When taking medicine orally in tablet or capsule form, unless instructed otherwise you should always wash down the medicine with plenty of water! Also, last thing at night may often be not the best time to take pills -- especially not while lying down.
A recently-published case study reports the case of a teenage girl who was taking the antibiotic doxycycline in capsule form as treatment for the common skin-problem, acne. After 3 months, she developed symptoms of indigestion (heartburn), chest pain, and difficulty of swallowing; these persisted for several weeks.
Endoscope examination of her throat showed severe internal ulceration at the middle and lower sections. This was similar to what is seen in cases of throat cancer, so tissue samples were removed and tested; however, no cancer was found.
Treatment consisted of stopping the doxycycline, and giving two drugs (sucralfate and omeprazole) commonly prescribed for treatment of gastric ulcer symptoms. All her symptoms disappeared on the third day of the treatment, but it was continued for 4 weeks. After this time, a second endoscope examination showed that the ulceration had healed.
Questioning revealed that the patient had habitually swallowed the doxycycline capsule without any liquid, and furthermore had taken it while lying down in bed, just before going to sleep at night. Particularly since body-metabolism slows down during sleep, this meant that her throat tissues were regularly exposed to the drug in very concentrated form.
To prevent irritation of the aesophagus and stomach, it is advised that pills should be taken with a full glass of water; and patients should be in an upright position during administration, and for at least 30 minutes afterwards. This is especially important for drugs taken in capsule form, since these are more liable than tablets to stick to the inside of the throat.