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I. Sulfasalazine

Mainly used for inflammatory bowel disease, rheumatoid polyarthritis, hemorrhagic proctitis.

1. Usage and dosage

The initial dose is 1~2g per day, divided into 3~4 times orally; in the first few weeks, gradually increase the dose to 3~4g a day, orally 3~4 times; after the symptoms improve, it can be gradually reduced to the maintenance amount. 1.5g a day, 3 times, until the symptoms disappear completely.

2. The main reason

Gastrointestinal reaction: sulfasalazine, which is broken down by bacteria into sulfapyridine and 5-aminosalicylic acid in the intestine. The main active ingredient is 5-aminosalicylic acid, which can stimulate the gastrointestinal tract, cause stomach pain and abdominal pain, and patients are poorly tolerated.

In the case of gastrointestinal irritation, in addition to medication after meals, it can also be divided into small doses, or even once an hour, to reduce symptoms.

 

II. Carbamazepine

Mainly used for epilepsy, trigeminal neuralgia and glossopharyngeal neuralgia, psychosis, restless legs syndrome, lateral hemiplegia and so on.

1. Usage and dosage

The initial dose, 100 ~ 200mg each time, 1 or 2 times a day; the next day after the increase of 100mg, until the efficacy, the maximum amount does not exceed 1.2g per day; maintenance should be adjusted according to the situation and blood drug concentration monitoring results To the lowest effective amount.

2. The main reason

Individual differences: oral absorption is slow, and varies from person to person; different patients take the same dose (400mg), blood concentration can vary between 0.5-25μg / mL (effective concentration range: 4 ~ 12ug / mL).

Induction of self metabolism: carbamazepine is metabolized by the liver and can induce its own metabolism; after 4 weeks of treatment, it may be necessary to increase the dose to avoid the decrease of blood concentration caused by self-induced.

Serious adverse reactions: central nervous system toxicity is the most common, manifested as blurred vision, diplopia, nystagmus, etc.; can cause arrhythmia, atrioventricular block, bradycardia, etc.; can cause toxic epidermal necrolysis.

 

III. Atorvastatin

Mainly used for hypercholesterolemia.

1. Usage and dosage

The initial dose is 10 mg/day per day; the dose can be adjusted stepwise to 40 mg/day every 4 weeks; the maximum dose is 80 mg once daily. It can be taken at any time of the day and is not affected by meals.

2. The main reason

Dose-effect relationship: doubling the dose of statin administered can only reduce LDL-C by about 6%. For example, atorvastatin, 10mg daily, can reduce LDL-C 31~35%, 20mg per day, can only reduce LDL-C 36~40%.

Dose-muscle toxicity relationship: Muscle toxicity includes three major manifestations of myalgia, myopathy, and rhabdomyolysis, all in a dose-dependent manner, independent of the cholesterol-lowering effect of the drug. The study found that 80 mg / day of atorvastatin is 5 times more likely to induce symptoms of muscle toxicity than 10 mg / day.

 

IV. Levothyroxine

It is mainly used for alternative treatment of hypothyroidism for various reasons.

1. Usage and dosage

The initial dose, 25~50ug daily, is fasted in the morning; after the initial dose, increase 25~50ug every 2~4 weeks until the maintenance dose: 100~200ug daily.

2. The main reason

The therapeutic index is narrow: in addition to symptomatic treatment, the dose must be titrated carefully. Excessive medication will not only produce the same symptoms and signs as hyperthyroidism, but also events such as confusion, disorientation, cerebral embolism, shock, coma and death.

Symptoms caused by excessive doses are not necessarily obvious, and symptoms may occur after a few days of levothyroxine sodium intake.

 

V. Nifedipine

Mainly used for angina and high blood pressure.

1. Usage and dosage

Nifedipine tablets: the general starting dose of 10mg / time, 3 times a day orally; the usual maintenance dose is oral 10 ~ 20mg / time, 3 times a day.

Nifedipine controlled release tablets: usually the initial dose of treatment is 30mg daily, once a day; the maximum dose, 60mg daily, once a day.

Dose adjustment: Usually it takes 7 to 14 days to adjust the dose. If the patient’s symptoms are obvious and the condition is urgent, the dose adjustment period can be shortened appropriately.

2. The main reason

The phenomenon of stealing blood: nifedipine is a rapid-acting antihypertensive drug, blood pressure drops too fast or too large, can cause coronary artery stealing, leading to myocardial ischemia or myocardial infarction.

Large individual differences: The plasma concentration of nifedipine is closely related to clinical efficacy, and there are obvious individual differences. The plasma concentration of nifedipine is affected by many factors, including formulation factors, ethnic factors, genetic polymorphisms of drug-metabolizing enzymes, dietary factors, and combined drugs.

 

VI. Angiotensin converting enzyme inhibitor

Mainly used for hypertension, chronic heart failure and treatment after acute myocardial infarction. Take enalapril as an example.

1. Usage and dosage

Hypertension: The initial dose is 10-20 mg once daily; the usual maintenance dose is 20 mg/day, which can be adjusted to a maximum dose of 40 mg per day according to the patient’s needs.

In combination with diuretics for the treatment of hypertension: because these patients may have insufficient blood volume or loss of salt, symptomatic hypotension may occur after starting enalapril, starting from 5 mg / day or less.

Symptomatic heart failure or asymptomatic left ventricular dysfunction: starting dose of 2.5 mg, and should be taken under close medical supervision; within 2 to 4 weeks, according to the patient’s tolerance, the dose is gradually increased to The usual maintenance dose is 20 mg / day.

2. The main reason

The first dose of hypotension: mainly related to cerebral blood flow insufficiency, while blood pressure is reduced, mild loss of control, dizziness, headache, general malaise, visual impairment, etc., can cause falls in the elderly, and can cause temporary Loss of sexual perception, bradycardia.

Captopril’s first hypotensive occurs rapidly but with short duration; the first dose of enalapril and quinapril is slower but lasts longer; the first dose of perindopril and fosinopril is low The blood pressure is very slight.

 

VII. Beta-blockers

Mainly used for angina pectoris, acute myocardial infarction, heart failure, high blood pressure and so on. Take Metoprolol as an example.

1. Usage and dosage

Angina pectoris: start 25-50mg once a day, 2-4 times a day; gradually increase the dose by one week until the target dose is reached; the maximum daily dose is 400mg, divided into 3 times. Ordinary tablets are greatly affected by food and should be taken on an empty stomach.

Target dose: resting heart rate dropped to 55-60 beats / min.

2. The main reason

Individual differences: Metoprolol is mainly metabolized by the CYP2D6 in the liver. Affected by genetic factors and other factors, metoprolol’s internal processes vary widely, and doses must be individualized to avoid bradycardia.

Metoprolol tartrate should be gradually reduced in about 2 weeks to avoid serious cardiovascular problems (such as myocardial infarction, arrhythmia, sudden death, etc.).

 

VIII. α-blockers

Mainly used to treat benign prostatic hyperplasia and hypertension. Take terazosin as an example.

1. Usage and dosage

Benign prostatic hyperplasia: The initial dose is 1 mg before bedtime and should not be exceeded; the daily dose may be doubled after one or two weeks to achieve the desired effect. The usual maintenance dose is 5-10 mg once a day.

If you discontinue the use of terazosin for a period of time, you should still take it from a small dose of the first dose.

2. The main reason

The first dose of hypotension: terazosin inhibits the adrenergic alpha 1 receptor, causing a drop in blood pressure, especially a significant decrease in diastolic blood pressure. Significant hypotension may occur after the first dose, and even cause syncope.

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