction (ED) describes the inability for men to achieve or maintain an erection. The PDE-5 inhibitors with the stem –afil help. They are absolutely contraindicated in patients taking nitrates, including nitroglycerin. This combination can cause a potentially fatal drop in blood pressure.
BPH describes a non-cancerous growth of the prostate. Alpha-blockers that include tamsulosin and alfuzosin don’t change the prostate size; rather, relax the smooth muscle within the prostate providing less urine flow resistance. 5-alpha reductase inhibitors reduce the prostate size by inhibiting the last enzyme needed to synthesize the hormone helping the prostate to shrink.
That concludes the chapter articles on Memorizing Pharmacology. I hope you enjoyed reading the articles as much as I enjoyed writing them.
OTC insulin and emergency contraceptionOTC insulinRegular insulin
NPH insulinOTC emergency contraceptionLevonorgestrelDiabetes and insulin
Rapid actingInsulin lisproShort actingRegular insulinIntermediate actingNPH insulinLong durationInsulin glargineBiguanidesMetforminDPP-4 inhibitorsSitagliptinSulfonylureas 2nd generationGlipizide
HypothyroidismLevothyroxineHyperthyroidismPropylthiouracil (PTU)Hormones and contraception
TestosteroneTestosteroneContraception – combined oral contraceptives (COCs)Norethindrone / ethinyl estradiol / ferrous fumarateNorgestimate / ethinyl estradiolContraception – patchNorelgestromin / ethinyl estradiolContraception – ringEtonogestrel / ethinyl estradiolOveractive bladder, urinary retention, erectile dysfunction, benign prostatic hyperplasia
TadalafilBPH – alpha blockersTamsulosin
AlfuzosinBPH – 5-alpha reductase inhibitorsDutasteride
About TonyPharmD Pro
Tony is a pharmacist and pharmacology professor with triplet daughters teaching pharmacology for almost a decade.
Joined Jan '17; Posts: 15; Likes: 71.